OSSL-GUIDE-MIGRATION(7SSL) OpenSSL OSSL-GUIDE-MIGRATION(7SSL)
NAME
ossl-guide-migration, migration_guide - OpenSSL Guide: Migrating from
older OpenSSL versions
SYNOPSIS
See the individual manual pages for details.
DESCRIPTION
This guide details the changes required to migrate to new versions of
OpenSSL. Currently this covers OpenSSL 3.0 & 3.1. For earlier versions
refer to <https://github.com/openssl/openssl/blob/master/CHANGES.md>.
For an overview of some of the key concepts introduced in OpenSSL 3.0
see crypto(7).
OPENSSL 3.1
Main Changes from OpenSSL 3.0
The FIPS provider in OpenSSL 3.1 includes some non-FIPS validated
algorithms, consequently the property query "fips=yes" is mandatory for
applications that want to operate in a FIPS approved manner. The
algorithms are:
Triple DES ECB
Triple DES CBC
EdDSA
There are no other changes requiring additional migration measures since
OpenSSL 3.0.
OPENSSL 3.0
Main Changes from OpenSSL 1.1.1
Major Release
OpenSSL 3.0 is a major release and consequently any application that
currently uses an older version of OpenSSL will at the very least need
to be recompiled in order to work with the new version. It is the
intention that the large majority of applications will work unchanged
with OpenSSL 3.0 if those applications previously worked with OpenSSL
1.1.1. However this is not guaranteed and some changes may be required
in some cases. Changes may also be required if applications need to take
advantage of some of the new features available in OpenSSL 3.0 such as
the availability of the FIPS module.
License Change
In previous versions, OpenSSL was licensed under the dual OpenSSL and
SSLeay licenses <https://www.openssl.org/source/license-openssl-
ssleay.txt> (both licenses apply). From OpenSSL 3.0 this is replaced by
the Apache License v2 <https://www.openssl.org/source/apache-
license-2.0.txt>.
Providers and FIPS support
One of the key changes from OpenSSL 1.1.1 is the introduction of the
Provider concept. Providers collect together and make available
algorithm implementations. With OpenSSL 3.0 it is possible to specify,
either programmatically or via a config file, which providers you want
to use for any given application. OpenSSL 3.0 comes with 5 different
providers as standard. Over time third parties may distribute additional
providers that can be plugged into OpenSSL. All algorithm
implementations available via providers are accessed through the "high
level" APIs (for example those functions prefixed with "EVP"). They
cannot be accessed using the "Low Level APIs".
One of the standard providers available is the FIPS provider. This makes
available FIPS validated cryptographic algorithms. The FIPS provider is
disabled by default and needs to be enabled explicitly at configuration
time using the "enable-fips" option. If it is enabled, the FIPS provider
gets built and installed in addition to the other standard providers. No
separate installation procedure is necessary. There is however a
dedicated "install_fips" make target, which serves the special purpose
of installing only the FIPS provider into an existing OpenSSL
installation.
Not all algorithms may be available for the application at a particular
moment. If the application code uses any digest or cipher algorithm via
the EVP interface, the application should verify the result of the
EVP_EncryptInit(3), EVP_EncryptInit_ex(3), and EVP_DigestInit(3)
functions. In case when the requested algorithm is not available, these
functions will fail.
See also "Legacy Algorithms" for information on the legacy provider.
See also "Completing the installation of the FIPS Module" and "Using the
FIPS Module in applications".
Low Level APIs
OpenSSL has historically provided two sets of APIs for invoking
cryptographic algorithms: the "high level" APIs (such as the "EVP" APIs)
and the "low level" APIs. The high level APIs are typically designed to
work across all algorithm types. The "low level" APIs are targeted at a
specific algorithm implementation. For example, the EVP APIs provide
the functions EVP_EncryptInit_ex(3), EVP_EncryptUpdate(3) and
EVP_EncryptFinal(3) to perform symmetric encryption. Those functions can
be used with the algorithms AES, CHACHA, 3DES etc. On the other hand,
to do AES encryption using the low level APIs you would have to call AES
specific functions such as AES_set_encrypt_key(3), AES_encrypt(3), and
so on. The functions for 3DES are different. Use of the low level APIs
has been informally discouraged by the OpenSSL development team for a
long time. However in OpenSSL 3.0 this is made more formal. All such low
level APIs have been deprecated. You may still use them in your
applications, but you may start to see deprecation warnings during
compilation (dependent on compiler support for this). Deprecated APIs
may be removed from future versions of OpenSSL so you are strongly
encouraged to update your code to use the high level APIs instead.
This is described in more detail in "Deprecation of Low Level Functions"
Legacy Algorithms
Some cryptographic algorithms such as MD2 and DES that were available
via the EVP APIs are now considered legacy and their use is strongly
discouraged. These legacy EVP algorithms are still available in OpenSSL
3.0 but not by default. If you want to use them then you must load the
legacy provider. This can be as simple as a config file change, or can
be done programmatically. See OSSL_PROVIDER-legacy(7) for a complete
list of algorithms. Applications using the EVP APIs to access these
algorithms should instead use more modern algorithms. If that is not
possible then these applications should ensure that the legacy provider
has been loaded. This can be achieved either programmatically or via
configuration. See crypto(7) man page for more information about
providers.
Engines and "METHOD" APIs
The refactoring to support Providers conflicts internally with the APIs
used to support engines, including the ENGINE API and any function that
creates or modifies custom "METHODS" (for example EVP_MD_meth_new(3),
EVP_CIPHER_meth_new(3), EVP_PKEY_meth_new(3), RSA_meth_new(3),
EC_KEY_METHOD_new(3), etc.). These functions are being deprecated in
OpenSSL 3.0, and users of these APIs should know that their use can
likely bypass provider selection and configuration, with unintended
consequences. This is particularly relevant for applications written to
use the OpenSSL 3.0 FIPS module, as detailed below. Authors and
maintainers of external engines are strongly encouraged to refactor
their code transforming engines into providers using the new Provider
API and avoiding deprecated methods.
Support of legacy engines
If openssl is not built without engine support or deprecated API
support, engines will still work. However, their applicability will be
limited.
New algorithms provided via engines will still work.
Engine-backed keys can be loaded via custom OSSL_STORE implementation.
In this case the EVP_PKEY objects created via ENGINE_load_private_key(3)
will be considered legacy and will continue to work.
To ensure the future compatibility, the engines should be turned to
providers. To prefer the provider-based hardware offload, you can
specify the default properties to prefer your provider.
Setting engine-based or application-based default low-level crypto
method such as RSA_METHOD or EC_KEY_METHOD is still possible and keys
inside the default provider will use the engine-based implementation for
the crypto operations. However EVP_PKEYs created by decoding by using
OSSL_DECODER, PEM_ or d2i_ APIs will be provider-based. To create a
fully legacy EVP_PKEYs EVP_PKEY_set1_RSA(3), EVP_PKEY_set1_EC_KEY(3) or
similar functions must be used.
Versioning Scheme
The OpenSSL versioning scheme has changed with the OpenSSL 3.0 release.
The new versioning scheme has this format:
MAJOR.MINOR.PATCH
For OpenSSL 1.1.1 and below, different patch levels were indicated by a
letter at the end of the release version number. This will no longer be
used and instead the patch level is indicated by the final number in the
version. A change in the second (MINOR) number indicates that new
features may have been added. OpenSSL versions with the same major
number are API and ABI compatible. If the major number changes then API
and ABI compatibility is not guaranteed.
For more information, see OpenSSL_version(3).
Other major new features
Certificate Management Protocol (CMP, RFC 4210)
This also covers CRMF (RFC 4211) and HTTP transfer (RFC 6712) See
openssl-cmp(1) and OSSL_CMP_exec_certreq(3) as starting points.
HTTP(S) client
A proper HTTP(S) client that supports GET and POST, redirection, plain
and ASN.1-encoded contents, proxies, and timeouts.
Key Derivation Function API (EVP_KDF)
This simplifies the process of adding new KDF and PRF implementations.
Previously KDF algorithms had been shoe-horned into using the EVP_PKEY
object which was not a logical mapping. Existing applications that use
KDF algorithms using EVP_PKEY (scrypt, TLS1 PRF and HKDF) may be slower
as they use an EVP_KDF bridge internally. All new applications should
use the new EVP_KDF(3) interface. See also "Key Derivation Function
(KDF)" in OSSL_PROVIDER-default(7) and "Key Derivation Function (KDF)"
in OSSL_PROVIDER-FIPS(7).
Message Authentication Code API (EVP_MAC)
This simplifies the process of adding MAC implementations.
This includes a generic EVP_PKEY to EVP_MAC bridge, to facilitate the
continued use of MACs through raw private keys in functionality such as
EVP_DigestSign(3) and EVP_DigestVerify(3).
All new applications should use the new EVP_MAC(3) interface. See also
"Message Authentication Code (MAC)" in OSSL_PROVIDER-default(7) and
"Message Authentication Code (MAC)" in OSSL_PROVIDER-FIPS(7).
Algorithm Fetching
Using calls to convenience functions such as EVP_sha256() and
EVP_aes_256_gcm() may incur a performance penalty when using providers.
Retrieving algorithms from providers involves searching for an algorithm
by name. This is much slower than directly accessing a method table.
It is recommended to prefetch algorithms if an algorithm is used many
times. See "Performance" in crypto(7), "Explicit fetching" in crypto(7)
and "Implicit fetching" in crypto(7).
Support for Linux Kernel TLS
In order to use KTLS, support for it must be compiled in using the
"enable-ktls" configuration option. It must also be enabled at run time
using the SSL_OP_ENABLE_KTLS option.
New Algorithms
• KDF algorithms "SINGLE STEP" and "SSH"
See EVP_KDF-SS(7) and EVP_KDF-SSHKDF(7)
• MAC Algorithms "GMAC" and "KMAC"
See EVP_MAC-GMAC(7) and EVP_MAC-KMAC(7).
• KEM Algorithm "RSASVE"
See EVP_KEM-RSA(7).
• Cipher Algorithm "AES-SIV"
See "SIV Mode" in EVP_EncryptInit(3).
• AES Key Wrap inverse ciphers supported by EVP layer.
The inverse ciphers use AES decryption for wrapping, and AES
encryption for unwrapping. The algorithms are: "AES-128-WRAP-INV",
"AES-192-WRAP-INV", "AES-256-WRAP-INV", "AES-128-WRAP-PAD-INV",
"AES-192-WRAP-PAD-INV" and "AES-256-WRAP-PAD-INV".
• CTS ciphers added to EVP layer.
The algorithms are "AES-128-CBC-CTS", "AES-192-CBC-CTS",
"AES-256-CBC-CTS", "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS"
and "CAMELLIA-256-CBC-CTS". CS1, CS2 and CS3 variants are
supported.
CMS and PKCS#7 updates
• Added CAdES-BES signature verification support.
• Added CAdES-BES signature scheme and attributes support (RFC 5126)
to CMS API.
• Added AuthEnvelopedData content type structure (RFC 5083) using
AES_GCM
This uses the AES-GCM parameter (RFC 5084) for the Cryptographic
Message Syntax. Its purpose is to support encryption and decryption
of a digital envelope that is both authenticated and encrypted using
AES GCM mode.
• PKCS7_get_octet_string(3) and PKCS7_type_is_other(3) were made
public.
PKCS#12 API updates
The default algorithms for pkcs12 creation with the PKCS12_create()
function were changed to more modern PBKDF2 and AES based algorithms.
The default MAC iteration count was changed to PKCS12_DEFAULT_ITER to
make it equal with the password-based encryption iteration count. The
default digest algorithm for the MAC computation was changed to SHA-256.
The pkcs12 application now supports -legacy option that restores the
previous default algorithms to support interoperability with legacy
systems.
Added enhanced PKCS#12 APIs which accept a library context OSSL_LIB_CTX
and (where relevant) a property query. Other APIs which handle PKCS#7
and PKCS#8 objects have also been enhanced where required. This
includes:
PKCS12_add_key_ex(3), PKCS12_add_safe_ex(3), PKCS12_add_safes_ex(3),
PKCS12_create_ex(3), PKCS12_decrypt_skey_ex(3), PKCS12_init_ex(3),
PKCS12_item_decrypt_d2i_ex(3), PKCS12_item_i2d_encrypt_ex(3),
PKCS12_key_gen_asc_ex(3), PKCS12_key_gen_uni_ex(3),
PKCS12_key_gen_utf8_ex(3), PKCS12_pack_p7encdata_ex(3),
PKCS12_pbe_crypt_ex(3), PKCS12_PBE_keyivgen_ex(3),
PKCS12_SAFEBAG_create_pkcs8_encrypt_ex(3), PKCS5_pbe2_set_iv_ex(3),
PKCS5_pbe_set0_algor_ex(3), PKCS5_pbe_set_ex(3), PKCS5_pbkdf2_set_ex(3),
PKCS5_v2_PBE_keyivgen_ex(3), PKCS5_v2_scrypt_keyivgen_ex(3),
PKCS8_decrypt_ex(3), PKCS8_encrypt_ex(3), PKCS8_set0_pbe_ex(3).
As part of this change the EVP_PBE_xxx APIs can also accept a library
context and property query and will call an extended version of the
key/IV derivation function which supports these parameters. This
includes EVP_PBE_CipherInit_ex(3), EVP_PBE_find_ex(3) and
EVP_PBE_scrypt_ex(3).
PKCS#12 KDF versus FIPS
Unlike in 1.x.y, the PKCS12KDF algorithm used when a PKCS#12 structure
is created with a MAC that does not work with the FIPS provider as the
PKCS12KDF is not a FIPS approvable mechanism.
See EVP_KDF-PKCS12KDF(7), PKCS12_create(3), openssl-pkcs12(1),
OSSL_PROVIDER-FIPS(7).
Windows thread synchronization changes
Windows thread synchronization uses read/write primitives (SRWLock) when
supported by the OS, otherwise CriticalSection continues to be used.
Trace API
A new generic trace API has been added which provides support for
enabling instrumentation through trace output. This feature is mainly
intended as an aid for developers and is disabled by default. To utilize
it, OpenSSL needs to be configured with the "enable-trace" option.
If the tracing API is enabled, the application can activate trace output
by registering BIOs as trace channels for a number of tracing and
debugging categories. See OSSL_trace_enabled(3).
Key validation updates
EVP_PKEY_public_check(3) and EVP_PKEY_param_check(3) now work for more
key types. This includes RSA, DSA, ED25519, X25519, ED448 and X448.
Previously (in 1.1.1) they would return -2. For key types that do not
have parameters EVP_PKEY_param_check(3) will always return 1.
Other notable deprecations and changes
The function code part of an OpenSSL error code is no longer relevant
This code is now always set to zero. Related functions are deprecated.
STACK and HASH macros have been cleaned up
The type-safe wrappers are declared everywhere and implemented once.
See DEFINE_STACK_OF(3) and DEFINE_LHASH_OF_EX(3).
The RAND_DRBG subsystem has been removed
The new EVP_RAND(3) is a partial replacement: the DRBG callback
framework is absent. The RAND_DRBG API did not fit well into the new
provider concept as implemented by EVP_RAND and EVP_RAND_CTX.
Removed FIPS_mode() and FIPS_mode_set()
These functions are legacy APIs that are not applicable to the new
provider model. Applications should instead use
EVP_default_properties_is_fips_enabled(3) and
EVP_default_properties_enable_fips(3).
Key generation is slower
The Miller-Rabin test now uses 64 rounds, which is used for all prime
generation, including RSA key generation. This affects the time for
larger keys sizes.
The default key generation method for the regular 2-prime RSA keys was
changed to the FIPS186-4 B.3.6 method (Generation of Probable Primes
with Conditions Based on Auxiliary Probable Primes). This method is
slower than the original method.
Change PBKDF2 to conform to SP800-132 instead of the older PKCS5 RFC2898
This checks that the salt length is at least 128 bits, the derived key
length is at least 112 bits, and that the iteration count is at least
1000. For backwards compatibility these checks are disabled by default
in the default provider, but are enabled by default in the FIPS
provider.
To enable or disable the checks see OSSL_KDF_PARAM_PKCS5 in
EVP_KDF-PBKDF2(7). The parameter can be set using EVP_KDF_derive(3).
Enforce a minimum DH modulus size of 512 bits
Smaller sizes now result in an error.
SM2 key changes
EC EVP_PKEYs with the SM2 curve have been reworked to automatically
become EVP_PKEY_SM2 rather than EVP_PKEY_EC.
Unlike in previous OpenSSL versions, this means that applications cannot
call EVP_PKEY_set_alias_type(pkey, EVP_PKEY_SM2) to get SM2
computations.
Parameter and key generation is also reworked to make it possible to
generate EVP_PKEY_SM2 parameters and keys. Applications must now
generate SM2 keys directly and must not create an EVP_PKEY_EC key first.
It is no longer possible to import an SM2 key with domain parameters
other than the SM2 elliptic curve ones.
Validation of SM2 keys has been separated from the validation of regular
EC keys, allowing to improve the SM2 validation process to reject loaded
private keys that are not conforming to the SM2 ISO standard. In
particular, a private scalar k outside the range 1 <= k < n-1 is now
correctly rejected.
EVP_PKEY_set_alias_type() method has been removed
This function made a EVP_PKEY object mutable after it had been set up.
In OpenSSL 3.0 it was decided that a provided key should not be able to
change its type, so this function has been removed.
Functions that return an internal key should be treated as read only
Functions such as EVP_PKEY_get0_RSA(3) behave slightly differently in
OpenSSL 3.0. Previously they returned a pointer to the low-level key
used internally by libcrypto. From OpenSSL 3.0 this key may now be held
in a provider. Calling these functions will only return a handle on the
internal key where the EVP_PKEY was constructed using this key in the
first place, for example using a function or macro such as
EVP_PKEY_assign_RSA(3), EVP_PKEY_set1_RSA(3), etc. Where the EVP_PKEY
holds a provider managed key, then these functions now return a cached
copy of the key. Changes to the internal provider key that take place
after the first time the cached key is accessed will not be reflected
back in the cached copy. Similarly any changes made to the cached copy
by application code will not be reflected back in the internal provider
key.
For the above reasons the keys returned from these functions should
typically be treated as read-only. To emphasise this the value returned
from EVP_PKEY_get0_RSA(3), EVP_PKEY_get0_DSA(3), EVP_PKEY_get0_EC_KEY(3)
and EVP_PKEY_get0_DH(3) have been made const. This may break some
existing code. Applications broken by this change should be modified.
The preferred solution is to refactor the code to avoid the use of these
deprecated functions. Failing this the code should be modified to use a
const pointer instead. The EVP_PKEY_get1_RSA(3), EVP_PKEY_get1_DSA(3),
EVP_PKEY_get1_EC_KEY(3) and EVP_PKEY_get1_DH(3) functions continue to
return a non-const pointer to enable them to be "freed". However they
should also be treated as read-only.
The public key check has moved from EVP_PKEY_derive() to
EVP_PKEY_derive_set_peer()
This may mean result in an error in EVP_PKEY_derive_set_peer(3) rather
than during EVP_PKEY_derive(3). To disable this check use
EVP_PKEY_derive_set_peer_ex(dh, peer, 0).
The print format has cosmetic changes for some functions
The output from numerous "printing" functions such as
X509_signature_print(3), X509_print_ex(3), X509_CRL_print_ex(3), and
other similar functions has been amended such that there may be cosmetic
differences between the output observed in 1.1.1 and 3.0. This also
applies to the -text output from the openssl x509 and openssl crl
applications.
Interactive mode from the openssl program has been removed
From now on, running it without arguments is equivalent to openssl help.
The error return values from some control calls (ctrl) have changed
One significant change is that controls which used to return -2 for
invalid inputs, now return -1 indicating a generic error condition
instead.
DH and DHX key types have different settable parameters
Previously (in 1.1.1) these conflicting parameters were allowed, but
will now result in errors. See EVP_PKEY-DH(7) for further details. This
affects the behaviour of openssl-genpkey(1) for DH parameter generation.
EVP_CIPHER_CTX_set_flags() ordering change
If using a cipher from a provider the EVP_CIPH_FLAG_LENGTH_BITS flag can
only be set after the cipher has been assigned to the cipher context.
See "FLAGS" in EVP_EncryptInit(3) for more information.
Validation of operation context parameters
Due to move of the implementation of cryptographic operations to the
providers, validation of various operation parameters can be postponed
until the actual operation is executed where previously it happened
immediately when an operation parameter was set.
For example when setting an unsupported curve with
EVP_PKEY_CTX_set_ec_paramgen_curve_nid() this function call will not
fail but later keygen operations with the EVP_PKEY_CTX will fail.
Removal of function code from the error codes
The function code part of the error code is now always set to 0. For
that reason the ERR_GET_FUNC() macro was removed. Applications must
resolve the error codes only using the library number and the reason
code.
ChaCha20-Poly1305 cipher does not allow a truncated IV length to be used
In OpenSSL 3.0 setting the IV length to any value other than 12 will
result in an error. Prior to OpenSSL 3.0 the ivlen could be smaller
that the required 12 byte length, using EVP_CIPHER_CTX_ctrl(ctx,
EVP_CRTL_AEAD_SET_IVLEN, ivlen, NULL). This resulted in an IV that had
leading zero padding.
Installation and Compilation
Please refer to the INSTALL.md file in the top of the distribution for
instructions on how to build and install OpenSSL 3.0. Please also refer
to the various platform specific NOTES files for your specific platform.
Upgrading from OpenSSL 1.1.1
Upgrading to OpenSSL 3.0 from OpenSSL 1.1.1 should be relatively
straight forward in most cases. The most likely area where you will
encounter problems is if you have used low level APIs in your code (as
discussed above). In that case you are likely to start seeing
deprecation warnings when compiling your application. If this happens
you have 3 options:
1. Ignore the warnings. They are just warnings. The deprecated
functions are still present and you may still use them. However be
aware that they may be removed from a future version of OpenSSL.
2. Suppress the warnings. Refer to your compiler documentation on how
to do this.
3. Remove your usage of the low level APIs. In this case you will need
to rewrite your code to use the high level APIs instead
Error code changes
As OpenSSL 3.0 provides a brand new Encoder/Decoder mechanism for
working with widely used file formats, application code that checks for
particular error reason codes on key loading failures might need an
update.
Password-protected keys may deserve special attention. If only some
errors are treated as an indicator that the user should be asked about
the password again, it's worth testing these scenarios and processing
the newly relevant codes.
There may be more cases to treat specially, depending on the calling
application code.
Upgrading from OpenSSL 1.0.2
Upgrading to OpenSSL 3.0 from OpenSSL 1.0.2 is likely to be
significantly more difficult. In addition to the issues discussed above
in the section about "Upgrading from OpenSSL 1.1.1", the main things to
be aware of are:
1. The build and installation procedure has changed significantly.
Check the file INSTALL.md in the top of the installation for
instructions on how to build and install OpenSSL for your platform.
Also read the various NOTES files in the same directory, as
applicable for your platform.
2. Many structures have been made opaque in OpenSSL 3.0.
The structure definitions have been removed from the public header
files and moved to internal header files. In practice this means
that you can no longer stack allocate some structures. Instead they
must be heap allocated through some function call (typically those
function names have a "_new" suffix to them). Additionally you must
use "setter" or "getter" functions to access the fields within those
structures.
For example code that previously looked like this:
EVP_MD_CTX md_ctx;
/* This line will now generate compiler errors */
EVP_MD_CTX_init(&md_ctx);
The code needs to be amended to look like this:
EVP_MD_CTX *md_ctx;
md_ctx = EVP_MD_CTX_new();
...
...
EVP_MD_CTX_free(md_ctx);
3. Support for TLSv1.3 has been added.
This has a number of implications for SSL/TLS applications. See the
TLS1.3 page <https://github.com/openssl/openssl/wiki/TLS1.3> for
further details.
More details about the breaking changes between OpenSSL versions 1.0.2
and 1.1.0 can be found on the OpenSSL 1.1.0 Changes page
<https://github.com/openssl/openssl/wiki/OpenSSL_1.1.0_Changes>.
Upgrading from the OpenSSL 2.0 FIPS Object Module
The OpenSSL 2.0 FIPS Object Module was a separate download that had to
be built separately and then integrated into your main OpenSSL 1.0.2
build. In OpenSSL 3.0 the FIPS support is fully integrated into the
mainline version of OpenSSL and is no longer a separate download. For
further information see "Completing the installation of the FIPS
Module".
The function calls FIPS_mode() and FIPS_mode_set() have been removed
from OpenSSL 3.0. You should rewrite your application to not use them.
See fips_module(7) and OSSL_PROVIDER-FIPS(7) for details.
Completing the installation of the FIPS Module
The FIPS Module will be built and installed automatically if FIPS
support has been configured. The current documentation can be found in
the README-FIPS <https://github.com/openssl/openssl/blob/master/README-
FIPS.md> file.
Programming
Applications written to work with OpenSSL 1.1.1 will mostly just work
with OpenSSL 3.0. However changes will be required if you want to take
advantage of some of the new features that OpenSSL 3.0 makes available.
In order to do that you need to understand some new concepts introduced
in OpenSSL 3.0. Read "Library contexts" in crypto(7) for further
information.
Library Context
A library context allows different components of a complex application
to each use a different library context and have different providers
loaded with different configuration settings. See "Library contexts" in
crypto(7) for further info.
If the user creates an OSSL_LIB_CTX via OSSL_LIB_CTX_new(3) then many
functions may need to be changed to pass additional parameters to handle
the library context.
Using a Library Context - Old functions that should be changed
If a library context is needed then all EVP_* digest functions that
return a const EVP_MD * such as EVP_sha256() should be replaced with a
call to EVP_MD_fetch(3). See "ALGORITHM FETCHING" in crypto(7).
If a library context is needed then all EVP_* cipher functions that
return a const EVP_CIPHER * such as EVP_aes_128_cbc() should be replaced
vith a call to EVP_CIPHER_fetch(3). See "ALGORITHM FETCHING" in
crypto(7).
Some functions can be passed an object that has already been set up with
a library context such as d2i_X509(3), d2i_X509_CRL(3), d2i_X509_REQ(3)
and d2i_X509_PUBKEY(3). If NULL is passed instead then the created
object will be set up with the default library context. Use
X509_new_ex(3), X509_CRL_new_ex(3), X509_REQ_new_ex(3) and
X509_PUBKEY_new_ex(3) if a library context is required.
All functions listed below with a NAME have a replacement function
NAME_ex that takes OSSL_LIB_CTX as an additional argument. Functions
that have other mappings are listed along with the respective name.
• ASN1_item_new(3), ASN1_item_d2i(3), ASN1_item_d2i_fp(3),
ASN1_item_d2i_bio(3), ASN1_item_sign(3) and ASN1_item_verify(3)
• BIO_new(3)
• b2i_RSA_PVK_bio() and i2b_PVK_bio()
• BN_CTX_new(3) and BN_CTX_secure_new(3)
• CMS_AuthEnvelopedData_create(3), CMS_ContentInfo_new(3),
CMS_data_create(3), CMS_digest_create(3),
CMS_EncryptedData_encrypt(3), CMS_encrypt(3),
CMS_EnvelopedData_create(3), CMS_ReceiptRequest_create0(3) and
CMS_sign(3)
• CONF_modules_load_file(3)
• CTLOG_new(3), CTLOG_new_from_base64(3) and CTLOG_STORE_new(3)
• CT_POLICY_EVAL_CTX_new(3)
• d2i_AutoPrivateKey(3), d2i_PrivateKey(3) and d2i_PUBKEY(3)
• d2i_PrivateKey_bio(3) and d2i_PrivateKey_fp(3)
Use d2i_PrivateKey_ex_bio(3) and d2i_PrivateKey_ex_fp(3)
• EC_GROUP_new(3)
Use EC_GROUP_new_by_curve_name_ex(3) or EC_GROUP_new_from_params(3).
• EVP_DigestSignInit(3) and EVP_DigestVerifyInit(3)
• EVP_PBE_CipherInit(3), EVP_PBE_find(3) and EVP_PBE_scrypt(3)
• PKCS5_PBE_keyivgen(3)
• EVP_PKCS82PKEY(3)
• EVP_PKEY_CTX_new_id(3)
Use EVP_PKEY_CTX_new_from_name(3)
• EVP_PKEY_derive_set_peer(3), EVP_PKEY_new_raw_private_key(3) and
EVP_PKEY_new_raw_public_key(3)
• EVP_SignFinal(3) and EVP_VerifyFinal(3)
• NCONF_new(3)
• OCSP_RESPID_match(3) and OCSP_RESPID_set_by_key(3)
• OPENSSL_thread_stop(3)
• OSSL_STORE_open(3)
• PEM_read_bio_Parameters(3), PEM_read_bio_PrivateKey(3),
PEM_read_bio_PUBKEY(3), PEM_read_PrivateKey(3) and
PEM_read_PUBKEY(3)
• PEM_write_bio_PrivateKey(3), PEM_write_bio_PUBKEY(3),
PEM_write_PrivateKey(3) and PEM_write_PUBKEY(3)
• PEM_X509_INFO_read_bio(3) and PEM_X509_INFO_read(3)
• PKCS12_add_key(3), PKCS12_add_safe(3), PKCS12_add_safes(3),
PKCS12_create(3), PKCS12_decrypt_skey(3), PKCS12_init(3),
PKCS12_item_decrypt_d2i(3), PKCS12_item_i2d_encrypt(3),
PKCS12_key_gen_asc(3), PKCS12_key_gen_uni(3),
PKCS12_key_gen_utf8(3), PKCS12_pack_p7encdata(3),
PKCS12_pbe_crypt(3), PKCS12_PBE_keyivgen(3),
PKCS12_SAFEBAG_create_pkcs8_encrypt(3)
• PKCS5_pbe_set0_algor(3), PKCS5_pbe_set(3), PKCS5_pbe2_set_iv(3),
PKCS5_pbkdf2_set(3) and PKCS5_v2_scrypt_keyivgen(3)
• PKCS7_encrypt(3), PKCS7_new(3) and PKCS7_sign(3)
• PKCS8_decrypt(3), PKCS8_encrypt(3) and PKCS8_set0_pbe(3)
• RAND_bytes(3) and RAND_priv_bytes(3)
• SMIME_write_ASN1(3)
• SSL_load_client_CA_file(3)
• SSL_CTX_new(3)
• TS_RESP_CTX_new(3)
• X509_CRL_new(3)
• X509_load_cert_crl_file(3) and X509_load_cert_file(3)
• X509_LOOKUP_by_subject(3) and X509_LOOKUP_ctrl(3)
• X509_NAME_hash(3)
• X509_new(3)
• X509_REQ_new(3) and X509_REQ_verify(3)
• X509_STORE_CTX_new(3), X509_STORE_set_default_paths(3),
X509_STORE_load_file(3), X509_STORE_load_locations(3) and
X509_STORE_load_store(3)
New functions that use a Library context
The following functions can be passed a library context if required.
Passing NULL will use the default library context.
• BIO_new_from_core_bio(3)
• EVP_ASYM_CIPHER_fetch(3) and EVP_ASYM_CIPHER_do_all_provided(3)
• EVP_CIPHER_fetch(3) and EVP_CIPHER_do_all_provided(3)
• EVP_default_properties_enable_fips(3) and
EVP_default_properties_is_fips_enabled(3)
• EVP_KDF_fetch(3) and EVP_KDF_do_all_provided(3)
• EVP_KEM_fetch(3) and EVP_KEM_do_all_provided(3)
• EVP_KEYEXCH_fetch(3) and EVP_KEYEXCH_do_all_provided(3)
• EVP_KEYMGMT_fetch(3) and EVP_KEYMGMT_do_all_provided(3)
• EVP_MAC_fetch(3) and EVP_MAC_do_all_provided(3)
• EVP_MD_fetch(3) and EVP_MD_do_all_provided(3)
• EVP_PKEY_CTX_new_from_pkey(3)
• EVP_PKEY_Q_keygen(3)
• EVP_Q_mac(3) and EVP_Q_digest(3)
• EVP_RAND(3) and EVP_RAND_do_all_provided(3)
• EVP_set_default_properties(3)
• EVP_SIGNATURE_fetch(3) and EVP_SIGNATURE_do_all_provided(3)
• OSSL_CMP_CTX_new(3) and OSSL_CMP_SRV_CTX_new(3)
• OSSL_CRMF_ENCRYPTEDVALUE_get1_encCert(3)
• OSSL_CRMF_MSG_create_popo(3) and OSSL_CRMF_MSGS_verify_popo(3)
• OSSL_CRMF_pbm_new(3) and OSSL_CRMF_pbmp_new(3)
• OSSL_DECODER_CTX_add_extra(3) and OSSL_DECODER_CTX_new_for_pkey(3)
• OSSL_DECODER_fetch(3) and OSSL_DECODER_do_all_provided(3)
• OSSL_ENCODER_CTX_add_extra(3)
• OSSL_ENCODER_fetch(3) and OSSL_ENCODER_do_all_provided(3)
• OSSL_LIB_CTX_free(3), OSSL_LIB_CTX_load_config(3) and
OSSL_LIB_CTX_set0_default(3)
• OSSL_PROVIDER_add_builtin(3), OSSL_PROVIDER_available(3),
OSSL_PROVIDER_do_all(3), OSSL_PROVIDER_load(3),
OSSL_PROVIDER_set_default_search_path(3) and
OSSL_PROVIDER_try_load(3)
• OSSL_SELF_TEST_get_callback(3) and OSSL_SELF_TEST_set_callback(3)
• OSSL_STORE_attach(3)
• OSSL_STORE_LOADER_fetch(3) and OSSL_STORE_LOADER_do_all_provided(3)
• RAND_get0_primary(3), RAND_get0_private(3), RAND_get0_public(3),
RAND_set_DRBG_type(3) and RAND_set_seed_source_type(3)
Providers
Providers are described in detail here "Providers" in crypto(7). See
also "OPENSSL PROVIDERS" in crypto(7).
Fetching algorithms and property queries
Implicit and Explicit Fetching is described in detail here "ALGORITHM
FETCHING" in crypto(7).
Mapping EVP controls and flags to provider OSSL_PARAM(3) parameters
The existing functions for controls (such as EVP_CIPHER_CTX_ctrl(3)) and
manipulating flags (such as EVP_MD_CTX_set_flags(3))internally use
OSSL_PARAMS to pass information to/from provider objects. See
OSSL_PARAM(3) for additional information related to parameters.
For ciphers see "CONTROLS" in EVP_EncryptInit(3), "FLAGS" in
EVP_EncryptInit(3) and "PARAMETERS" in EVP_EncryptInit(3).
For digests see "CONTROLS" in EVP_DigestInit(3), "FLAGS" in
EVP_DigestInit(3) and "PARAMETERS" in EVP_DigestInit(3).
Deprecation of Low Level Functions
A significant number of APIs have been deprecated in OpenSSL 3.0. This
section describes some common categories of deprecations. See
"Deprecated function mappings" for the list of deprecated functions that
refer to these categories.
Providers are a replacement for engines and low-level method overrides
Any accessor that uses an ENGINE is deprecated (such as
EVP_PKEY_set1_engine()). Applications using engines should instead use
providers.
Before providers were added algorithms were overridden by changing the
methods used by algorithms. All these methods such as RSA_new_method()
and RSA_meth_new() are now deprecated and can be replaced by using
providers instead.
Deprecated i2d and d2i functions for low-level key types
Any i2d and d2i functions such as d2i_DHparams() that take a low-level
key type have been deprecated. Applications should instead use the
OSSL_DECODER(3) and OSSL_ENCODER(3) APIs to read and write files. See
"Migration" in d2i_RSAPrivateKey(3) for further details.
Deprecated low-level key object getters and setters
Applications that set or get low-level key objects (such as
EVP_PKEY_set1_DH() or EVP_PKEY_get0()) should instead use the
OSSL_ENCODER (See OSSL_ENCODER_to_bio(3)) or OSSL_DECODER (See
OSSL_DECODER_from_bio(3)) APIs, or alternatively use
EVP_PKEY_fromdata(3) or EVP_PKEY_todata(3).
Deprecated low-level key parameter getters
Functions that access low-level objects directly such as RSA_get0_n(3)
are now deprecated. Applications should use one of:
EVP_PKEY_get_bn_param(3), EVP_PKEY_get_int_param(3),
EVP_PKEY_get_size_t_param(3), EVP_PKEY_get_utf8_string_param(3),
EVP_PKEY_get_octet_string_param(3), or EVP_PKEY_get_params(3), to access
fields from an EVP_PKEY. Gettable parameters are listed in: "Common RSA
parameters" in EVP_PKEY-RSA(7), "Common EC parameters" in
EVP_PKEY-EC(7), "DSA parameters" in EVP_PKEY-DSA(7), "DH parameters" in
EVP_PKEY-DH(7), "FFC parameters" in EVP_PKEY-FFC(7), "Common X25519,
X448, ED25519 and ED448 parameters" in EVP_PKEY-X25519(7), "Common
parameters" in EVP_PKEY-ML-DSA(7), and "Common parameters" in
EVP_PKEY-ML-KEM(7). Applications may also use EVP_PKEY_todata(3) to
return all fields.
Deprecated low-level key parameter setters
Functions that access low-level objects directly such as
RSA_set0_crt_params(3) are now deprecated. Applications should use
EVP_PKEY_fromdata(3) to create new keys from user provided key data.
Keys should be immutable once they are created, so if required the user
may use EVP_PKEY_todata(3), OSSL_PARAM_merge(3), and
EVP_PKEY_fromdata(3) to create a modified key. See "Examples" in
EVP_PKEY-DH(7) for more information. See "Deprecated low-level key
generation functions" for information on generating a key using
parameters.
Deprecated low-level object creation
Low-level objects were created using methods such as RSA_new(3),
RSA_up_ref(3) and RSA_free(3). Applications should instead use the high-
level EVP_PKEY APIs, e.g. EVP_PKEY_new(3), EVP_PKEY_up_ref(3) and
EVP_PKEY_free(3). See also EVP_PKEY_CTX_new_from_name(3) and
EVP_PKEY_CTX_new_from_pkey(3).
EVP_PKEYs may be created in a variety of ways: See also "Deprecated low-
level key generation functions", "Deprecated low-level key reading and
writing functions" and "Deprecated low-level key parameter setters".
Deprecated low-level encryption functions
Low-level encryption functions such as AES_encrypt(3) and AES_decrypt(3)
have been informally discouraged from use for a long time. Applications
should instead use the high level EVP APIs EVP_EncryptInit_ex(3),
EVP_EncryptUpdate(3), and EVP_EncryptFinal_ex(3) or
EVP_DecryptInit_ex(3), EVP_DecryptUpdate(3) and EVP_DecryptFinal_ex(3).
Deprecated low-level digest functions
Use of low-level digest functions such as SHA1_Init(3) have been
informally discouraged from use for a long time. Applications should
instead use the high level EVP APIs EVP_DigestInit_ex(3),
EVP_DigestUpdate(3) and EVP_DigestFinal_ex(3), or the quick one-shot
EVP_Q_digest(3).
Note that the functions SHA1(3), SHA224(3), SHA256(3), SHA384(3) and
SHA512(3) have changed to macros that use EVP_Q_digest(3).
Deprecated low-level signing functions
Use of low-level signing functions such as DSA_sign(3) have been
informally discouraged for a long time. Instead applications should use
EVP_DigestSign(3) and EVP_DigestVerify(3). See also
EVP_SIGNATURE-RSA(7), EVP_SIGNATURE-DSA(7), EVP_SIGNATURE-ECDSA(7) and
EVP_SIGNATURE-ED25519(7).
Deprecated low-level MAC functions
Low-level mac functions such as CMAC_Init(3) are deprecated.
Applications should instead use the new EVP_MAC(3) interface, using
EVP_MAC_CTX_new(3), EVP_MAC_CTX_free(3), EVP_MAC_init(3),
EVP_MAC_update(3) and EVP_MAC_final(3) or the single-shot MAC function
EVP_Q_mac(3). See EVP_MAC(3), EVP_MAC-HMAC(7), EVP_MAC-CMAC(7),
EVP_MAC-GMAC(7), EVP_MAC-KMAC(7), EVP_MAC-BLAKE2(7), EVP_MAC-Poly1305(7)
and EVP_MAC-Siphash(7) for additional information.
Note that the one-shot method HMAC() is still available for
compatibility purposes, but this can also be replaced by using EVP_Q_MAC
if a library context is required.
Deprecated low-level validation functions
Low-level validation functions such as DH_check(3) have been informally
discouraged from use for a long time. Applications should instead use
the high-level EVP_PKEY APIs such as EVP_PKEY_check(3),
EVP_PKEY_param_check(3), EVP_PKEY_param_check_quick(3),
EVP_PKEY_public_check(3), EVP_PKEY_public_check_quick(3),
EVP_PKEY_private_check(3), and EVP_PKEY_pairwise_check(3).
Deprecated low-level key exchange functions
Many low-level functions have been informally discouraged from use for a
long time. Applications should instead use EVP_PKEY_derive(3). See
EVP_KEYEXCH-DH(7), EVP_KEYEXCH-ECDH(7) and EVP_KEYEXCH-X25519(7).
Deprecated low-level key generation functions
Many low-level functions have been informally discouraged from use for a
long time. Applications should instead use EVP_PKEY_keygen_init(3) and
EVP_PKEY_generate(3) as described in EVP_PKEY-DSA(7), EVP_PKEY-DH(7),
EVP_PKEY-RSA(7), EVP_PKEY-EC(7) and EVP_PKEY-X25519(7). The 'quick'
one-shot function EVP_PKEY_Q_keygen(3) and macros for the most common
cases: <EVP_RSA_gen(3)> and EVP_EC_gen(3) may also be used.
Deprecated low-level key reading and writing functions
Use of low-level objects (such as DSA) has been informally discouraged
from use for a long time. Functions to read and write these low-level
objects (such as PEM_read_DSA_PUBKEY()) should be replaced. Applications
should instead use OSSL_ENCODER_to_bio(3) and OSSL_DECODER_from_bio(3).
Deprecated low-level key printing functions
Use of low-level objects (such as DSA) has been informally discouraged
from use for a long time. Functions to print these low-level objects
such as DSA_print() should be replaced with the equivalent EVP_PKEY
functions. Application should use one of EVP_PKEY_print_public(3),
EVP_PKEY_print_private(3), EVP_PKEY_print_params(3),
EVP_PKEY_print_public_fp(3), EVP_PKEY_print_private_fp(3) or
EVP_PKEY_print_params_fp(3). Note that internally these use
OSSL_ENCODER_to_bio(3) and OSSL_DECODER_from_bio(3).
Deprecated function mappings
The following functions have been deprecated in 3.0.
• AES_bi_ige_encrypt() and AES_ige_encrypt()
There is no replacement for the IGE functions. New code should not
use these modes. These undocumented functions were never integrated
into the EVP layer. They implemented the AES Infinite Garble
Extension (IGE) mode and AES Bi-directional IGE mode. These modes
were never formally standardised and usage of these functions is
believed to be very small. In particular AES_bi_ige_encrypt() has a
known bug. It accepts 2 AES keys, but only one is ever used. The
security implications are believed to be minimal, but this issue was
never fixed for backwards compatibility reasons.
• AES_encrypt(), AES_decrypt(), AES_set_encrypt_key(),
AES_set_decrypt_key(), AES_cbc_encrypt(), AES_cfb128_encrypt(),
AES_cfb1_encrypt(), AES_cfb8_encrypt(), AES_ecb_encrypt(),
AES_ofb128_encrypt()
• AES_unwrap_key(), AES_wrap_key()
See "Deprecated low-level encryption functions"
• AES_options()
There is no replacement. It returned a string indicating if the AES
code was unrolled.
• ASN1_digest(), ASN1_sign(), ASN1_verify()
There are no replacements. These old functions are not used, and
could be disabled with the macro NO_ASN1_OLD since OpenSSL 0.9.7.
• ASN1_STRING_length_set()
Use ASN1_STRING_set(3) or ASN1_STRING_set0(3) instead. This was a
potentially unsafe function that could change the bounds of a
previously passed in pointer.
• BF_encrypt(), BF_decrypt(), BF_set_key(), BF_cbc_encrypt(),
BF_cfb64_encrypt(), BF_ecb_encrypt(), BF_ofb64_encrypt()
See "Deprecated low-level encryption functions". The Blowfish
algorithm has been moved to the Legacy Provider.
• BF_options()
There is no replacement. This option returned a constant string.
• BIO_get_callback(), BIO_set_callback(), BIO_debug_callback()
Use the respective non-deprecated _ex() functions.
• BN_is_prime_ex(), BN_is_prime_fasttest_ex()
Use BN_check_prime(3) which avoids possible misuse and always uses
at least 64 rounds of the Miller-Rabin primality test.
• BN_pseudo_rand(), BN_pseudo_rand_range()
Use BN_rand(3) and BN_rand_range(3).
• BN_X931_derive_prime_ex(), BN_X931_generate_prime_ex(),
BN_X931_generate_Xpq()
There are no replacements for these low-level functions. They were
used internally by RSA_X931_derive_ex() and
RSA_X931_generate_key_ex() which are also deprecated. Use
EVP_PKEY_keygen(3) instead.
• Camellia_encrypt(), Camellia_decrypt(), Camellia_set_key(),
Camellia_cbc_encrypt(), Camellia_cfb128_encrypt(),
Camellia_cfb1_encrypt(), Camellia_cfb8_encrypt(),
Camellia_ctr128_encrypt(), Camellia_ecb_encrypt(),
Camellia_ofb128_encrypt()
See "Deprecated low-level encryption functions".
• CAST_encrypt(), CAST_decrypt(), CAST_set_key(), CAST_cbc_encrypt(),
CAST_cfb64_encrypt(), CAST_ecb_encrypt(), CAST_ofb64_encrypt()
See "Deprecated low-level encryption functions". The CAST algorithm
has been moved to the Legacy Provider.
• CMAC_CTX_new(), CMAC_CTX_cleanup(), CMAC_CTX_copy(),
CMAC_CTX_free(), CMAC_CTX_get0_cipher_ctx()
See "Deprecated low-level MAC functions".
• CMAC_Init(), CMAC_Update(), CMAC_Final(), CMAC_resume()
See "Deprecated low-level MAC functions".
• CRYPTO_mem_ctrl(), CRYPTO_mem_debug_free(),
CRYPTO_mem_debug_malloc(), CRYPTO_mem_debug_pop(),
CRYPTO_mem_debug_push(), CRYPTO_mem_debug_realloc(),
CRYPTO_mem_leaks(), CRYPTO_mem_leaks_cb(), CRYPTO_mem_leaks_fp(),
CRYPTO_set_mem_debug()
Memory-leak checking has been deprecated in favor of more modern
development tools, such as compiler memory and leak sanitizers or
Valgrind.
• CRYPTO_cts128_encrypt_block(), CRYPTO_cts128_encrypt(),
CRYPTO_cts128_decrypt_block(), CRYPTO_cts128_decrypt(),
CRYPTO_nistcts128_encrypt_block(), CRYPTO_nistcts128_encrypt(),
CRYPTO_nistcts128_decrypt_block(), CRYPTO_nistcts128_decrypt()
Use the higher level functions EVP_CipherInit_ex2(),
EVP_CipherUpdate() and EVP_CipherFinal_ex() instead. See the
"cts_mode" parameter in "Gettable and Settable EVP_CIPHER_CTX
parameters" in EVP_EncryptInit(3). See "EXAMPLES" in
EVP_EncryptInit(3) for a AES-256-CBC-CTS example.
• d2i_DHparams(), d2i_DHxparams(), d2i_DSAparams(),
d2i_DSAPrivateKey(), d2i_DSAPrivateKey_bio(),
d2i_DSAPrivateKey_fp(), d2i_DSA_PUBKEY(), d2i_DSA_PUBKEY_bio(),
d2i_DSA_PUBKEY_fp(), d2i_DSAPublicKey(), d2i_ECParameters(),
d2i_ECPrivateKey(), d2i_ECPrivateKey_bio(), d2i_ECPrivateKey_fp(),
d2i_EC_PUBKEY(), d2i_EC_PUBKEY_bio(), d2i_EC_PUBKEY_fp(),
d2i_RSAPrivateKey(), d2i_RSAPrivateKey_bio(),
d2i_RSAPrivateKey_fp(), d2i_RSA_PUBKEY(), d2i_RSA_PUBKEY_bio(),
d2i_RSA_PUBKEY_fp(), d2i_RSAPublicKey(), d2i_RSAPublicKey_bio(),
d2i_RSAPublicKey_fp()
See "Deprecated i2d and d2i functions for low-level key types"
• o2i_ECPublicKey()
Use EVP_PKEY_set1_encoded_public_key(3). See "Deprecated low-level
key parameter setters"
• DES_crypt(), DES_fcrypt(), DES_encrypt1(), DES_encrypt2(),
DES_encrypt3(), DES_decrypt3(), DES_ede3_cbc_encrypt(),
DES_ede3_cfb64_encrypt(),
DES_ede3_cfb_encrypt(),DES_ede3_ofb64_encrypt(), DES_ecb_encrypt(),
DES_ecb3_encrypt(), DES_ofb64_encrypt(), DES_ofb_encrypt(),
DES_cfb64_encrypt DES_cfb_encrypt(), DES_cbc_encrypt(),
DES_ncbc_encrypt(), DES_pcbc_encrypt(), DES_xcbc_encrypt(),
DES_cbc_cksum(), DES_quad_cksum(), DES_check_key_parity(),
DES_is_weak_key(), DES_key_sched(), DES_options(), DES_random_key(),
DES_set_key(), DES_set_key_checked(), DES_set_key_unchecked(),
DES_set_odd_parity(), DES_string_to_2keys(), DES_string_to_key()
See "Deprecated low-level encryption functions". Algorithms for
"DESX-CBC", "DES-ECB", "DES-CBC", "DES-OFB", "DES-CFB", "DES-CFB1"
and "DES-CFB8" have been moved to the Legacy Provider.
• DH_bits(), DH_security_bits(), DH_size()
Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and
EVP_PKEY_get_size(3).
• DH_check(), DH_check_ex(), DH_check_params(), DH_check_params_ex(),
DH_check_pub_key(), DH_check_pub_key_ex()
See "Deprecated low-level validation functions"
• DH_clear_flags(), DH_test_flags(), DH_set_flags()
The DH_FLAG_CACHE_MONT_P flag has been deprecated without
replacement. The DH_FLAG_TYPE_DH and DH_FLAG_TYPE_DHX have been
deprecated. Use EVP_PKEY_is_a() to determine the type of a key.
There is no replacement for setting these flags.
• DH_compute_key() DH_compute_key_padded()
See "Deprecated low-level key exchange functions".
• DH_new(), DH_new_by_nid(), DH_free(), DH_up_ref()
See "Deprecated low-level object creation"
• DH_generate_key(), DH_generate_parameters_ex()
See "Deprecated low-level key generation functions".
• DH_get0_pqg(), DH_get0_p(), DH_get0_q(), DH_get0_g(), DH_get0_key(),
DH_get0_priv_key(), DH_get0_pub_key(), DH_get_length(), DH_get_nid()
See "Deprecated low-level key parameter getters"
• DH_get_1024_160(), DH_get_2048_224(), DH_get_2048_256()
Applications should instead set the OSSL_PKEY_PARAM_GROUP_NAME as
specified in "DH parameters" in EVP_PKEY-DH(7)) to one of
"dh_1024_160", "dh_2048_224" or "dh_2048_256" when generating a DH
key.
• DH_KDF_X9_42()
Applications should use EVP_PKEY_CTX_set_dh_kdf_type(3) instead.
• DH_get_default_method(), DH_get0_engine(), DH_meth_*(),
DH_new_method(), DH_OpenSSL(), DH_get_ex_data(),
DH_set_default_method(), DH_set_method(), DH_set_ex_data()
See "Providers are a replacement for engines and low-level method
overrides"
• DHparams_print(), DHparams_print_fp()
See "Deprecated low-level key printing functions"
• DH_set0_key(), DH_set0_pqg(), DH_set_length()
See "Deprecated low-level key parameter setters"
• DSA_bits(), DSA_security_bits(), DSA_size()
Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and
EVP_PKEY_get_size(3).
• DHparams_dup(), DSA_dup_DH()
There is no direct replacement. Applications may use
EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead.
• DSA_generate_key(), DSA_generate_parameters_ex()
See "Deprecated low-level key generation functions".
• DSA_get0_engine(), DSA_get_default_method(), DSA_get_ex_data(),
DSA_get_method(), DSA_meth_*(), DSA_new_method(), DSA_OpenSSL(),
DSA_set_default_method(), DSA_set_ex_data(), DSA_set_method()
See "Providers are a replacement for engines and low-level method
overrides".
• DSA_get0_p(), DSA_get0_q(), DSA_get0_g(), DSA_get0_pqg(),
DSA_get0_key(), DSA_get0_priv_key(), DSA_get0_pub_key()
See "Deprecated low-level key parameter getters".
• DSA_new(), DSA_free(), DSA_up_ref()
See "Deprecated low-level object creation"
• DSAparams_dup()
There is no direct replacement. Applications may use
EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead.
• DSAparams_print(), DSAparams_print_fp(), DSA_print(), DSA_print_fp()
See "Deprecated low-level key printing functions"
• DSA_set0_key(), DSA_set0_pqg()
See "Deprecated low-level key parameter setters"
• DSA_set_flags(), DSA_clear_flags(), DSA_test_flags()
The DSA_FLAG_CACHE_MONT_P flag has been deprecated without
replacement.
• DSA_sign(), DSA_do_sign(), DSA_sign_setup(), DSA_verify(),
DSA_do_verify()
See "Deprecated low-level signing functions".
• ECDH_compute_key()
See "Deprecated low-level key exchange functions".
• ECDH_KDF_X9_62()
Applications may either set this using the helper function
EVP_PKEY_CTX_set_ecdh_kdf_type(3) or by setting an OSSL_PARAM(3)
using the "kdf-type" as shown in "EXAMPLES" in EVP_KEYEXCH-ECDH(7)
• ECDSA_sign(), ECDSA_sign_ex(), ECDSA_sign_setup(), ECDSA_do_sign(),
ECDSA_do_sign_ex(), ECDSA_verify(), ECDSA_do_verify()
See "Deprecated low-level signing functions".
• ECDSA_size()
Applications should use EVP_PKEY_get_size(3).
• EC_GF2m_simple_method(), EC_GFp_mont_method(), EC_GFp_nist_method(),
EC_GFp_nistp224_method(), EC_GFp_nistp256_method(),
EC_GFp_nistp521_method(), EC_GFp_simple_method()
There are no replacements for these functions. Applications should
rely on the library automatically assigning a suitable method
internally when an EC_GROUP is constructed.
• EC_GROUP_clear_free()
Use EC_GROUP_free(3) instead.
• EC_GROUP_get_curve_GF2m(), EC_GROUP_get_curve_GFp(),
EC_GROUP_set_curve_GF2m(), EC_GROUP_set_curve_GFp()
Applications should use EC_GROUP_get_curve(3) and
EC_GROUP_set_curve(3).
• EC_GROUP_have_precompute_mult(), EC_GROUP_precompute_mult(),
EC_KEY_precompute_mult()
These functions are not widely used. Applications should instead
switch to named curves which OpenSSL has hardcoded lookup tables
for.
• EC_GROUP_new(), EC_GROUP_method_of(), EC_POINT_method_of()
EC_METHOD is now an internal-only concept and a suitable EC_METHOD
is assigned internally without application intervention. Users of
EC_GROUP_new() should switch to a different suitable constructor.
• EC_KEY_can_sign()
Applications should use EVP_PKEY_can_sign(3) instead.
• EC_KEY_check_key()
See "Deprecated low-level validation functions"
• EC_KEY_set_flags(), EC_KEY_get_flags(), EC_KEY_clear_flags()
See "Common EC parameters" in EVP_PKEY-EC(7) which handles flags as
separate parameters for OSSL_PKEY_PARAM_EC_POINT_CONVERSION_FORMAT,
OSSL_PKEY_PARAM_EC_GROUP_CHECK_TYPE, OSSL_PKEY_PARAM_EC_ENCODING,
OSSL_PKEY_PARAM_USE_COFACTOR_ECDH and
OSSL_PKEY_PARAM_EC_INCLUDE_PUBLIC. See also "EXAMPLES" in
EVP_PKEY-EC(7)
• EC_KEY_dup(), EC_KEY_copy()
There is no direct replacement. Applications may use
EVP_PKEY_copy_parameters(3) and EVP_PKEY_dup(3) instead.
• EC_KEY_decoded_from_explicit_params()
There is no replacement.
• EC_KEY_generate_key()
See "Deprecated low-level key generation functions".
• EC_KEY_get0_group(), EC_KEY_get0_private_key(),
EC_KEY_get0_public_key(), EC_KEY_get_conv_form(),
EC_KEY_get_enc_flags()
See "Deprecated low-level key parameter getters".
• EC_KEY_get0_engine(), EC_KEY_get_default_method(),
EC_KEY_get_method(), EC_KEY_new_method(), EC_KEY_get_ex_data(),
EC_KEY_OpenSSL(), EC_KEY_set_ex_data(), EC_KEY_set_default_method(),
EC_KEY_METHOD_*(), EC_KEY_set_method()
See "Providers are a replacement for engines and low-level method
overrides"
• EC_METHOD_get_field_type()
Use EC_GROUP_get_field_type(3) instead. See "Providers are a
replacement for engines and low-level method overrides"
• EC_KEY_key2buf(), EC_KEY_oct2key(), EC_KEY_oct2priv(),
EC_KEY_priv2buf(), EC_KEY_priv2oct()
There are no replacements for these.
• EC_KEY_new(), EC_KEY_new_by_curve_name(), EC_KEY_free(),
EC_KEY_up_ref()
See "Deprecated low-level object creation"
• EC_KEY_print(), EC_KEY_print_fp()
See "Deprecated low-level key printing functions"
• EC_KEY_set_asn1_flag(), EC_KEY_set_conv_form(),
EC_KEY_set_enc_flags()
See "Deprecated low-level key parameter setters".
• EC_KEY_set_group(), EC_KEY_set_private_key(),
EC_KEY_set_public_key(), EC_KEY_set_public_key_affine_coordinates()
See "Deprecated low-level key parameter setters".
• ECParameters_print(), ECParameters_print_fp(),
ECPKParameters_print(), ECPKParameters_print_fp()
See "Deprecated low-level key printing functions"
• EC_POINT_bn2point(), EC_POINT_point2bn()
These functions were not particularly useful, since EC point
serialization formats are not individual big-endian integers.
• EC_POINT_get_affine_coordinates_GF2m(),
EC_POINT_get_affine_coordinates_GFp(),
EC_POINT_set_affine_coordinates_GF2m(),
EC_POINT_set_affine_coordinates_GFp()
Applications should use EC_POINT_get_affine_coordinates(3) and
EC_POINT_set_affine_coordinates(3) instead.
• EC_POINT_get_Jprojective_coordinates_GFp(),
EC_POINT_set_Jprojective_coordinates_GFp()
These functions are not widely used. Applications should instead use
the EC_POINT_set_affine_coordinates(3) and
EC_POINT_get_affine_coordinates(3) functions.
• EC_POINT_make_affine(), EC_POINTs_make_affine()
There is no replacement. These functions were not widely used, and
OpenSSL automatically performs this conversion when needed.
• EC_POINT_set_compressed_coordinates_GF2m(),
EC_POINT_set_compressed_coordinates_GFp()
Applications should use EC_POINT_set_compressed_coordinates(3)
instead.
• EC_POINTs_mul()
This function is not widely used. Applications should instead use
the EC_POINT_mul(3) function.
• ENGINE_*()
All engine functions are deprecated. An engine should be rewritten
as a provider. See "Providers are a replacement for engines and
low-level method overrides".
• ERR_load_*(), ERR_func_error_string(), ERR_get_error_line(),
ERR_get_error_line_data(), ERR_get_state()
OpenSSL now loads error strings automatically so these functions are
not needed.
• ERR_peek_error_line_data(), ERR_peek_last_error_line_data()
The new functions are ERR_peek_error_func(3),
ERR_peek_last_error_func(3), ERR_peek_error_data(3),
ERR_peek_last_error_data(3), ERR_get_error_all(3),
ERR_peek_error_all(3) and ERR_peek_last_error_all(3). Applications
should use ERR_get_error_all(3), or pick information with ERR_peek
functions and finish off with getting the error code by using
ERR_get_error(3).
• EVP_CIPHER_CTX_iv(), EVP_CIPHER_CTX_iv_noconst(),
EVP_CIPHER_CTX_original_iv()
Applications should instead use EVP_CIPHER_CTX_get_updated_iv(3),
EVP_CIPHER_CTX_get_updated_iv(3) and
EVP_CIPHER_CTX_get_original_iv(3) respectively. See
EVP_CIPHER_CTX_get_original_iv(3) for further information.
• EVP_CIPHER_meth_*(), EVP_MD_CTX_set_update_fn(),
EVP_MD_CTX_update_fn(), EVP_MD_meth_*()
See "Providers are a replacement for engines and low-level method
overrides".
• EVP_PKEY_CTRL_PKCS7_ENCRYPT(), EVP_PKEY_CTRL_PKCS7_DECRYPT(),
EVP_PKEY_CTRL_PKCS7_SIGN(), EVP_PKEY_CTRL_CMS_ENCRYPT(),
EVP_PKEY_CTRL_CMS_DECRYPT(), and EVP_PKEY_CTRL_CMS_SIGN()
These control operations are not invoked by the OpenSSL library
anymore and are replaced by direct checks of the key operation
against the key type when the operation is initialized.
• EVP_PKEY_CTX_get0_dh_kdf_ukm(), EVP_PKEY_CTX_get0_ecdh_kdf_ukm()
See the "kdf-ukm" item in "DH key exchange parameters" in
EVP_KEYEXCH-DH(7) and "ECDH Key Exchange parameters" in
EVP_KEYEXCH-ECDH(7). These functions are obsolete and should not be
required.
• EVP_PKEY_CTX_set_rsa_keygen_pubexp()
Applications should use EVP_PKEY_CTX_set1_rsa_keygen_pubexp(3)
instead.
• EVP_PKEY_cmp(), EVP_PKEY_cmp_parameters()
Applications should use EVP_PKEY_eq(3) and EVP_PKEY_parameters_eq(3)
instead. See EVP_PKEY_copy_parameters(3) for further details.
• EVP_PKEY_encrypt_old(), EVP_PKEY_decrypt_old(),
Applications should use EVP_PKEY_encrypt_init(3) and
EVP_PKEY_encrypt(3) or EVP_PKEY_decrypt_init(3) and
EVP_PKEY_decrypt(3) instead.
• EVP_PKEY_get0()
This function returns NULL if the key comes from a provider.
• EVP_PKEY_get0_DH(), EVP_PKEY_get0_DSA(), EVP_PKEY_get0_EC_KEY(),
EVP_PKEY_get0_RSA(), EVP_PKEY_get1_DH(), EVP_PKEY_get1_DSA(),
EVP_PKEY_get1_EC_KEY and EVP_PKEY_get1_RSA(), EVP_PKEY_get0_hmac(),
EVP_PKEY_get0_poly1305(), EVP_PKEY_get0_siphash()
See "Functions that return an internal key should be treated as read
only".
• EVP_PKEY_meth_*()
See "Providers are a replacement for engines and low-level method
overrides".
• EVP_PKEY_new_CMAC_key()
See "Deprecated low-level MAC functions".
• EVP_PKEY_assign(), EVP_PKEY_set1_DH(), EVP_PKEY_set1_DSA(),
EVP_PKEY_set1_EC_KEY(), EVP_PKEY_set1_RSA()
See "Deprecated low-level key object getters and setters"
• EVP_PKEY_set1_tls_encodedpoint() EVP_PKEY_get1_tls_encodedpoint()
These functions were previously used by libssl to set or get an
encoded public key into/from an EVP_PKEY object. With OpenSSL 3.0
these are replaced by the more generic functions
EVP_PKEY_set1_encoded_public_key(3) and
EVP_PKEY_get1_encoded_public_key(3). The old versions have been
converted to deprecated macros that just call the new functions.
• EVP_PKEY_set1_engine(), EVP_PKEY_get0_engine()
See "Providers are a replacement for engines and low-level method
overrides".
• EVP_PKEY_set_alias_type()
This function has been removed. There is no replacement. See
"EVP_PKEY_set_alias_type() method has been removed"
• HMAC_Init_ex(), HMAC_Update(), HMAC_Final(), HMAC_size()
See "Deprecated low-level MAC functions".
• HMAC_CTX_new(), HMAC_CTX_free(), HMAC_CTX_copy(), HMAC_CTX_reset(),
HMAC_CTX_set_flags(), HMAC_CTX_get_md()
See "Deprecated low-level MAC functions".
• i2d_DHparams(), i2d_DHxparams()
See "Deprecated low-level key reading and writing functions" and
"Migration" in d2i_RSAPrivateKey(3)
• i2d_DSAparams(), i2d_DSAPrivateKey(), i2d_DSAPrivateKey_bio(),
i2d_DSAPrivateKey_fp(), i2d_DSA_PUBKEY(), i2d_DSA_PUBKEY_bio(),
i2d_DSA_PUBKEY_fp(), i2d_DSAPublicKey()
See "Deprecated low-level key reading and writing functions" and
"Migration" in d2i_RSAPrivateKey(3)
• i2d_ECParameters(), i2d_ECPrivateKey(), i2d_ECPrivateKey_bio(),
i2d_ECPrivateKey_fp(), i2d_EC_PUBKEY(), i2d_EC_PUBKEY_bio(),
i2d_EC_PUBKEY_fp()
See "Deprecated low-level key reading and writing functions" and
"Migration" in d2i_RSAPrivateKey(3)
• i2o_ECPublicKey()
Use EVP_PKEY_get1_encoded_public_key(3). See "Deprecated low-level
key parameter getters"
• i2d_RSAPrivateKey(), i2d_RSAPrivateKey_bio(),
i2d_RSAPrivateKey_fp(), i2d_RSA_PUBKEY(), i2d_RSA_PUBKEY_bio(),
i2d_RSA_PUBKEY_fp(), i2d_RSAPublicKey(), i2d_RSAPublicKey_bio(),
i2d_RSAPublicKey_fp()
See "Deprecated low-level key reading and writing functions" and
"Migration" in d2i_RSAPrivateKey(3)
• IDEA_encrypt(), IDEA_set_decrypt_key(), IDEA_set_encrypt_key(),
IDEA_cbc_encrypt(), IDEA_cfb64_encrypt(), IDEA_ecb_encrypt(),
IDEA_ofb64_encrypt()
See "Deprecated low-level encryption functions". IDEA has been
moved to the Legacy Provider.
• IDEA_options()
There is no replacement. This function returned a constant string.
• MD2(), MD2_Init(), MD2_Update(), MD2_Final()
See "Deprecated low-level encryption functions". MD2 has been moved
to the Legacy Provider.
• MD2_options()
There is no replacement. This function returned a constant string.
• MD4(), MD4_Init(), MD4_Update(), MD4_Final(), MD4_Transform()
See "Deprecated low-level encryption functions". MD4 has been moved
to the Legacy Provider.
• MDC2(), MDC2_Init(), MDC2_Update(), MDC2_Final()
See "Deprecated low-level encryption functions". MDC2 has been
moved to the Legacy Provider.
• MD5(), MD5_Init(), MD5_Update(), MD5_Final(), MD5_Transform()
See "Deprecated low-level encryption functions".
• NCONF_WIN32()
This undocumented function has no replacement. See "HISTORY" in
config(5) for more details.
• OCSP_parse_url()
Use OSSL_HTTP_parse_url(3) instead.
• OCSP_REQ_CTX type and OCSP_REQ_CTX_*() functions
These methods were used to collect all necessary data to form a HTTP
request, and to perform the HTTP transfer with that request. With
OpenSSL 3.0, the type is OSSL_HTTP_REQ_CTX, and the deprecated
functions are replaced with OSSL_HTTP_REQ_CTX_*(). See
OSSL_HTTP_REQ_CTX(3) for additional details.
• OPENSSL_fork_child(), OPENSSL_fork_parent(), OPENSSL_fork_prepare()
There is no replacement for these functions. These pthread fork
support methods were unused by OpenSSL.
• OSSL_STORE_ctrl(), OSSL_STORE_do_all_loaders(),
OSSL_STORE_LOADER_get0_engine(), OSSL_STORE_LOADER_get0_scheme(),
OSSL_STORE_LOADER_new(), OSSL_STORE_LOADER_set_attach(),
OSSL_STORE_LOADER_set_close(), OSSL_STORE_LOADER_set_ctrl(),
OSSL_STORE_LOADER_set_eof(), OSSL_STORE_LOADER_set_error(),
OSSL_STORE_LOADER_set_expect(), OSSL_STORE_LOADER_set_find(),
OSSL_STORE_LOADER_set_load(), OSSL_STORE_LOADER_set_open(),
OSSL_STORE_LOADER_set_open_ex(), OSSL_STORE_register_loader(),
OSSL_STORE_unregister_loader(), OSSL_STORE_vctrl()
These functions helped applications and engines create loaders for
schemes they supported. These are all deprecated and discouraged in
favour of provider implementations, see provider-storemgmt(7).
• PEM_read_DHparams(), PEM_read_bio_DHparams(), PEM_read_DSAparams(),
PEM_read_bio_DSAparams(), PEM_read_DSAPrivateKey(),
PEM_read_DSA_PUBKEY(), PEM_read_bio_DSAPrivateKey and
PEM_read_bio_DSA_PUBKEY(), PEM_read_ECPKParameters(),
PEM_read_ECPrivateKey(), PEM_read_EC_PUBKEY(),
PEM_read_bio_ECPKParameters(), PEM_read_bio_ECPrivateKey(),
PEM_read_bio_EC_PUBKEY(), PEM_read_RSAPrivateKey(),
PEM_read_RSA_PUBKEY(), PEM_read_RSAPublicKey(),
PEM_read_bio_RSAPrivateKey(), PEM_read_bio_RSA_PUBKEY(),
PEM_read_bio_RSAPublicKey(), PEM_write_bio_DHparams(),
PEM_write_bio_DHxparams(), PEM_write_DHparams(),
PEM_write_DHxparams(), PEM_write_DSAparams(),
PEM_write_DSAPrivateKey(), PEM_write_DSA_PUBKEY(),
PEM_write_bio_DSAparams(), PEM_write_bio_DSAPrivateKey(),
PEM_write_bio_DSA_PUBKEY(), PEM_write_ECPKParameters(),
PEM_write_ECPrivateKey(), PEM_write_EC_PUBKEY(),
PEM_write_bio_ECPKParameters(), PEM_write_bio_ECPrivateKey(),
PEM_write_bio_EC_PUBKEY(), PEM_write_RSAPrivateKey(),
PEM_write_RSA_PUBKEY(), PEM_write_RSAPublicKey(),
PEM_write_bio_RSAPrivateKey(), PEM_write_bio_RSA_PUBKEY(),
PEM_write_bio_RSAPublicKey(),
See "Deprecated low-level key reading and writing functions"
• PKCS1_MGF1()
See "Deprecated low-level encryption functions".
• RAND_get_rand_method(), RAND_set_rand_method(), RAND_OpenSSL(),
RAND_set_rand_engine()
Applications should instead use RAND_set_DRBG_type(3), EVP_RAND(3)
and EVP_RAND(7). See RAND_set_rand_method(3) for more details.
• RC2_encrypt(), RC2_decrypt(), RC2_set_key(), RC2_cbc_encrypt(),
RC2_cfb64_encrypt(), RC2_ecb_encrypt(), RC2_ofb64_encrypt(), RC4(),
RC4_set_key(), RC4_options(), RC5_32_encrypt(), RC5_32_set_key(),
RC5_32_decrypt(), RC5_32_cbc_encrypt(), RC5_32_cfb64_encrypt(),
RC5_32_ecb_encrypt(), RC5_32_ofb64_encrypt()
See "Deprecated low-level encryption functions". The Algorithms
"RC2", "RC4" and "RC5" have been moved to the Legacy Provider.
• RIPEMD160(), RIPEMD160_Init(), RIPEMD160_Update(),
RIPEMD160_Final(), RIPEMD160_Transform()
See "Deprecated low-level digest functions". The RIPE algorithm has
been moved to the Legacy Provider.
• RSA_bits(), RSA_security_bits(), RSA_size()
Use EVP_PKEY_get_bits(3), EVP_PKEY_get_security_bits(3) and
EVP_PKEY_get_size(3).
• RSA_check_key(), RSA_check_key_ex()
See "Deprecated low-level validation functions"
• RSA_clear_flags(), RSA_flags(), RSA_set_flags(), RSA_test_flags(),
RSA_setup_blinding(), RSA_blinding_off(), RSA_blinding_on()
All of these RSA flags have been deprecated without replacement:
RSA_FLAG_BLINDING, RSA_FLAG_CACHE_PRIVATE, RSA_FLAG_CACHE_PUBLIC,
RSA_FLAG_EXT_PKEY, RSA_FLAG_NO_BLINDING, RSA_FLAG_THREAD_SAFE
RSA_METHOD_FLAG_NO_CHECK
• RSA_generate_key_ex(), RSA_generate_multi_prime_key()
See "Deprecated low-level key generation functions".
• RSA_get0_engine()
See "Providers are a replacement for engines and low-level method
overrides"
• RSA_get0_crt_params(), RSA_get0_d(), RSA_get0_dmp1(),
RSA_get0_dmq1(), RSA_get0_e(), RSA_get0_factors(), RSA_get0_iqmp(),
RSA_get0_key(), RSA_get0_multi_prime_crt_params(),
RSA_get0_multi_prime_factors(), RSA_get0_n(), RSA_get0_p(),
RSA_get0_pss_params(), RSA_get0_q(),
RSA_get_multi_prime_extra_count()
See "Deprecated low-level key parameter getters"
• RSA_new(), RSA_free(), RSA_up_ref()
See "Deprecated low-level object creation".
• RSA_get_default_method(), RSA_get_ex_data and RSA_get_method()
See "Providers are a replacement for engines and low-level method
overrides".
• RSA_get_version()
There is no replacement.
• RSA_meth_*(), RSA_new_method(), RSA_null_method and
RSA_PKCS1_OpenSSL()
See "Providers are a replacement for engines and low-level method
overrides".
• RSA_padding_add_*(), RSA_padding_check_*()
See "Deprecated low-level signing functions" and "Deprecated low-
level encryption functions".
• RSA_print(), RSA_print_fp()
See "Deprecated low-level key printing functions"
• RSA_public_encrypt(), RSA_private_decrypt()
See "Deprecated low-level encryption functions"
• RSA_private_encrypt(), RSA_public_decrypt()
This is equivalent to doing sign and verify recover operations (with
a padding mode of none). See "Deprecated low-level signing
functions".
• RSAPrivateKey_dup(), RSAPublicKey_dup()
There is no direct replacement. Applications may use
EVP_PKEY_dup(3).
• RSAPublicKey_it(), RSAPrivateKey_it()
See "Deprecated low-level key reading and writing functions"
• RSA_set0_crt_params(), RSA_set0_factors(), RSA_set0_key(),
RSA_set0_multi_prime_params()
See "Deprecated low-level key parameter setters".
• RSA_set_default_method(), RSA_set_method(), RSA_set_ex_data()
See "Providers are a replacement for engines and low-level method
overrides"
• RSA_sign(), RSA_sign_ASN1_OCTET_STRING(), RSA_verify(),
RSA_verify_ASN1_OCTET_STRING(), RSA_verify_PKCS1_PSS(),
RSA_verify_PKCS1_PSS_mgf1()
See "Deprecated low-level signing functions".
• RSA_X931_derive_ex(), RSA_X931_generate_key_ex(), RSA_X931_hash_id()
There are no replacements for these functions. X931 padding can be
set using "Signature Parameters" in EVP_SIGNATURE-RSA(7). See
OSSL_SIGNATURE_PARAM_PAD_MODE.
• SEED_encrypt(), SEED_decrypt(), SEED_set_key(), SEED_cbc_encrypt(),
SEED_cfb128_encrypt(), SEED_ecb_encrypt(), SEED_ofb128_encrypt()
See "Deprecated low-level encryption functions". The SEED algorithm
has been moved to the Legacy Provider.
• SHA1_Init(), SHA1_Update(), SHA1_Final(), SHA1_Transform(),
SHA224_Init(), SHA224_Update(), SHA224_Final(), SHA256_Init(),
SHA256_Update(), SHA256_Final(), SHA256_Transform(), SHA384_Init(),
SHA384_Update(), SHA384_Final(), SHA512_Init(), SHA512_Update(),
SHA512_Final(), SHA512_Transform()
See "Deprecated low-level digest functions".
• SRP_Calc_A(), SRP_Calc_B(), SRP_Calc_client_key(),
SRP_Calc_server_key(), SRP_Calc_u(), SRP_Calc_x(),
SRP_check_known_gN_param(), SRP_create_verifier(),
SRP_create_verifier_BN(), SRP_get_default_gN(), SRP_user_pwd_free(),
SRP_user_pwd_new(), SRP_user_pwd_set0_sv(), SRP_user_pwd_set1_ids(),
SRP_user_pwd_set_gN(), SRP_VBASE_add0_user(), SRP_VBASE_free(),
SRP_VBASE_get1_by_user(), SRP_VBASE_init(), SRP_VBASE_new(),
SRP_Verify_A_mod_N(), SRP_Verify_B_mod_N()
There are no replacements for the SRP functions.
• SSL_CTX_set_tmp_dh_callback(), SSL_set_tmp_dh_callback(),
SSL_CTX_set_tmp_dh(), SSL_set_tmp_dh()
These are used to set the Diffie-Hellman (DH) parameters that are to
be used by servers requiring ephemeral DH keys. Instead applications
should consider using the built-in DH parameters that are available
by calling SSL_CTX_set_dh_auto(3) or SSL_set_dh_auto(3). If custom
parameters are necessary then applications can use the alternative
functions SSL_CTX_set0_tmp_dh_pkey(3) and SSL_set0_tmp_dh_pkey(3).
There is no direct replacement for the "callback" functions. The
callback was originally useful in order to have different parameters
for export and non-export ciphersuites. Export ciphersuites are no
longer supported by OpenSSL. Use of the callback functions should be
replaced by one of the other methods described above.
• SSL_CTX_set_tlsext_ticket_key_cb()
Use the new SSL_CTX_set_tlsext_ticket_key_evp_cb(3) function
instead.
• WHIRLPOOL(), WHIRLPOOL_Init(), WHIRLPOOL_Update(),
WHIRLPOOL_Final(), WHIRLPOOL_BitUpdate()
See "Deprecated low-level digest functions". The Whirlpool
algorithm has been moved to the Legacy Provider.
• X509_certificate_type()
This was an undocumented function. Applications can use
X509_get0_pubkey(3) and X509_get0_signature(3) instead.
• X509_http_nbio(), X509_CRL_http_nbio()
Use X509_load_http(3) and X509_CRL_load_http(3) instead.
NID handling for provided keys and algorithms
The following functions for NID (numeric id) handling have changed
semantics.
• EVP_PKEY_id(), EVP_PKEY_get_id()
This function was previously used to reliably return the NID of an
EVP_PKEY object, e.g., to look up the name of the algorithm of such
EVP_PKEY by calling OBJ_nid2sn(3). With the introduction of
provider(7)s EVP_PKEY_id() or its new equivalent EVP_PKEY_get_id(3)
might now also return the value -1 (EVP_PKEY_KEYMGMT) indicating the
use of a provider to implement the EVP_PKEY object. Therefore, the
use of EVP_PKEY_get0_type_name(3) is recommended for retrieving the
name of the EVP_PKEY algorithm.
Using the FIPS Module in applications
See fips_module(7) and OSSL_PROVIDER-FIPS(7) for details.
OpenSSL command line application changes
New applications
openssl kdf uses the new EVP_KDF(3) API. openssl kdf uses the new
EVP_MAC(3) API.
Added options
-provider_path and -provider are available to all apps and can be used
multiple times to load any providers, such as the 'legacy' provider or
third party providers. If used then the 'default' provider would also
need to be specified if required. The -provider_path must be specified
before the -provider option.
The list app has many new options. See openssl-list(1) for more
information.
-crl_lastupdate and -crl_nextupdate used by openssl ca allows explicit
setting of fields in the generated CRL.
Removed options
Interactive mode is not longer available.
The -crypt option used by openssl passwd. The -c option used by openssl
x509, openssl dhparam, openssl dsaparam, and openssl ecparam.
Other Changes
The output of Command line applications may have minor changes. These
are primarily changes in capitalisation and white space. However, in
some cases, there are additional differences. For example, the DH
parameters output from openssl dhparam now lists 'P', 'Q', 'G' and
'pcounter' instead of 'prime', 'generator', 'subgroup order' and
'counter' respectively.
The openssl commands that read keys, certificates, and CRLs now
automatically detect the PEM or DER format of the input files so it is
not necessary to explicitly specify the input format anymore. However if
the input format option is used the specified format will be required.
openssl speed no longer uses low-level API calls. This implies some of
the performance numbers might not be comparable with the previous
releases due to higher overhead. This applies particularly to measuring
performance on smaller data chunks.
b<openssl dhparam>, openssl dsa, openssl gendsa, openssl dsaparam,
openssl genrsa and openssl rsa have been modified to use PKEY APIs.
openssl genrsa and openssl rsa now write PKCS #8 keys by default.
Default settings
"SHA256" is now the default digest for TS query used by openssl ts.
Deprecated apps
openssl rsautl is deprecated, use openssl pkeyutl instead. openssl
dhparam, openssl dsa, openssl gendsa, openssl dsaparam, openssl genrsa,
openssl rsa, openssl genrsa and openssl rsa are now in maintenance mode
and no new features will be added to them.
TLS Changes
• TLS 1.3 FFDHE key exchange support added
This uses DH safe prime named groups.
• Support for fully "pluggable" TLSv1.3 groups.
This means that providers may supply their own group implementations
(using either the "key exchange" or the "key encapsulation" methods)
which will automatically be detected and used by libssl.
• SSL and SSL_CTX options are now 64 bit instead of 32 bit.
The signatures of the functions to get and set options on SSL and
SSL_CTX objects changed from "unsigned long" to "uint64_t" type.
This may require source code changes. For example it is no longer
possible to use the SSL_OP_ macro values in preprocessor "#if"
conditions. However it is still possible to test whether these
macros are defined or not.
See SSL_CTX_get_options(3), SSL_CTX_set_options(3),
SSL_get_options(3) and SSL_set_options(3).
• SSL_set1_host() and SSL_add1_host() Changes
These functions now take IP literal addresses as well as actual
hostnames.
• Added SSL option SSL_OP_CLEANSE_PLAINTEXT
If the option is set, openssl cleanses (zeroizes) plaintext bytes
from internal buffers after delivering them to the application.
Note, the application is still responsible for cleansing other
copies (e.g.: data received by SSL_read(3)).
• Client-initiated renegotiation is disabled by default.
To allow it, use the -client_renegotiation option, the
SSL_OP_ALLOW_CLIENT_RENEGOTIATION flag, or the "ClientRenegotiation"
config parameter as appropriate.
• Secure renegotiation is now required by default for TLS connections
Support for RFC 5746 secure renegotiation is now required by default
for SSL or TLS connections to succeed. Applications that require
the ability to connect to legacy peers will need to explicitly set
SSL_OP_LEGACY_SERVER_CONNECT. Accordingly,
SSL_OP_LEGACY_SERVER_CONNECT is no longer set as part of SSL_OP_ALL.
• Combining the Configure options no-ec and no-dh no longer disables
TLSv1.3
Typically if OpenSSL has no EC or DH algorithms then it cannot
support connections with TLSv1.3. However OpenSSL now supports
"pluggable" groups through providers. Therefore third party
providers may supply group implementations even where there are no
built-in ones. Attempting to create TLS connections in such a build
without also disabling TLSv1.3 at run time or using third party
provider groups may result in handshake failures. TLSv1.3 can be
disabled at compile time using the "no-tls1_3" Configure option.
• SSL_CTX_set_ciphersuites() and SSL_set_ciphersuites() changes.
The methods now ignore unknown ciphers.
• Security callback change.
The security callback, which can be customised by application code,
supports the security operation SSL_SECOP_TMP_DH. This is defined to
take an EVP_PKEY in the "other" parameter. In most places this is
what is passed. All these places occur server side. However there
was one client side call of this security operation and it passed a
DH object instead. This is incorrect according to the definition of
SSL_SECOP_TMP_DH, and is inconsistent with all of the other
locations. Therefore this client side call has been changed to pass
an EVP_PKEY instead.
• New SSL option SSL_OP_IGNORE_UNEXPECTED_EOF
The SSL option SSL_OP_IGNORE_UNEXPECTED_EOF is introduced. If that
option is set, an unexpected EOF is ignored, it pretends a close
notify was received instead and so the returned error becomes
SSL_ERROR_ZERO_RETURN.
• The security strength of SHA1 and MD5 based signatures in TLS has
been reduced.
This results in SSL 3, TLS 1.0, TLS 1.1 and DTLS 1.0 no longer
working at the default security level of 1 and instead requires
security level 0. The security level can be changed either using the
cipher string with @SECLEVEL, or calling
SSL_CTX_set_security_level(3). This also means that where the
signature algorithms extension is missing from a ClientHello then
the handshake will fail in TLS 1.2 at security level 1. This is
because, although this extension is optional, failing to provide one
means that OpenSSL will fallback to a default set of signature
algorithms. This default set requires the availability of SHA1.
• X509 certificates signed using SHA1 are no longer allowed at
security level 1 and above.
In TLS/SSL the default security level is 1. It can be set either
using the cipher string with @SECLEVEL, or calling
SSL_CTX_set_security_level(3). If the leaf certificate is signed
with SHA-1, a call to SSL_CTX_use_certificate(3) will fail if the
security level is not lowered first. Outside TLS/SSL, the default
security level is -1 (effectively 0). It can be set using
X509_VERIFY_PARAM_set_auth_level(3) or using the -auth_level options
of the commands.
SEE ALSO
fips_module(7)
HISTORY
The migration guide was created for OpenSSL 3.0.
COPYRIGHT
Copyright 2021-2025 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
3.5.4 2025-09-30 OSSL-GUIDE-MIGRATION(7SSL)
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