OPENSSL-CMS(1SSL) OpenSSL OPENSSL-CMS(1SSL)
NAME
openssl-cms - CMS command
SYNOPSIS
openssl cms [-help]
General options:
[-in filename] [-out filename] [-config configfile]
Operation options:
[-encrypt] [-decrypt] [-sign] [-verify] [-resign] [-sign_receipt]
[-verify_receipt receipt] [-digest digest] [-digest_create]
[-digest_verify] [-compress] [-uncompress] [-EncryptedData_encrypt]
[-EncryptedData_decrypt] [-data_create] [-data_out] [-cmsout]
File format options:
[-inform DER|PEM|SMIME] [-outform DER|PEM|SMIME] [-rctform
DER|PEM|SMIME] [-stream] [-indef] [-noindef] [-binary] [-crlfeol]
[-asciicrlf]
Keys and password options:
[-pwri_password password] [-secretkey key] [-secretkeyid id] [-inkey
filename|uri] [-passin arg] [-keyopt name:parameter] [-keyform
DER|PEM|P12|ENGINE] [-engine id] [-provider name] [-provider-path path]
[-provparam [name:]key=value] [-propquery propq] [-rand files]
[-writerand file]
Encryption options:
[-originator file] [-recip file] [recipient-cert ...] [-cipher] [-wrap
cipher] [-aes128-wrap] [-aes192-wrap] [-aes256-wrap] [-des3-wrap]
[-debug_decrypt]
Signing options:
[-md digest] [-signer file] [-certfile file] [-cades] [-nodetach]
[-nocerts] [-noattr] [-nosmimecap] [-no_signing_time]
[-receipt_request_all] [-receipt_request_first] [-receipt_request_from
emailaddress] [-receipt_request_to emailaddress]
Verification options:
[-signer file] [-content filename] [-no_content_verify]
[-no_attr_verify] [-nosigs] [-noverify] [-nointern] [-cades]
[-verify_retcode] [-CAfile file] [-no-CAfile] [-CApath dir] [-no-CApath]
[-CAstore uri] [-no-CAstore]
Output options:
[-keyid] [-econtent_type type] [-text] [-certsout file] [-to addr]
[-from addr] [-subject subj]
Printing options:
[-noout] [-print] [-nameopt option] [-receipt_request_print]
Validation options:
[-allow_proxy_certs] [-attime timestamp] [-no_check_time]
[-check_ss_sig] [-crl_check] [-crl_check_all] [-explicit_policy]
[-extended_crl] [-ignore_critical] [-inhibit_any] [-inhibit_map]
[-partial_chain] [-policy arg] [-policy_check] [-policy_print] [-purpose
purpose] [-suiteB_128] [-suiteB_128_only] [-suiteB_192] [-trusted_first]
[-no_alt_chains] [-use_deltas] [-auth_level num] [-verify_depth num]
[-verify_email email] [-verify_hostname hostname] [-verify_ip ip]
[-verify_name name] [-x509_strict] [-issuer_checks]
DESCRIPTION
This command handles data in CMS format such as S/MIME v3.1 email
messages. It can encrypt, decrypt, sign, verify, compress, uncompress,
and print messages.
OPTIONS
There are a number of operation options that set the type of operation
to be performed: encrypt, decrypt, sign, verify, resign, sign_receipt,
verify_receipt, digest_create, digest_verify, compress, uncompress,
EncryptedData_encrypt, EncryptedData_decrypt, data_create, data_out, or
cmsout. The relevance of the other options depends on the operation
type and their meaning may vary according to it.
-help
Print out a usage message.
General options
-in filename
The input message to be encrypted or signed or the message to be
decrypted or verified.
-out filename
The message text that has been decrypted or verified or the output
MIME format message that has been signed or verified.
-config configfile
See "Configuration Option" in openssl(1).
Operation options
-encrypt
Encrypt data for the given recipient certificates. Input file is the
message to be encrypted. The output file is the encrypted data in
MIME format. The actual CMS type is EnvelopedData.
Note that no revocation check is done for the recipient cert, so if
that key has been compromised, others may be able to decrypt the
text.
-decrypt
Decrypt data using the supplied certificate and private key. Expects
encrypted datain MIME format for the input file. The decrypted data
is written to the output file.
-sign
Sign data using the supplied certificate and private key. Input file
is the message to be signed. The signed data in MIME format is
written to the output file.
-verify
Verify signed data. Expects a signed data on input and outputs the
signed data. Both clear text and opaque signing is supported.
By default, validation of signer certificates and their chain is
done w.r.t. the S/MIME signing ("smimesign") purpose. For details
see "Certificate Extensions" in openssl-verification-options(1).
-resign
Resign a message: take an existing message and one or more new
signers.
-sign_receipt
Generate and output a signed receipt for the supplied message. The
input message must contain a signed receipt request. Functionality
is otherwise similar to the -sign operation.
-verify_receipt receipt
Verify a signed receipt in filename receipt. The input message must
contain the original receipt request. Functionality is otherwise
similar to the -verify operation.
-digest digest
When used with -sign, provides the digest in hexadecimal form
instead of computing it from the original message content. Cannot be
combined with -in or -nodetach.
This operation is the CMS equivalent of openssl-pkeyutl(1) signing.
When signing a pre-computed digest, the security relies on the
digest and its computation from the original message being trusted.
-digest_create
Create a CMS DigestedData type.
-digest_verify
Verify a CMS DigestedData type and output the content.
-compress
Create a CMS CompressedData type. OpenSSL must be compiled with zlib
support for this option to work, otherwise it will output an error.
-uncompress
Uncompress a CMS CompressedData type and output the content. OpenSSL
must be compiled with zlib support for this option to work,
otherwise it will output an error.
-EncryptedData_encrypt
Encrypt content using supplied symmetric key and algorithm using a
CMS EncryptedData type and output the content.
-EncryptedData_decrypt
Decrypt content using supplied symmetric key and algorithm using a
CMS EncryptedData type and output the content.
-data_create
Create a CMS Data type.
-data_out
Data type and output the content.
-cmsout
Takes an input message and writes out a PEM encoded CMS structure.
File format options
-inform DER|PEM|SMIME
The input format of the CMS structure (if one is being read); the
default is SMIME. See openssl-format-options(1) for details.
-outform DER|PEM|SMIME
The output format of the CMS structure (if one is being written);
the default is SMIME. See openssl-format-options(1) for details.
-rctform DER|PEM|SMIME
The signed receipt format for use with the -receipt_verify; the
default is SMIME. See openssl-format-options(1) for details.
-stream, -indef
The -stream and -indef options are equivalent and enable streaming
I/O for encoding operations. This permits single pass processing of
data without the need to hold the entire contents in memory,
potentially supporting very large files. Streaming is automatically
set for S/MIME signing with detached data if the output format is
SMIME it is currently off by default for all other operations.
-noindef
Disable streaming I/O where it would produce and indefinite length
constructed encoding. This option currently has no effect. In future
streaming will be enabled by default on all relevant operations and
this option will disable it.
-binary
Normally the input message is converted to "canonical" format which
is effectively using CR and LF as end of line: as required by the
S/MIME specification. When this option is present no translation
occurs. This is useful when handling binary data which may not be in
MIME format.
-crlfeol
Normally the output file uses a single LF as end of line. When this
option is present CRLF is used instead.
-asciicrlf
When signing use ASCII CRLF format canonicalisation. This strips
trailing whitespace from all lines, deletes trailing blank lines at
EOF and sets the encapsulated content type. This option is normally
used with detached content and an output signature format of DER.
This option is not normally needed when verifying as it is enabled
automatically if the encapsulated content format is detected.
Keys and password options
-pwri_password password
Specify password for recipient.
-secretkey key
Specify symmetric key to use. The key must be supplied in hex format
and be consistent with the algorithm used. Supported by the
-EncryptedData_encrypt -EncryptedData_decrypt, -encrypt and -decrypt
options. When used with -encrypt or -decrypt the supplied key is
used to wrap or unwrap the content encryption key using an AES key
in the KEKRecipientInfo type.
-secretkeyid id
The key identifier for the supplied symmetric key for
KEKRecipientInfo type. This option must be present if the
-secretkey option is used with -encrypt. With -decrypt operations
the id is used to locate the relevant key if it is not supplied then
an attempt is used to decrypt any KEKRecipientInfo structures.
-inkey filename|uri
The private key to use when signing or decrypting. This must match
the corresponding certificate. If this option is not specified then
the private key must be included in the certificate file specified
with the -recip or -signer file. When signing this option can be
used multiple times to specify successive keys.
-passin arg
The private key password source. For more information about the
format of arg see openssl-passphrase-options(1).
-keyopt name:parameter
For signing and encryption this option can be used multiple times to
set customised parameters for the preceding key or certificate. It
can currently be used to set RSA-PSS for signing, RSA-OAEP for
encryption or to modify default parameters for ECDH.
-keyform DER|PEM|P12|ENGINE
The format of the private key file; unspecified by default. See
openssl-format-options(1) for details.
-engine id
See "Engine Options" in openssl(1). This option is deprecated.
-provider name
-provider-path path
-provparam [name:]key=value
-propquery propq
See "Provider Options" in openssl(1), provider(7), and property(7).
-rand files, -writerand file
See "Random State Options" in openssl(1) for details.
Encryption and decryption options
-originator file
A certificate of the originator of the encrypted message. Necessary
for decryption when Key Agreement is in use for a shared key.
Currently, not allowed for encryption.
-recip file
When decrypting a message this specifies the certificate of the
recipient. The certificate must match one of the recipients of the
message.
When encrypting a message this option may be used multiple times to
specify each recipient. This form must be used if customised
parameters are required (for example to specify RSA-OAEP).
Only certificates carrying RSA, Diffie-Hellman or EC keys are
supported by this option.
recipient-cert ...
This is an alternative to using the -recip option when encrypting a
message. One or more certificate filenames may be given.
-cipher
The encryption algorithm to use. For example, AES (256 bits) -
-aes256 or triple DES (168 bits) - -des3. Any standard algorithm
name (as used by the EVP_get_cipherbyname() function) can also be
used preceded by a dash, for example -aes-128-cbc. See
openssl-enc(1) for a list of ciphers supported by your version of
OpenSSL.
Currently, the AES variants with GCM mode are the only supported
AEAD algorithms.
If not specified, AES-256-CBC is used as the default. Only used with
-encrypt and -EncryptedData_create commands.
-wrap cipher
Cipher algorithm to use for key wrap when encrypting the message
using Key Agreement for key transport. The algorithm specified
should be suitable for key wrap.
-aes128-wrap, -aes192-wrap, -aes256-wrap, -des3-wrap
Use AES128, AES192, AES256, or 3DES-EDE, respectively, to wrap key.
Depending on the OpenSSL build options used, -des3-wrap may not be
supported.
-debug_decrypt
This option sets the CMS_DEBUG_DECRYPT flag. This option should be
used with caution: see the notes section below.
Signing options
-md digest
Digest algorithm to use when signing or resigning. If not present
then the default digest algorithm for the signing key will be used
(usually SHA1).
-signer file
A signing certificate. When signing or resigning a message, this
option can be used multiple times if more than one signer is
required.
-certfile file
Allows additional certificates to be specified. When signing these
will be included with the message. When verifying, these will be
searched for signer certificates and will be used for chain
building.
The input can be in PEM, DER, or PKCS#12 format.
-cades
When used with -sign, add an ESS signingCertificate or ESS
signingCertificateV2 signed-attribute to the SignerInfo, in order to
make the signature comply with the requirements for a CAdES Basic
Electronic Signature (CAdES-BES).
-nodetach
When signing a message use opaque signing: this form is more
resistant to translation by mail relays but it cannot be read by
mail agents that do not support S/MIME. Without this option
cleartext signing with the MIME type multipart/signed is used.
-nocerts
When signing a message the signer's certificate is normally included
with this option it is excluded. This will reduce the size of the
signed message but the verifier must have a copy of the signers
certificate available locally (passed using the -certfile option for
example).
-noattr
Normally when a message is signed a set of attributes are included
which include the signing time and supported symmetric algorithms.
With this option they are not included.
-nosmimecap
Exclude the list of supported algorithms from signed attributes,
other options such as content type and (optionally) signing time are
still included.
-no_signing_time
Exclude the signing time from signed attributes, other options such
as content type are still included.
-receipt_request_all, -receipt_request_first
For -sign option include a signed receipt request. Indicate requests
should be provided by all recipient or first tier recipients (those
mailed directly and not from a mailing list). Ignored it
-receipt_request_from is included.
-receipt_request_from emailaddress
For -sign option include a signed receipt request. Add an explicit
email address where receipts should be supplied.
-receipt_request_to emailaddress
Add an explicit email address where signed receipts should be sent
to. This option must but supplied if a signed receipt is requested.
Verification options
-signer file
If a message has been verified successfully then the signers
certificate(s) will be written to this file if the verification was
successful.
-content filename
This specifies a file containing the detached content for operations
taking S/MIME input, such as the -verify command. This is only
usable if the CMS structure is using the detached signature form
where the content is not included. This option will override any
content if the input format is S/MIME and it uses the
multipart/signed MIME content type.
-no_content_verify
Do not verify signed content signatures.
-no_attr_verify
Do not verify signed attribute signatures.
-nosigs
Don't verify message signature.
-noverify
Do not verify the signers certificate of a signed message.
-nointern
When verifying a message normally certificates (if any) included in
the message are searched for the signing certificate. With this
option only the certificates specified in the -certfile option are
used. The supplied certificates can still be used as untrusted CAs
however.
-cades
When used with -verify, require and check signer certificate digest.
See the NOTES section for more details.
-verify_retcode
Exit nonzero on verification failure.
-CAfile file, -no-CAfile, -CApath dir, -no-CApath, -CAstore uri,
-no-CAstore
See "Trusted Certificate Options" in openssl-verification-options(1)
for details.
Output options
-keyid
Use subject key identifier to identify certificates instead of
issuer name and serial number. The supplied certificate must include
a subject key identifier extension. Supported by -sign and -encrypt
options.
-econtent_type type
Set the encapsulated content type to type if not supplied the Data
type is used. The type argument can be any valid OID name in either
text or numerical format.
-text
This option adds plain text (text/plain) MIME headers to the
supplied message if encrypting or signing. If decrypting or
verifying it strips off text headers: if the decrypted or verified
message is not of MIME type text/plain then an error occurs.
-certsout file
Any certificates contained in the input message are written to file.
-to, -from, -subject
The relevant email headers. These are included outside the signed
portion of a message so they may be included manually. If signing
then many S/MIME mail clients check the signers certificate's email
address matches that specified in the From: address.
Printing options
-noout
For the -cmsout operation do not output the parsed CMS structure.
This is useful if the syntax of the CMS structure is being checked.
-print
For the -cmsout operation print out all fields of the CMS structure.
This implies -noout. This is mainly useful for testing purposes.
-nameopt option
For the -cmsout operation when -print option is in use, specifies
printing options for string fields. For most cases utf8 is
reasonable value. See openssl-namedisplay-options(1) for details.
-receipt_request_print
For the -verify operation print out the contents of any signed
receipt requests.
Validation options
-allow_proxy_certs, -attime, -no_check_time, -check_ss_sig, -crl_check,
-crl_check_all, -explicit_policy, -extended_crl, -ignore_critical,
-inhibit_any, -inhibit_map, -no_alt_chains, -partial_chain, -policy,
-policy_check, -policy_print, -purpose, -suiteB_128, -suiteB_128_only,
-suiteB_192, -trusted_first, -use_deltas, -auth_level, -verify_depth,
-verify_email, -verify_hostname, -verify_ip, -verify_name, -x509_strict
-issuer_checks
Set various options of certificate chain verification. See
"Verification Options" in openssl-verification-options(1) for
details.
Any validation errors cause the command to exit.
NOTES
The MIME message must be sent without any blank lines between the
headers and the output. Some mail programs will automatically add a
blank line. Piping the mail directly to sendmail is one way to achieve
the correct format.
The supplied message to be signed or encrypted must include the
necessary MIME headers or many S/MIME clients won't display it properly
(if at all). You can use the -text option to automatically add plain
text headers.
A "signed and encrypted" message is one where a signed message is then
encrypted. This can be produced by encrypting an already signed message:
see the examples section.
This version of the program only allows one signer per message but it
will verify multiple signers on received messages. Some S/MIME clients
choke if a message contains multiple signers. It is possible to sign
messages "in parallel" by signing an already signed message.
The options -encrypt and -decrypt reflect common usage in S/MIME
clients. Strictly speaking these process CMS enveloped data: CMS
encrypted data is used for other purposes.
The -resign option uses an existing message digest when adding a new
signer. This means that attributes must be present in at least one
existing signer using the same message digest or this operation will
fail.
The -stream and -indef options enable streaming I/O support. As a
result the encoding is BER using indefinite length constructed encoding
and no longer DER. Streaming is supported for the -encrypt operation and
the -sign operation if the content is not detached.
Streaming is always used for the -sign operation with detached data but
since the content is no longer part of the CMS structure the encoding
remains DER.
If the -decrypt option is used without a recipient certificate then an
attempt is made to locate the recipient by trying each potential
recipient in turn using the supplied private key. To thwart the MMA
attack (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all
recipients are tried whether they succeed or not and if no recipients
match the message is "decrypted" using a random key which will typically
output garbage. The -debug_decrypt option can be used to disable the
MMA attack protection and return an error if no recipient can be found:
this option should be used with caution. For a fuller description see
CMS_decrypt(3)).
CADES BASIC ELECTRONIC SIGNATURE (CADES-BES)
A CAdES Basic Electronic Signature (CAdES-BES), as defined in the
European Standard ETSI EN 319 122-1 V1.1.1, contains:
• The signed user data as defined in CMS (RFC 3852);
• Content-type of the EncapsulatedContentInfo value being signed;
• Message-digest of the eContent OCTET STRING within encapContentInfo
being signed;
• An ESS signingCertificate or ESS signingCertificateV2 attribute, as
defined in Enhanced Security Services (ESS), RFC 2634 and RFC 5035.
An ESS signingCertificate attribute only allows for SHA-1 as digest
algorithm. An ESS signingCertificateV2 attribute allows for any
digest algorithm.
• The digital signature value computed on the user data and, when
present, on the signed attributes.
NOTE that the -cades option applies to the -sign or -verify
operations. With this option, the -verify operation also requires
that the signingCertificate attribute is present and checks that the
given identifiers match the verification trust chain built during
the verification process.
EXIT CODES
0 The operation was completely successfully.
1 An error occurred parsing the command options.
2 One of the input files could not be read.
3 An error occurred creating the CMS file or when reading the MIME
message.
4 An error occurred decrypting or verifying the message.
5 The message was verified correctly but an error occurred writing out
the signers certificates.
COMPATIBILITY WITH PKCS#7 FORMAT
openssl-smime(1) can only process the older PKCS#7 format. openssl cms
supports Cryptographic Message Syntax format. Use of some features will
result in messages which cannot be processed by applications which only
support the older format. These are detailed below.
The use of the -keyid option with -sign or -encrypt.
The -outform PEM option uses different headers.
The -compress option.
The -secretkey option when used with -encrypt.
The use of PSS with -sign.
The use of OAEP or non-RSA keys with -encrypt.
Additionally the -EncryptedData_create and -data_create type cannot be
processed by the older openssl-smime(1) command.
EXAMPLES
Create a cleartext signed message:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem
Create an opaque signed message
openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
-signer mycert.pem
Create a signed message, include some additional certificates and read
the private key from another file:
openssl cms -sign -in in.txt -text -out mail.msg \
-signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
Create a signed message with two signers, use key identifier:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -signer othercert.pem -keyid
Send a signed message under Unix directly to sendmail, including
headers:
openssl cms -sign -in in.txt -text -signer mycert.pem \
-from steve@openssl.org -to someone@somewhere \
-subject "Signed message" | sendmail someone@somewhere
Verify a message and extract the signer's certificate if successful:
openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
Send encrypted mail using triple DES:
openssl cms -encrypt -in in.txt -from steve@openssl.org \
-to someone@somewhere -subject "Encrypted message" \
-des3 user.pem -out mail.msg
Sign and encrypt mail:
openssl cms -sign -in ml.txt -signer my.pem -text \
| openssl cms -encrypt -out mail.msg \
-from steve@openssl.org -to someone@somewhere \
-subject "Signed and Encrypted message" -des3 user.pem
Note: the encryption command does not include the -text option because
the message being encrypted already has MIME headers.
Decrypt a message:
openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
The output from Netscape form signing is a PKCS#7 structure with the
detached signature format. You can use this program to verify the
signature by line wrapping the base64 encoded structure and surrounding
it with:
-----BEGIN PKCS7-----
-----END PKCS7-----
and using the command,
openssl cms -verify -inform PEM -in signature.pem -content content.txt
alternatively you can base64 decode the signature and use
openssl cms -verify -inform DER -in signature.der -content content.txt
Create an encrypted message using 128 bit Camellia:
openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
Add a signer to an existing message:
openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
Sign a message using RSA-PSS:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -keyopt rsa_padding_mode:pss
Create an encrypted message using RSA-OAEP:
openssl cms -encrypt -in plain.txt -out mail.msg \
-recip cert.pem -keyopt rsa_padding_mode:oaep
Use SHA256 KDF with an ECDH certificate:
openssl cms -encrypt -in plain.txt -out mail.msg \
-recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
Print CMS signed binary data in human-readable form:
openssl cms -in signed.cms -binary -inform DER -cmsout -print
BUGS
The MIME parser isn't very clever: it seems to handle most messages that
I've thrown at it but it may choke on others.
The code currently will only write out the signer's certificate to a
file: if the signer has a separate encryption certificate this must be
manually extracted. There should be some heuristic that determines the
correct encryption certificate.
Ideally a database should be maintained of a certificates for each email
address.
The code doesn't currently take note of the permitted symmetric
encryption algorithms as supplied in the SMIMECapabilities signed
attribute. this means the user has to manually include the correct
encryption algorithm. It should store the list of permitted ciphers in a
database and only use those.
No revocation checking is done on the signer's certificate.
SEE ALSO
ossl_store-file(7)
HISTORY
The default encryption cipher was changed from 3DES to AES-256 in
OpenSSL 3.5.
The use of multiple -signer options and the -resign command were first
added in OpenSSL 1.0.0.
The -keyopt option was added in OpenSSL 1.0.2.
Support for RSA-OAEP and RSA-PSS was added in OpenSSL 1.0.2.
The use of non-RSA keys with -encrypt and -decrypt was added in OpenSSL
1.0.2.
The -no_alt_chains option was added in OpenSSL 1.0.2b.
The -nameopt option was added in OpenSSL 3.0.0.
The -engine option was deprecated in OpenSSL 3.0.
The -digest option was added in OpenSSL 3.2.
COPYRIGHT
Copyright 2008-2025 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 OPENSSL-CMS(1SSL)
Generated by dwww version 1.16 on Tue Dec 16 04:07:33 CET 2025.