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_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] [-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] [-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.

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 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.

COPYRIGHT¶

Copyright 2008-2023 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>.