Provided by: openssl_1.0.1f-1ubuntu2.27_amd64 
NAME
cms - CMS utility
SYNOPSIS
openssl cms [-encrypt] [-decrypt] [-sign] [-verify] [-cmsout] [-resign] [-data_create]
[-data_out] [-digest_create] [-digest_verify] [-compress] [-uncompress]
[-EncryptedData_encrypt] [-sign_receipt] [-verify_receipt receipt] [-in filename] [-inform
SMIME|PEM|DER] [-rctform SMIME|PEM|DER] [-out filename] [-outform SMIME|PEM|DER] [-stream
-indef -noindef] [-noindef] [-content filename] [-text] [-noout] [-print] [-CAfile file]
[-CApath dir] [-no_alt_chains] [-md digest] [-[cipher]] [-nointern]
[-no_signer_cert_verify] [-nocerts] [-noattr] [-nosmimecap] [-binary] [-nodetach]
[-certfile file] [-certsout file] [-signer file] [-recip file] [-keyid]
[-receipt_request_all -receipt_request_first] [-receipt_request_from emailaddress]
[-receipt_request_to emailaddress] [-receipt_request_print] [-secretkey key] [-secretkeyid
id] [-econtent_type type] [-inkey file] [-passin arg] [-rand file(s)] [cert.pem...] [-to
addr] [-from addr] [-subject subj] [cert.pem]...
DESCRIPTION
The cms command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and verify,
compress and uncompress S/MIME messages.
COMMAND OPTIONS
There are fourteen operation options that set the type of operation to be performed. The
meaning of the other options varies according to the operation type.
-encrypt
encrypt mail for the given recipient certificates. Input file is the message to be
encrypted. The output file is the encrypted mail in MIME format. The actual CMS type
is <B>EnvelopedData<B>.
-decrypt
decrypt mail using the supplied certificate and private key. Expects an encrypted mail
message in MIME format for the input file. The decrypted mail is written to the output
file.
-sign
sign mail using the supplied certificate and private key. Input file is the message to
be signed. The signed message in MIME format is written to the output file.
-verify
verify signed mail. Expects a signed mail message on input and outputs the signed
data. Both clear text and opaque signing is supported.
-cmsout
takes an input message and writes out a PEM encoded CMS structure.
-resign
resign a message: take an existing message and one or more new signers.
-data_create
Create a CMS Data type.
-data_out
Data type and output the content.
-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 suppled content using supplied symmetric key and algorithm using a CMS
EncrytedData type and output the content.
-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.
-in filename
the input message to be encrypted or signed or the message to be decrypted or
verified.
-inform SMIME|PEM|DER
this specifies the input format for the CMS structure. The default is SMIME which
reads an S/MIME format message. PEM and DER format change this to expect PEM and DER
format CMS structures instead. This currently only affects the input format of the CMS
structure, if no CMS structure is being input (for example with -encrypt or -sign)
this option has no effect.
-rctform SMIME|PEM|DER
specify the format for a signed receipt for use with the -receipt_verify operation.
-out filename
the message text that has been decrypted or verified or the output MIME format message
that has been signed or verified.
-outform SMIME|PEM|DER
this specifies the output format for the CMS structure. The default is SMIME which
writes an S/MIME format message. PEM and DER format change this to write PEM and DER
format CMS structures instead. This currently only affects the output format of the
CMS structure, if no CMS structure is being output (for example with -verify or
-decrypt) this option has no effect.
-stream -indef -noindef
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.
-content filename
This specifies a file containing the detached content, this is only useful with 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.
-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.
-noout
for the -cmsout operation do not output the parsed CMS structure. This is useful when
combined with the -print option or if the syntax of the CMS structure is being
checked.
-print
for the -cmsout operation print out all fields of the CMS structure. This is mainly
useful for testing purposes.
-CAfile file
a file containing trusted CA certificates, only used with -verify.
-CApath dir
a directory containing trusted CA certificates, only used with -verify. This directory
must be a standard certificate directory: that is a hash of each subject name (using
x509 -hash) should be linked to each certificate.
-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).
-[cipher]
the encryption algorithm to use. For example triple DES (168 bits) - -des3 or 256 bit
AES - -aes256. 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 enc for a
list of ciphers supported by your version of OpenSSL.
If not specified triple DES is used. Only used with -encrypt and -EncryptedData_create
commands.
-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.
-no_signer_cert_verify
do not verify the signers certificate of a signed message.
-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
signing time and content type are still included.
-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.
-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.
-certfile file
allows additional certificates to be specified. When signing these will be included
with the message. When verifying these will be searched for the signers certificates.
The certificates should be in PEM format.
-certsout file
any certificates contained in the message are written to file.
-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. If a message is being verified
then the signers certificates will be written to this file if the verification was
successful.
-recip file
the recipients certificate when decrypting a message. This certificate must match one
of the recipients of the message or an error occurs.
-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.
-receipt_request_all -receipt_request_first
for -sign option include a signed receipt request. Indicate requests should be
provided by all receipient 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 it requested.
-receipt_request_print
For the -verify operation print out the contents of any signed receipt requests.
-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
-EncrryptedData_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.
-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.
-inkey file
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 the
PASS PHRASE ARGUMENTS section in openssl(1).
-rand file(s)
a file or files containing random data used to seed the random number generator, or an
EGD socket (see RAND_egd(3)). Multiple files can be specified separated by a OS-
dependent character. The separator is ; for MS-Windows, , for OpenVMS, and : for all
others.
cert.pem...
one or more certificates of message recipients: used when encrypting a message.
-to, -from, -subject
the relevant mail 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.
-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check,
-extended_crl, -x509_strict, -policy -check_ss_sig -no_alt_chains
Set various certificate chain valiadition option. See the verify manual page for
details.
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 wont 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 experimental 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.
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.
The smime utility can only process the older PKCS#7 format. The cms utility 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.
Additionally the -EncryptedData_create and -data_create type cannot be processed by the
older smime 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 mail:
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
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.
HISTORY
The use of multiple -signer options and the -resign command were first added in OpenSSL
1.0.0
The -no_alt_chains options was first added to OpenSSL 1.0.1n and 1.0.2b.