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Diffstat (limited to 'doc')
-rw-r--r-- | doc/crypto/PKCS7_sign_add_signer.pod | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/doc/crypto/PKCS7_sign_add_signer.pod b/doc/crypto/PKCS7_sign_add_signer.pod new file mode 100644 index 0000000000..2a864e116d --- /dev/null +++ b/doc/crypto/PKCS7_sign_add_signer.pod @@ -0,0 +1,87 @@ +=pod + +=head1 NAME + +PKCS7_sign_add_signer - add a signer PKCS7 signed data structure. + +=head1 SYNOPSIS + + #include <openssl/pkcs7.h> + + PKCS7_SIGNER_INFO *PKCS7_sign_add_signer(PKCS7 *p7, X509 *signcert, EVP_PKEY *pkey, const EVP_MD *md, int flags); + + +=head1 DESCRIPTION + +PKCS7_sign_add_signer() adds a signer with certificate B<signcert> and private +key B<pkey> using message digest B<md> to a PKCS7 signed data structure +B<p7>. + +The PKCS7 structure should be obtained from an initial call to PKCS7_sign() +with the flag B<PKCS7_PARTIAL> set or in the case or re-signing a valid PKCS7 +signed data structure. + +If the B<md> parameter is B<NULL> then the default digest for the public +key algorithm will be used. + +Unless the B<PKCS7_REUSE_DIGEST> flag is set the returned PKCS7 structure +is not complete and must be finalized either by streaming (if applicable) or +a call to PKCS7_final(). + + +=head1 NOTES + +The main purpose of this function is to provide finer control over a PKCS#7 +signed data structure where the simpler PKCS7_sign() function defaults are +not appropriate. For example if multiple signers or non default digest +algorithms are needed. + +Any of the following flags (ored together) can be passed in the B<flags> +parameter. + +If B<PKCS7_REUSE_DIGEST> is set then an attempt is made to copy the content +digest value from the PKCS7 struture: to add a signer to an existing structure. +An error occurs if a matching digest value cannot be found to copy. The +returned PKCS7 structure will be valid and finalized when this flag is set. + +If B<PKCS7_PARTIAL> is set in addition to B<PKCS7_REUSE_DIGEST> then the +B<PKCS7_SIGNER_INO> structure will not be finalized so additional attributes +can be added. In this case an explicit call to PKCS7_SIGNER_INFO_sign() is +needed to finalize it. + +If B<PKCS7_NOCERTS> is set the signer's certificate will not be included in the +PKCS7 structure, the signer's certificate must still be supplied in the +B<signcert> parameter though. This can reduce the size of the signature if the +signers certificate can be obtained by other means: for example a previously +signed message. + +The signedData structure includes several PKCS#7 autenticatedAttributes +including the signing time, the PKCS#7 content type and the supported list of +ciphers in an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no +authenticatedAttributes will be used. If B<PKCS7_NOSMIMECAP> is set then just +the SMIMECapabilities are omitted. + +If present the SMIMECapabilities attribute indicates support for the following +algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of +these algorithms is disabled then it will not be included. + + +PKCS7_sign_add_signers() returns an internal pointer to the PKCS7_SIGNER_INFO +structure just added, this can be used to set additional attributes +before it is finalized. + +=head1 RETURN VALUES + +PKCS7_sign_add_signers() returns an internal pointer to the PKCS7_SIGNER_INFO +structure just added or NULL if an error occurs. + +=head1 SEE ALSO + +L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_sign(3)|PKCS7_sign(3)>, +L<PKCS7_final(3)|PKCS7_final(3)>, + +=head1 HISTORY + +PEM_sign_add_signer() was added to OpenSSL 0.9.9 + +=cut |