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PKCS7_SIGN_ADD_SIGNER(3ossl) OpenSSL PKCS7_SIGN_ADD_SIGNER(3ossl)
NAME
PKCS7_sign_add_signer, PKCS7_add_certificate, PKCS7_add_crl - add
information to PKCS7 structure
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);
int PKCS7_add_certificate(PKCS7 *p7, X509 *cert);
int PKCS7_add_crl(PKCS7 *p7, X509_CRL *crl);
DESCRIPTION
PKCS7_sign_add_signer() adds a signer with certificate signcert and
private key pkey using message digest md to a PKCS7 signed data
structure p7.
The PKCS7 structure should be obtained from an initial call to
PKCS7_sign() with the flag PKCS7_PARTIAL set or in the case or re-
signing a valid PKCS#7 signed data structure.
If the md parameter is NULL then the default digest for the public key
algorithm will be used.
Unless the 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().
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 flags
parameter.
If PKCS7_REUSE_DIGEST is set then an attempt is made to copy the
content digest value from the PKCS7 structure: 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 PKCS7_PARTIAL is set in addition to PKCS7_REUSE_DIGEST then the
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 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 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
authenticatedAttributes including the signing time, the PKCS#7 content
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, which can be used to set
additional attributes before it is finalized.
PKCS7_add_certificate() adds to the PKCS7 structure p7 the certificate
cert, which may be an end-entity (signer) certificate or a CA
certificate useful for chain building. This is done internally by
PKCS7_sign_ex(3) and similar signing functions. It may have to be used
before calling PKCS7_verify(3) in order to provide any missing
certificate(s) needed for verification.
PKCS7_add_crl() adds the CRL crl to the PKCS7 structure p7. This may
be called to provide certificate status information to be included when
signing or to use when verifying the PKCS7 structure.
RETURN VALUES
PKCS7_sign_add_signers() returns an internal pointer to the
PKCS7_SIGNER_INFO structure just added or NULL if an error occurs.
PKCS7_add_certificate() and PKCS7_add_crl() return 1 on success, 0 on
error.
SEE ALSO
ERR_get_error(3), PKCS7_sign_ex(3), PKCS7_final(3), PKCS7_verify(3)
HISTORY
The PPKCS7_sign_add_signer() function was added in OpenSSL 1.0.0.
COPYRIGHT
Copyright 2007-2022 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>.
3.0.11 2023-09-19 PKCS7_SIGN_ADD_SIGNER(3ossl)