1PKCS7_SIGN_ADD_SIGNER(3) OpenSSL PKCS7_SIGN_ADD_SIGNER(3)
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6 PKCS7_sign_add_signer - add a signer PKCS7 signed data structure
7
9 #include <openssl/pkcs7.h>
10 PKCS7_SIGNER_INFO *PKCS7_sign_add_signer(PKCS7 *p7, X509 *signcert,
12 EVP_PKEY *pkey, const EVP_MD *md, int flags);
13
15 PKCS7_sign_add_signer() adds a signer with certificate signcert and
16 private key pkey using message digest md to a PKCS7 signed data
17 structure p7.
18 The PKCS7 structure should be obtained from an initial call to
20 PKCS7_sign() with the flag PKCS7_PARTIAL set or in the case or re-
21 signing a valid PKCS7 signed data structure.
22 If the md parameter is NULL then the default digest for the public key
24 algorithm will be used.
25 Unless the PKCS7_REUSE_DIGEST flag is set the returned PKCS7 structure
27 is not complete and must be finalized either by streaming (if
28 applicable) or a call to PKCS7_final().
29
31 The main purpose of this function is to provide finer control over a
32 PKCS#7 signed data structure where the simpler PKCS7_sign() function
33 defaults are not appropriate. For example if multiple signers or non
34 default digest algorithms are needed.
35 Any of the following flags (ored together) can be passed in the flags
37 parameter.
38 If PKCS7_REUSE_DIGEST is set then an attempt is made to copy the
40 content digest value from the PKCS7 structure: to add a signer to an
41 existing structure. An error occurs if a matching digest value cannot
42 be found to copy. The returned PKCS7 structure will be valid and
43 finalized when this flag is set.
44 If PKCS7_PARTIAL is set in addition to PKCS7_REUSE_DIGEST then the
46 PKCS7_SIGNER_INO structure will not be finalized so additional
47 attributes can be added. In this case an explicit call to
48 PKCS7_SIGNER_INFO_sign() is needed to finalize it.
49 If PKCS7_NOCERTS is set the signer's certificate will not be included
51 in the PKCS7 structure, the signer's certificate must still be supplied
52 in the signcert parameter though. This can reduce the size of the
53 signature if the signers certificate can be obtained by other means:
54 for example a previously signed message.
55 The signedData structure includes several PKCS#7
57 authenticatedAttributes including the signing time, the PKCS#7 content
58 type and the supported list of ciphers in an SMIMECapabilities
59 attribute. If PKCS7_NOATTR is set then no authenticatedAttributes will
60 be used. If PKCS7_NOSMIMECAP is set then just the SMIMECapabilities are
61 omitted.
62 If present the SMIMECapabilities attribute indicates support for the
64 following algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40
65 bit RC2. If any of these algorithms is disabled then it will not be
66 included.
67 PKCS7_sign_add_signers() returns an internal pointer to the
69 PKCS7_SIGNER_INFO structure just added, this can be used to set
70 additional attributes before it is finalized.
71
73 PKCS7_sign_add_signers() returns an internal pointer to the
74 PKCS7_SIGNER_INFO structure just added or NULL if an error occurs.
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77 ERR_get_error(3), PKCS7_sign(3), PKCS7_final(3),
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80 The PPKCS7_sign_add_signer() function was added in OpenSSL 1.0.0.
81
83 Copyright 2007-2016 The OpenSSL Project Authors. All Rights Reserved.
84 Licensed under the OpenSSL license (the "License"). You may not use
86 this file except in compliance with the License. You can obtain a copy
87 in the file LICENSE in the source distribution or at
88 <https://www.openssl.org/source/license.html>.
891.1.1q 2023-07-20 PKCS7_SIGN_ADD_SIGNER(3)