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1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
d8652be0 | 5 | PKCS7_sign_ex, PKCS7_sign |
90a1f2d7 | 6 | - create a PKCS#7 signedData structure |
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7 | |
8 | =head1 SYNOPSIS | |
9 | ||
c264592d UM |
10 | #include <openssl/pkcs7.h> |
11 | ||
d8652be0 | 12 | PKCS7 *PKCS7_sign_ex(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs, |
b4250010 | 13 | BIO *data, int flags, OSSL_LIB_CTX *libctx, |
d8652be0 | 14 | const char *propq); |
e9b77246 BB |
15 | PKCS7 *PKCS7_sign(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs, |
16 | BIO *data, int flags); | |
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17 | |
18 | =head1 DESCRIPTION | |
19 | ||
d8652be0 | 20 | PKCS7_sign_ex() creates and returns a PKCS#7 signedData structure. |
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21 | I<igncert> is the certificate to sign with, Ipkey> is the corresponding |
22 | private key. I<certs> is an optional additional set of certificates to include | |
23 | in the PKCS#7 structure (for example any intermediate CAs in the chain). The | |
24 | library context I<libctx> and property query I<propq> are used when | |
25 | retrieving algorithms from providers. | |
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26 | |
27 | The data to be signed is read from BIO B<data>. | |
28 | ||
29 | B<flags> is an optional set of flags. | |
30 | ||
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31 | Any of the following flags (ored together) can be passed in the B<flags> |
32 | parameter. | |
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33 | |
34 | Many S/MIME clients expect the signed content to include valid MIME headers. If | |
35 | the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended | |
36 | to the data. | |
37 | ||
38 | If B<PKCS7_NOCERTS> is set the signer's certificate will not be included in the | |
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39 | PKCS7 structure, the signer's certificate must still be supplied in the |
40 | B<signcert> parameter though. This can reduce the size of the signature if the | |
41 | signers certificate can be obtained by other means: for example a previously | |
42 | signed message. | |
43 | ||
44 | The data being signed is included in the PKCS7 structure, unless | |
45 | B<PKCS7_DETACHED> is set in which case it is omitted. This is used for PKCS7 | |
46 | detached signatures which are used in S/MIME plaintext signed messages for | |
47 | example. | |
48 | ||
49 | Normally the supplied content is translated into MIME canonical format (as | |
50 | required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation | |
51 | occurs. This option should be used if the supplied data is in binary format | |
52 | otherwise the translation will corrupt it. | |
53 | ||
27b138e9 | 54 | The signedData structure includes several PKCS#7 authenticatedAttributes |
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55 | including the signing time, the PKCS#7 content type and the supported list of |
56 | ciphers in an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no | |
57 | authenticatedAttributes will be used. If B<PKCS7_NOSMIMECAP> is set then just | |
58 | the SMIMECapabilities are omitted. | |
d30e4c5b | 59 | |
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60 | If present the SMIMECapabilities attribute indicates support for the following |
61 | algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of | |
62 | these algorithms is disabled then it will not be included. | |
d30e4c5b | 63 | |
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64 | If the flags B<PKCS7_STREAM> is set then the returned B<PKCS7> structure is |
65 | just initialized ready to perform the signing operation. The signing is however | |
66 | B<not> performed and the data to be signed is not read from the B<data> | |
67 | parameter. Signing is deferred until after the data has been written. In this | |
68 | way data can be signed in a single pass. | |
d30e4c5b | 69 | |
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70 | If the B<PKCS7_PARTIAL> flag is set a partial B<PKCS7> structure is output to |
71 | which additional signers and capabilities can be added before finalization. | |
4e1b50e2 | 72 | |
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73 | If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not> |
74 | complete and outputting its contents via a function that does not properly | |
75 | finalize the B<PKCS7> structure will give unpredictable results. | |
4cadedef | 76 | |
9034c56c | 77 | Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(), |
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78 | PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization |
79 | can be performed by obtaining the streaming ASN1 B<BIO> directly using | |
80 | BIO_new_PKCS7(). | |
4cadedef | 81 | |
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82 | If a signer is specified it will use the default digest for the signing |
83 | algorithm. This is B<SHA1> for both RSA and DSA keys. | |
4e1b50e2 | 84 | |
a528d4f0 | 85 | The B<certs>, B<signcert> and B<pkey> parameters can all be |
4cfb986f | 86 | B<NULL> if the B<PKCS7_PARTIAL> flag is set. One or more signers can be added |
35cb565a | 87 | using the function PKCS7_sign_add_signer(). PKCS7_final() must also be |
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88 | called to finalize the structure if streaming is not enabled. Alternative |
89 | signing digests can also be specified using this method. | |
4e1b50e2 | 90 | |
a528d4f0 | 91 | If B<signcert> and B<pkey> are NULL then a certificates only |
4cfb986f | 92 | PKCS#7 structure is output. |
4e1b50e2 | 93 | |
fb552ac6 | 94 | In versions of OpenSSL before 1.0.0 the B<signcert> and B<pkey> parameters must |
4cfb986f | 95 | B<NOT> be NULL. |
4e1b50e2 | 96 | |
d8652be0 | 97 | PKCS7_sign() is similar to PKCS7_sign_ex() but uses default values of |
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98 | NULL for the library context I<libctx> and the property query I<propq>. |
99 | ||
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100 | =head1 BUGS |
101 | ||
102 | Some advanced attributes such as counter signatures are not supported. | |
4e1b50e2 | 103 | |
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104 | =head1 RETURN VALUES |
105 | ||
d8652be0 | 106 | PKCS7_sign_ex() and PKCS7_sign() return either a valid PKCS7 structure |
90a1f2d7 | 107 | or NULL if an error occurred. The error can be obtained from ERR_get_error(3). |
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108 | |
109 | =head1 SEE ALSO | |
110 | ||
9b86974e | 111 | L<ERR_get_error(3)>, L<PKCS7_verify(3)> |
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112 | |
113 | =head1 HISTORY | |
114 | ||
d8652be0 | 115 | The function PKCS7_sign_ex() was added in OpenSSL 3.0. |
90a1f2d7 | 116 | |
a528d4f0 | 117 | The B<PKCS7_PARTIAL> flag, and the ability for B<certs>, B<signcert>, |
fc5ecadd | 118 | and B<pkey> parameters to be B<NULL> were added in OpenSSL 1.0.0. |
4cfb986f | 119 | |
fc5ecadd | 120 | The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0. |
4cadedef | 121 | |
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122 | =head1 COPYRIGHT |
123 | ||
eec0ad10 | 124 | Copyright 2002-2020 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 | 125 | |
4746f25a | 126 | Licensed under the Apache License 2.0 (the "License"). You may not use |
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127 | this file except in compliance with the License. You can obtain a copy |
128 | in the file LICENSE in the source distribution or at | |
129 | L<https://www.openssl.org/source/license.html>. | |
130 | ||
131 | =cut |