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Diffstat (limited to 'openssl-1.1.0h/doc/crypto/PKCS7_sign.pod')
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diff --git a/openssl-1.1.0h/doc/crypto/PKCS7_sign.pod b/openssl-1.1.0h/doc/crypto/PKCS7_sign.pod new file mode 100644 index 0000000..f319f66 --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/PKCS7_sign.pod @@ -0,0 +1,124 @@ +=pod + +=head1 NAME + +PKCS7_sign - create a PKCS#7 signedData structure + +=head1 SYNOPSIS + + #include <openssl/pkcs7.h> + + PKCS7 *PKCS7_sign(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs, BIO *data, int flags); + +=head1 DESCRIPTION + +PKCS7_sign() creates and returns a PKCS#7 signedData structure. B<signcert> is +the certificate to sign with, B<pkey> is the corresponding private key. +B<certs> is an optional additional set of certificates to include in the PKCS#7 +structure (for example any intermediate CAs in the chain). + +The data to be signed is read from BIO B<data>. + +B<flags> is an optional set of flags. + +=head1 NOTES + +Any of the following flags (ored together) can be passed in the B<flags> +parameter. + +Many S/MIME clients expect the signed content to include valid MIME headers. If +the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended +to the data. + +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 data being signed is included in the PKCS7 structure, unless +B<PKCS7_DETACHED> is set in which case it is omitted. This is used for PKCS7 +detached signatures which are used in S/MIME plaintext signed messages for +example. + +Normally the supplied content is translated into MIME canonical format (as +required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation +occurs. This option should be used if the supplied data is in binary format +otherwise the translation will corrupt it. + +The signedData structure includes several PKCS#7 authenticatedAttributes +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. + +If the flags B<PKCS7_STREAM> is set then the returned B<PKCS7> structure is +just initialized ready to perform the signing operation. The signing is however +B<not> performed and the data to be signed is not read from the B<data> +parameter. Signing is deferred until after the data has been written. In this +way data can be signed in a single pass. + +If the B<PKCS7_PARTIAL> flag is set a partial B<PKCS7> structure is output to +which additional signers and capabilities can be added before finalization. + + +=head1 NOTES + +If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not> +complete and outputting its contents via a function that does not properly +finalize the B<PKCS7> structure will give unpredictable results. + +Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(), +PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization +can be performed by obtaining the streaming ASN1 B<BIO> directly using +BIO_new_PKCS7(). + +If a signer is specified it will use the default digest for the signing +algorithm. This is B<SHA1> for both RSA and DSA keys. + +The B<certs>, B<signcert> and B<pkey> parameters can all be +B<NULL> if the B<PKCS7_PARTIAL> flag is set. One or more signers can be added +using the function PKCS7_sign_add_signer(). PKCS7_final() must also be +called to finalize the structure if streaming is not enabled. Alternative +signing digests can also be specified using this method. + +If B<signcert> and B<pkey> are NULL then a certificates only +PKCS#7 structure is output. + +In versions of OpenSSL before 1.0.0 the B<signcert> and B<pkey> parameters must +B<NOT> be NULL. + +=head1 BUGS + +Some advanced attributes such as counter signatures are not supported. + +=head1 RETURN VALUES + +PKCS7_sign() returns either a valid PKCS7 structure or NULL if an error +occurred. The error can be obtained from ERR_get_error(3). + +=head1 SEE ALSO + +L<ERR_get_error(3)>, L<PKCS7_verify(3)> + +=head1 HISTORY + +The B<PKCS7_PARTIAL> flag, and the ability for B<certs>, B<signcert>, +and B<pkey> parameters to be B<NULL> to be was added in OpenSSL 1.0.0 + +The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0 + +=head1 COPYRIGHT + +Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (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 +L<https://www.openssl.org/source/license.html>. + +=cut |