=head1 NAME
-EVP_PKEY_CTX_set_rsa_pss_keygen_md, EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md,
-EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen - RSA PSS signature algorithm
+EVP_PKEY_CTX_set_rsa_pss_keygen_md,
+EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md,
+EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen
+- EVP_PKEY RSA-PSS algorithm support functions
=head1 SYNOPSIS
=head1 DESCRIPTION
-The B<EVP_PKEY_RSA_PSS> algorithm implements the RSA PSS signature algorithm.
-It is a restricted version of the RSA algorithm which only supports signing,
-verification and key generation using PSS padding modes with optional
-parameter restrictions.
+These are the functions that implement L<RSA-PSS(7)>.
-It has associated private key and public key formats.
-
-This algorithm shares several control operations with the B<RSA> algorithm
-but with some restrictions described below.
-
-=head1 SIGNING AND VERIFICATION
-
-Siging and verification is similar to the B<RSA> algorithm except the
-padding mode is always PSS. If the key in use has parameter restrictions then
-the corresponding signature parameters are set to the restrictions:
-for example, if the key can only be used with digest SHA256, MGF1 SHA256
-and minimum salt length 32 then the digest, MGF1 digest and salt length
-will be set to SHA256, SHA256 and 32 respectively.
+=head2 Signing and Verification
The macro EVP_PKEY_CTX_set_rsa_padding() is supported but an error is
returned if an attempt is made to set the padding mode to anything other
The EVP_PKEY_CTX_set_rsa_pss_saltlen() macro is used to set the salt length.
If the key has usage restrictions then an error is returned if an attempt is
made to set the salt length below the minimum value. It is otherwise similar
-to the B<RSA> operation except detection of the salt length (using -2) is
-not supported for verification if the key has usage restrictions.
+to the B<RSA> operation except detection of the salt length (using
+RSA_PSS_SALTLEN_AUTO) is not supported for verification if the key has
+usage restrictions.
The EVP_PKEY_CTX_set_signature_md() and EVP_PKEY_CTX_set_rsa_mgf1_md() macros
are used to set the digest and MGF1 algorithms respectively. If the key has
digest to anything other than the restricted value. Otherwise these are
similar to the B<RSA> versions.
-=head1 KEY GENERATION
+=head2 Key Generation
-As with RSA key generation the EVP_PKEY_CTX_set_rsa_rsa_keygen_bits()
-and EVP_PKEY_CTX_set_rsa_keygen_pubexp() macros are supported for RSA PSS:
+As with RSA key generation the EVP_PKEY_CTX_set_rsa_keygen_bits()
+and EVP_PKEY_CTX_set_rsa_keygen_pubexp() macros are supported for RSA-PSS:
they have exactly the same meaning as for the RSA algorithm.
-Optional parameter restrictions can be specified when generating a PSS key. By
-default no parameter restrictions are placed on the generated key. If any
-restrictions are set (using the macros described below) then B<all> parameters
-are restricted. For example, setting a minimum salt length also restricts the
-digest and MGF1 algorithms. If any restrictions are in place then they are
-reflected in the corresponding parameters of the public key when (for example)
-a certificate request is signed.
+Optional parameter restrictions can be specified when generating a PSS key.
+If any restrictions are set (using the macros described below) then B<all>
+parameters are restricted. For example, setting a minimum salt length also
+restricts the digest and MGF1 algorithms. If any restrictions are in place
+then they are reflected in the corresponding parameters of the public key
+when (for example) a certificate request is signed.
EVP_PKEY_CTX_set_rsa_pss_keygen_md() restricts the digest algorithm the
generated key can use to B<md>.
EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen() restricts the minimum salt length
to B<saltlen>.
+=head1 NOTES
+
+A context for the B<RSA-PSS> algorithm can be obtained by calling:
+
+ EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_RSA_PSS, NULL);
+
=head1 RETURN VALUES
All these functions return 1 for success and 0 or a negative value for failure.
=head1 SEE ALSO
+L<RSA-PSS(7)>,
L<EVP_PKEY_CTX_new(3)>,
L<EVP_PKEY_CTX_ctrl_str(3)>,
L<EVP_PKEY_derive(3)>
=head1 COPYRIGHT
-Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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
L<https://www.openssl.org/source/license.html>.
projects / openssl.git / blobdiff