doc/man7/RSA-PSS.pod - third_party/openssl - Git at Google

 =pod

 =head1 NAME

 RSA-PSS - EVP_PKEY RSA-PSS algorithm support

 =head1 SYNOPSIS

  #include <openssl/rsa.h>

  int EVP_PKEY_CTX_set_rsa_pss_keygen_md(EVP_PKEY_CTX *pctx,
                                         const EVP_MD *md);
  int EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md(EVP_PKEY_CTX *pctx,
                                              const EVP_MD *md);
  int EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen(EVP_PKEY_CTX *pctx,
                                              int saltlen);

 =head1 DESCRIPTION

 The B<RSA-PSS> EVP_PKEY implementation is a restricted version of the RSA
 algorithm which only supports signing, verification and key generation
 using PSS padding modes with optional parameter restrictions.

 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

 Signing 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.

 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
 than B<PSS>. It is otherwise similar to the B<RSA> version.

 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
 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
 usage restrictions then an error is returned if an attempt is made to set the
 digest to anything other than the restricted value. Otherwise these are
 similar to the B<RSA> versions.

 =head1 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:
 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.

 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_mgf1_md() restricts the MGF1 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);

 The public key format is documented in RFC4055.

 The PKCS#8 private key format used for RSA-PSS keys is similar to the RSA
 format except it uses the B<id-RSASSA-PSS> OID and the parameters field, if
 present, restricts the key parameters in the same way as the public key.

 =head1 RETURN VALUES

 All these functions return 1 for success and 0 or a negative value for failure.
 In particular a return value of -2 indicates the operation is not supported by
 the public key algorithm.

 =head1 SEE ALSO

 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.

 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
	=pod

	=head1 NAME

	RSA-PSS - EVP_PKEY RSA-PSS algorithm support

	=head1 SYNOPSIS

	#include <openssl/rsa.h>

	int EVP_PKEY_CTX_set_rsa_pss_keygen_md(EVP_PKEY_CTX *pctx,
	const EVP_MD *md);
	int EVP_PKEY_CTX_set_rsa_pss_keygen_mgf1_md(EVP_PKEY_CTX *pctx,
	const EVP_MD *md);
	int EVP_PKEY_CTX_set_rsa_pss_keygen_saltlen(EVP_PKEY_CTX *pctx,
	int saltlen);

	=head1 DESCRIPTION

	The B<RSA-PSS> EVP_PKEY implementation is a restricted version of the RSA
	algorithm which only supports signing, verification and key generation
	using PSS padding modes with optional parameter restrictions.

	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

	Signing 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.

	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
	than B<PSS>. It is otherwise similar to the B<RSA> version.

	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
	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
	usage restrictions then an error is returned if an attempt is made to set the
	digest to anything other than the restricted value. Otherwise these are
	similar to the B<RSA> versions.

	=head1 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:
	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.

	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_mgf1_md() restricts the MGF1 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);

	The public key format is documented in RFC4055.

	The PKCS#8 private key format used for RSA-PSS keys is similar to the RSA
	format except it uses the B<id-RSASSA-PSS> OID and the parameters field, if
	present, restricts the key parameters in the same way as the public key.

	=head1 RETURN VALUES

	All these functions return 1 for success and 0 or a negative value for failure.
	In particular a return value of -2 indicates the operation is not supported by
	the public key algorithm.

	=head1 SEE ALSO

	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.

	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