1=pod 2 3=head1 NAME 4 5SSL_CTX_set1_sigalgs, SSL_set1_sigalgs, SSL_CTX_set1_sigalgs_list, 6SSL_set1_sigalgs_list, SSL_CTX_set1_client_sigalgs, 7SSL_set1_client_sigalgs, SSL_CTX_set1_client_sigalgs_list, 8SSL_set1_client_sigalgs_list - set supported signature algorithms 9 10=head1 SYNOPSIS 11 12 #include <openssl/ssl.h> 13 14 long SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *slist, long slistlen); 15 long SSL_set1_sigalgs(SSL *ssl, const int *slist, long slistlen); 16 long SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str); 17 long SSL_set1_sigalgs_list(SSL *ssl, const char *str); 18 19 long SSL_CTX_set1_client_sigalgs(SSL_CTX *ctx, const int *slist, long slistlen); 20 long SSL_set1_client_sigalgs(SSL *ssl, const int *slist, long slistlen); 21 long SSL_CTX_set1_client_sigalgs_list(SSL_CTX *ctx, const char *str); 22 long SSL_set1_client_sigalgs_list(SSL *ssl, const char *str); 23 24=head1 DESCRIPTION 25 26SSL_CTX_set1_sigalgs() and SSL_set1_sigalgs() set the supported signature 27algorithms for B<ctx> or B<ssl>. The array B<slist> of length B<slistlen> 28must consist of pairs of NIDs corresponding to digest and public key 29algorithms. 30 31SSL_CTX_set1_sigalgs_list() and SSL_set1_sigalgs_list() set the supported 32signature algorithms for B<ctx> or B<ssl>. The B<str> parameter 33must be a null terminated string consisting of a colon separated list of 34elements, where each element is either a combination of a public key 35algorithm and a digest separated by B<+>, or a TLS 1.3-style named 36SignatureScheme such as rsa_pss_pss_sha256. 37 38SSL_CTX_set1_client_sigalgs(), SSL_set1_client_sigalgs(), 39SSL_CTX_set1_client_sigalgs_list() and SSL_set1_client_sigalgs_list() set 40signature algorithms related to client authentication, otherwise they are 41identical to SSL_CTX_set1_sigalgs(), SSL_set1_sigalgs(), 42SSL_CTX_set1_sigalgs_list() and SSL_set1_sigalgs_list(). 43 44All these functions are implemented as macros. The signature algorithm 45parameter (integer array or string) is not freed: the application should 46free it, if necessary. 47 48=head1 NOTES 49 50If an application wishes to allow the setting of signature algorithms 51as one of many user configurable options it should consider using the more 52flexible SSL_CONF API instead. 53 54The signature algorithms set by a client are used directly in the supported 55signature algorithm in the client hello message. 56 57The supported signature algorithms set by a server are not sent to the 58client but are used to determine the set of shared signature algorithms 59and (if server preferences are set with SSL_OP_CIPHER_SERVER_PREFERENCE) 60their order. 61 62The client authentication signature algorithms set by a server are sent 63in a certificate request message if client authentication is enabled, 64otherwise they are unused. 65 66Similarly client authentication signature algorithms set by a client are 67used to determined the set of client authentication shared signature 68algorithms. 69 70Signature algorithms will neither be advertised nor used if the security level 71prohibits them (for example SHA1 if the security level is 4 or more). 72 73Currently the NID_md5, NID_sha1, NID_sha224, NID_sha256, NID_sha384 and 74NID_sha512 digest NIDs are supported and the public key algorithm NIDs 75EVP_PKEY_RSA, EVP_PKEY_RSA_PSS, EVP_PKEY_DSA and EVP_PKEY_EC. 76 77The short or long name values for digests can be used in a string (for 78example "MD5", "SHA1", "SHA224", "SHA256", "SHA384", "SHA512") and 79the public key algorithm strings "RSA", "RSA-PSS", "DSA" or "ECDSA". 80 81The TLS 1.3 signature scheme names (such as "rsa_pss_pss_sha256") can also 82be used with the B<_list> forms of the API. 83 84The use of MD5 as a digest is strongly discouraged due to security weaknesses. 85 86=head1 RETURN VALUES 87 88All these functions return 1 for success and 0 for failure. 89 90=head1 EXAMPLES 91 92Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA 93using an array: 94 95 const int slist[] = {NID_sha256, EVP_PKEY_EC, NID_sha256, EVP_PKEY_RSA}; 96 97 SSL_CTX_set1_sigalgs(ctx, slist, 4); 98 99Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA 100using a string: 101 102 SSL_CTX_set1_sigalgs_list(ctx, "ECDSA+SHA256:RSA+SHA256"); 103 104=head1 SEE ALSO 105 106L<ssl(7)>, L<SSL_get_shared_sigalgs(3)>, 107L<SSL_CONF_CTX_new(3)> 108 109=head1 COPYRIGHT 110 111Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. 112 113Licensed under the Apache License 2.0 (the "License"). You may not use 114this file except in compliance with the License. You can obtain a copy 115in the file LICENSE in the source distribution or at 116L<https://www.openssl.org/source/license.html>. 117 118=cut 119