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. If a list entry is preceded 37with the C<?> character, it will be ignored if an implementation is missing. 38 39 40SSL_CTX_set1_client_sigalgs(), SSL_set1_client_sigalgs(), 41SSL_CTX_set1_client_sigalgs_list() and SSL_set1_client_sigalgs_list() set 42signature algorithms related to client authentication, otherwise they are 43identical to SSL_CTX_set1_sigalgs(), SSL_set1_sigalgs(), 44SSL_CTX_set1_sigalgs_list() and SSL_set1_sigalgs_list(). 45 46All these functions are implemented as macros. The signature algorithm 47parameter (integer array or string) is not freed: the application should 48free it, if necessary. 49 50=head1 NOTES 51 52If an application wishes to allow the setting of signature algorithms 53as one of many user configurable options it should consider using the more 54flexible SSL_CONF API instead. 55 56The signature algorithms set by a client are used directly in the supported 57signature algorithm in the client hello message. 58 59The supported signature algorithms set by a server are not sent to the 60client but are used to determine the set of shared signature algorithms 61and (if server preferences are set with SSL_OP_CIPHER_SERVER_PREFERENCE) 62their order. 63 64The client authentication signature algorithms set by a server are sent 65in a certificate request message if client authentication is enabled, 66otherwise they are unused. 67 68Similarly client authentication signature algorithms set by a client are 69used to determined the set of client authentication shared signature 70algorithms. 71 72Signature algorithms will neither be advertised nor used if the security level 73prohibits them (for example SHA1 if the security level is 4 or more). 74 75Currently the NID_md5, NID_sha1, NID_sha224, NID_sha256, NID_sha384 and 76NID_sha512 digest NIDs are supported and the public key algorithm NIDs 77EVP_PKEY_RSA, EVP_PKEY_RSA_PSS, EVP_PKEY_DSA and EVP_PKEY_EC. 78 79The short or long name values for digests can be used in a string (for 80example "MD5", "SHA1", "SHA224", "SHA256", "SHA384", "SHA512") and 81the public key algorithm strings "RSA", "RSA-PSS", "DSA" or "ECDSA". 82 83The TLS 1.3 signature scheme names (such as "rsa_pss_pss_sha256") can also 84be used with the B<_list> forms of the API. 85 86The use of MD5 as a digest is strongly discouraged due to security weaknesses. 87 88=head1 RETURN VALUES 89 90All these functions return 1 for success and 0 for failure. 91 92=head1 EXAMPLES 93 94Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA 95using an array: 96 97 const int slist[] = {NID_sha256, EVP_PKEY_EC, NID_sha256, EVP_PKEY_RSA}; 98 99 SSL_CTX_set1_sigalgs(ctx, slist, 4); 100 101Set supported signature algorithms to SHA256 with ECDSA and SHA256 with RSA 102using a string: 103 104 SSL_CTX_set1_sigalgs_list(ctx, "ECDSA+SHA256:RSA+SHA256"); 105 106=head1 SEE ALSO 107 108L<ssl(7)>, L<SSL_get_shared_sigalgs(3)>, 109L<SSL_CONF_CTX_new(3)> 110 111=head1 HISTORY 112 113Support for ignoring unknown signature algorithms in 114SSL_CTX_set1_sigalgs_list(), SSL_set1_sigalgs_list(), 115SSL_CTX_set1_client_sigalgs_list() and SSL_set1_client_sigalgs_list() 116was added in OpenSSL 3.3. 117 118=head1 COPYRIGHT 119 120Copyright 2015-2024 The OpenSSL Project Authors. All Rights Reserved. 121 122Licensed under the Apache License 2.0 (the "License"). You may not use 123this file except in compliance with the License. You can obtain a copy 124in the file LICENSE in the source distribution or at 125L<https://www.openssl.org/source/license.html>. 126 127=cut 128