113d40330Schristos=pod 213d40330Schristos 313d40330Schristos=head1 NAME 413d40330Schristos 5f30e0929SchristosRSA_private_encrypt, RSA_public_decrypt - low-level signature operations 613d40330Schristos 713d40330Schristos=head1 SYNOPSIS 813d40330Schristos 913d40330Schristos #include <openssl/rsa.h> 1013d40330Schristos 11*b0d17251SchristosThe following functions have been deprecated since OpenSSL 3.0, and can be 12*b0d17251Schristoshidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 13*b0d17251Schristossee L<openssl_user_macros(7)>: 14*b0d17251Schristos 1513d40330Schristos int RSA_private_encrypt(int flen, unsigned char *from, 1613d40330Schristos unsigned char *to, RSA *rsa, int padding); 1713d40330Schristos 1813d40330Schristos int RSA_public_decrypt(int flen, unsigned char *from, 1913d40330Schristos unsigned char *to, RSA *rsa, int padding); 2013d40330Schristos 2113d40330Schristos=head1 DESCRIPTION 2213d40330Schristos 23*b0d17251SchristosBoth of the functions described on this page are deprecated. 24*b0d17251SchristosApplications should instead use L<EVP_PKEY_sign_init_ex(3)>, 25*b0d17251SchristosL<EVP_PKEY_sign(3)>, L<EVP_PKEY_verify_recover_init(3)>, and 26*b0d17251SchristosL<EVP_PKEY_verify_recover(3)>. 27*b0d17251Schristos 28f30e0929SchristosThese functions handle RSA signatures at a low-level. 2913d40330Schristos 3013d40330SchristosRSA_private_encrypt() signs the B<flen> bytes at B<from> (usually a 3113d40330Schristosmessage digest with an algorithm identifier) using the private key 3213d40330SchristosB<rsa> and stores the signature in B<to>. B<to> must point to 3313d40330SchristosB<RSA_size(rsa)> bytes of memory. 3413d40330Schristos 3513d40330SchristosB<padding> denotes one of the following modes: 3613d40330Schristos 3713d40330Schristos=over 4 3813d40330Schristos 3913d40330Schristos=item RSA_PKCS1_PADDING 4013d40330Schristos 4113d40330SchristosPKCS #1 v1.5 padding. This function does not handle the 4213d40330SchristosB<algorithmIdentifier> specified in PKCS #1. When generating or 4313d40330Schristosverifying PKCS #1 signatures, L<RSA_sign(3)> and L<RSA_verify(3)> should be 4413d40330Schristosused. 4513d40330Schristos 4613d40330Schristos=item RSA_NO_PADDING 4713d40330Schristos 4813d40330SchristosRaw RSA signature. This mode should I<only> be used to implement 4913d40330Schristoscryptographically sound padding modes in the application code. 5013d40330SchristosSigning user data directly with RSA is insecure. 5113d40330Schristos 5213d40330Schristos=back 5313d40330Schristos 5413d40330SchristosRSA_public_decrypt() recovers the message digest from the B<flen> 5513d40330Schristosbytes long signature at B<from> using the signer's public key 5613d40330SchristosB<rsa>. B<to> must point to a memory section large enough to hold the 5713d40330Schristosmessage digest (which is smaller than B<RSA_size(rsa) - 5813d40330Schristos11>). B<padding> is the padding mode that was used to sign the data. 5913d40330Schristos 6013d40330Schristos=head1 RETURN VALUES 6113d40330Schristos 6213d40330SchristosRSA_private_encrypt() returns the size of the signature (i.e., 6313d40330SchristosRSA_size(rsa)). RSA_public_decrypt() returns the size of the 6413d40330Schristosrecovered message digest. 6513d40330Schristos 6613d40330SchristosOn error, -1 is returned; the error codes can be 6713d40330Schristosobtained by L<ERR_get_error(3)>. 6813d40330Schristos 6913d40330Schristos=head1 SEE ALSO 7013d40330Schristos 7113d40330SchristosL<ERR_get_error(3)>, 72*b0d17251SchristosL<RSA_sign(3)>, L<RSA_verify(3)>, 73*b0d17251SchristosL<EVP_PKEY_sign(3)>, L<EVP_PKEY_verify_recover(3)> 74*b0d17251Schristos 75*b0d17251Schristos=head1 HISTORY 76*b0d17251Schristos 77*b0d17251SchristosBoth of these functions were deprecated in OpenSSL 3.0. 7813d40330Schristos 7913d40330Schristos=head1 COPYRIGHT 8013d40330Schristos 81*b0d17251SchristosCopyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved. 8213d40330Schristos 83*b0d17251SchristosLicensed under the Apache License 2.0 (the "License"). You may not use 8413d40330Schristosthis file except in compliance with the License. You can obtain a copy 8513d40330Schristosin the file LICENSE in the source distribution or at 8613d40330SchristosL<https://www.openssl.org/source/license.html>. 8713d40330Schristos 8813d40330Schristos=cut 89