projects / thirdparty / openssl.git / blame
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1 | =pod |
| 2 | ||
| 3 | =head1 NAME | |
| 4 | ||
| 4d524e10 | 5 | RSA_private_encrypt, RSA_public_decrypt - low level signature operations |
| 2186cd8e UM |
6 | |
| 7 | =head1 SYNOPSIS | |
| 8 | ||
| 9 | #include <openssl/rsa.h> | |
| 10 | ||
| e9b77246 BB |
11 | int RSA_private_encrypt(int flen, unsigned char *from, |
| 12 | unsigned char *to, RSA *rsa, int padding); | |
| 2186cd8e | 13 | |
| e9b77246 BB |
14 | int RSA_public_decrypt(int flen, unsigned char *from, |
| 15 | unsigned char *to, RSA *rsa, int padding); | |
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16 | |
| 17 | =head1 DESCRIPTION | |
| 18 | ||
| 19 | These functions handle RSA signatures at a low level. | |
| 20 | ||
| 21 | RSA_private_encrypt() signs the B<flen> bytes at B<from> (usually a | |
| 22 | message digest with an algorithm identifier) using the private key | |
| 23 | B<rsa> and stores the signature in B<to>. B<to> must point to | |
| 24 | B<RSA_size(rsa)> bytes of memory. | |
| 25 | ||
| 26 | B<padding> denotes one of the following modes: | |
| 27 | ||
| 28 | =over 4 | |
| 29 | ||
| 30 | =item RSA_PKCS1_PADDING | |
| 31 | ||
| 32 | PKCS #1 v1.5 padding. This function does not handle the | |
| 33 | B<algorithmIdentifier> specified in PKCS #1. When generating or | |
| 9b86974e | 34 | verifying PKCS #1 signatures, L<RSA_sign(3)> and L<RSA_verify(3)> should be |
| 2186cd8e UM |
35 | used. |
| 36 | ||
| 37 | =item RSA_NO_PADDING | |
| 38 | ||
| 39 | Raw RSA signature. This mode should I<only> be used to implement | |
| 40 | cryptographically sound padding modes in the application code. | |
| 41 | Signing user data directly with RSA is insecure. | |
| 42 | ||
| 43 | =back | |
| 44 | ||
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45 | RSA_public_decrypt() recovers the message digest from the B<flen> |
| 46 | bytes long signature at B<from> using the signer's public key | |
| 47 | B<rsa>. B<to> must point to a memory section large enough to hold the | |
| 48 | message digest (which is smaller than B<RSA_size(rsa) - | |
| 49 | 11>). B<padding> is the padding mode that was used to sign the data. | |
| 50 | ||
| 51 | =head1 RETURN VALUES | |
| 52 | ||
| 53 | RSA_private_encrypt() returns the size of the signature (i.e., | |
| 54 | RSA_size(rsa)). RSA_public_decrypt() returns the size of the | |
| 55 | recovered message digest. | |
| 56 | ||
| 57 | On error, -1 is returned; the error codes can be | |
| 9b86974e | 58 | obtained by L<ERR_get_error(3)>. |
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59 | |
| 60 | =head1 SEE ALSO | |
| 61 | ||
| 53934822 | 62 | L<ERR_get_error(3)>, |
| 9b86974e | 63 | L<RSA_sign(3)>, L<RSA_verify(3)> |
| 2186cd8e | 64 | |
| e2f92610 RS |
65 | =head1 COPYRIGHT |
| 66 | ||
| 67 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
| 68 | ||
| 4746f25a | 69 | Licensed under the Apache License 2.0 (the "License"). You may not use |
| e2f92610 RS |
70 | this file except in compliance with the License. You can obtain a copy |
| 71 | in the file LICENSE in the source distribution or at | |
| 72 | L<https://www.openssl.org/source/license.html>. | |
| 73 | ||
| 74 | =cut |