| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * The Ed25519 signature scheme |
| 4 | * |
| 5 | * (c) 2017 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Catacomb. |
| 11 | * |
| 12 | * Catacomb is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * Catacomb is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with Catacomb; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | #ifndef CATACOMB_ED25519_H |
| 29 | #define CATACOMB_ED25519_H |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | /*----- Notes on the Ed25519 signature scheme -----------------------------* |
| 36 | * |
| 37 | * This is Ed25519, as described in Daniel J. Bernstein, Neils Duif, Tanja |
| 38 | * Lange, Peter Schwabe, and Bo-Yin Yang, `High-speed high-security |
| 39 | * signatures', CHES 2011, https://ed25519.cr.yp.to/ed25519-20110926.pdf |
| 40 | * |
| 41 | * Specifically, this code implements `PureEdDSA', according to the |
| 42 | * definition in Daniel J. Bernstein, Simon Josefsson, Tanja Lange, Peter |
| 43 | * Schwabe, and Bo-Yin Yang, `EdDSA for more curves', |
| 44 | * https://ed25519.cr.yp.to/eddsa-20150704.pdf. HashEdEDSA can be |
| 45 | * implemented easily by presenting a hash of a message to the functions |
| 46 | * here, as the message to be signed or verified. |
| 47 | */ |
| 48 | |
| 49 | /*----- Header files ------------------------------------------------------*/ |
| 50 | |
| 51 | #include <mLib/bits.h> |
| 52 | |
| 53 | #ifndef CATACOMB_KEY_H |
| 54 | # include "key.h" |
| 55 | #endif |
| 56 | |
| 57 | /*----- Important constants -----------------------------------------------*/ |
| 58 | |
| 59 | #define ED25519_KEYSZ 32u |
| 60 | #define ED25519_PUBSZ 32u |
| 61 | #define ED25519_SIGSZ 64u |
| 62 | |
| 63 | /*----- Key fetching ------------------------------------------------------*/ |
| 64 | |
| 65 | typedef struct ed25519_priv { key_bin priv, pub; } ed25519_priv; |
| 66 | typedef struct ed25519_pub { key_bin pub; } ed25519_pub; |
| 67 | |
| 68 | extern const key_fetchdef ed25519_pubfetch[], ed25519_privfetch[]; |
| 69 | #define ED25519_PUBFETCHSZ 3 |
| 70 | #define ED25519_PRIVFETCHSZ 6 |
| 71 | |
| 72 | /*----- Functions provided ------------------------------------------------*/ |
| 73 | |
| 74 | /* --- @ed25519_pubkey@ --- * |
| 75 | * |
| 76 | * Arguments: @octet K[ED25519_PUBSZ]@ = where to put the public key |
| 77 | * @const void *k@ = private key |
| 78 | * @size_t ksz@ = length of private key |
| 79 | * |
| 80 | * Returns: --- |
| 81 | * |
| 82 | * Use: Derives the public key from a private key. |
| 83 | */ |
| 84 | |
| 85 | extern void ed25519_pubkey(octet /*K*/[ED25519_PUBSZ], |
| 86 | const void */*k*/, size_t /*ksz*/); |
| 87 | |
| 88 | /* --- @ed25519_sign@ --- * |
| 89 | * |
| 90 | * Arguments: @octet sig[ED25519_SIGSZ]@ = where to put the signature |
| 91 | * @const void *k@ = private key |
| 92 | * @size_t ksz@ = length of private key |
| 93 | * @const octet K[ED25519_PUBSZ]@ = public key |
| 94 | * @const void *m@ = message to sign |
| 95 | * @size_t msz@ = length of message |
| 96 | * |
| 97 | * Returns: --- |
| 98 | * |
| 99 | * Use: Signs a message. |
| 100 | */ |
| 101 | |
| 102 | extern void ed25519_sign(octet /*sig*/[ED25519_SIGSZ], |
| 103 | const void */*k*/, size_t /*ksz*/, |
| 104 | const octet /*K*/[ED25519_PUBSZ], |
| 105 | const void */*m*/, size_t /*msz*/); |
| 106 | |
| 107 | /* --- @ed25519_verify@ --- * |
| 108 | * |
| 109 | * Arguments: @const octet K[ED25519_PUBSZ]@ = public key |
| 110 | * @const void *m@ = message to sign |
| 111 | * @size_t msz@ = length of message |
| 112 | * @const octet sig[ED25519_SIGSZ]@ = signature |
| 113 | * |
| 114 | * Returns: Zero if OK, negative on failure. |
| 115 | * |
| 116 | * Use: Verify a signature. |
| 117 | */ |
| 118 | |
| 119 | extern int ed25519_verify(const octet /*K*/[ED25519_PUBSZ], |
| 120 | const void */*m*/, size_t /*msz*/, |
| 121 | const octet /*sig*/[ED25519_SIGSZ]); |
| 122 | |
| 123 | /*----- That's all, folks -------------------------------------------------*/ |
| 124 | |
| 125 | #ifdef __cplusplus |
| 126 | } |
| 127 | #endif |
| 128 | |
| 129 | #endif |