~mdw / catacomb / blame
| Commit | Line | Data |
|---|---|---|
| aac19f0d MW |
1 | /* -*-c-*- |
| 2 | * | |
| 3 | * AEAD schemes based on Salsa20/ChaCha and Poly1305 | |
| 4 | * | |
| 5 | * (c) 2018 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 it | |
| 13 | * under the terms of the GNU Library General Public License as published | |
| 14 | * by the Free Software Foundation; either version 2 of the License, or | |
| 15 | * (at your option) any later version. | |
| 16 | * | |
| 17 | * Catacomb is distributed in the hope that it will be useful, but | |
| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 20 | * 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 Software | |
| 24 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, | |
| 25 | * USA. | |
| 26 | */ | |
| 27 | ||
| 28 | /*----- Header files ------------------------------------------------------*/ | |
| 29 | ||
| 30 | #include "config.h" | |
| 31 | ||
| 32 | #include <mLib/bits.h> | |
| 33 | #include <mLib/buf.h> | |
| 34 | ||
| 35 | #include "gaead.h" | |
| 36 | #include "keysz.h" | |
| 37 | #include "latinpoly-def.h" | |
| 38 | ||
| 39 | #include "poly1305.h" | |
| 40 | #include "salsa20.h" | |
| 41 | ||
| 42 | /*----- Common definitions ------------------------------------------------*/ | |
| 43 | ||
| 44 | const octet | |
| 45 | latinpoly_noncesz[] = { KSZ_SET, SALSA20_NONCESZ, SALSA20_IETF_NONCESZ, | |
| 46 | XSALSA20_NONCESZ, 0 }, | |
| 47 | latinpoly_tagsz[] = { KSZ_SET, POLY1305_TAGSZ, 0 }; | |
| 48 | ||
| 49 | /* AAD handling. */ | |
| 50 | ||
| 0cf9e22f | 51 | void latinpoly_aadhash_poly1305(gaead_aad *a, const void *h, size_t hsz) |
| aac19f0d MW |
52 | { |
| 53 | latinpoly_aad *aad = (latinpoly_aad *)a; | |
| 54 | poly1305_hash(&aad->poly, h, hsz); | |
| 55 | } | |
| 56 | ||
| 459d1a80 MW |
57 | void latinpoly_aadhash_naclbox(gaead_aad *a, const void *h, size_t hsz) |
| 58 | { assert(!hsz); } | |
| 59 | ||
| aac19f0d MW |
60 | void latinpoly_aaddestroy(gaead_aad *a) { ; } |
| 61 | ||
| 62 | /* --- @latinpoly_tag@ --- * | |
| 63 | * | |
| 64 | * Arguments: @const poly1305_ctx *aad@ = Poly1305 context hashing AAD | |
| 65 | * @poly1305_ctx *ct@ = Poly1305 context hashing ciphertext | |
| 66 | * @void *tag@ = where to write the tag | |
| 67 | * | |
| 68 | * Returns: --- | |
| 69 | * | |
| 70 | * Use: Completes a Latin-dance-Poly1305 tag, combining the AAD and | |
| 71 | * ciphertext hashes, appending their lengths, and writing the | |
| 72 | * final masked hash to @tag@. The @ct@ context is clobbered. | |
| 73 | */ | |
| 74 | ||
| 75 | /* Write the length of data pushed through Poly1305 as a 64-bit integer. */ | |
| 76 | static void putlen(octet *p, const poly1305_ctx *poly) | |
| 77 | { | |
| 78 | uint32 lo = U32((poly->count << 4) | poly->nbuf), | |
| 79 | hi = U32(poly->count >> 28); | |
| 80 | STORE32_L(p + 0, lo); STORE32_L(p + 4, hi); | |
| 81 | } | |
| 82 | ||
| 83 | void latinpoly_tag(const poly1305_ctx *aad, poly1305_ctx *ct, void *tag) | |
| 84 | { | |
| 85 | octet b[16]; | |
| 86 | poly1305_ctx t; | |
| 87 | ||
| 88 | putlen(b + 8, ct); poly1305_flushzero(ct); | |
| 89 | if (!aad) memset(b, 0, 8); | |
| 90 | else { | |
| 91 | putlen(b + 0, aad); | |
| 92 | t = *aad; poly1305_flushzero(&t); poly1305_concat(ct, &t, ct); | |
| 93 | } | |
| 94 | poly1305_hash(ct, b, 16); poly1305_done(ct, tag); | |
| 95 | } | |
| 96 | ||
| 97 | /*----- That's all, folks -------------------------------------------------*/ |