X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/4ab1268f3ec850a115a68966325aced4f08ec603..07290a455e008c37adc233554eff8ad468608161:/rc4.c diff --git a/rc4.c b/rc4.c index a4e595f..83b5104 100644 --- a/rc4.c +++ b/rc4.c @@ -1,13 +1,13 @@ /* -*-c-*- * - * $Id: rc4.c,v 1.3 1999/12/13 15:34:01 mdw Exp $ + * $Id: rc4.c,v 1.6 2004/04/08 01:36:15 mdw Exp $ * * The alleged RC4 stream cipher * * (c) 1999 Straylight/Edgeware */ -/*----- Licensing notice --------------------------------------------------* +/*----- Licensing notice --------------------------------------------------* * * This file is part of Catacomb. * @@ -15,32 +15,18 @@ * it under the terms of the GNU Library General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. - * + * * Catacomb is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Library General Public License for more details. - * + * * You should have received a copy of the GNU Library General Public * License along with Catacomb; if not, write to the Free * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */ -/*----- Revision history --------------------------------------------------* - * - * $Log: rc4.c,v $ - * Revision 1.3 1999/12/13 15:34:01 mdw - * Add support for seeding from a generic pseudorandom source. - * - * Revision 1.2 1999/12/10 23:27:35 mdw - * Generic cipher and RNG interfaces. - * - * Revision 1.1 1999/09/03 08:41:12 mdw - * Initial import. - * - */ - /*----- Header files ------------------------------------------------------*/ #include @@ -50,35 +36,38 @@ #include #include +#include "arena.h" #include "gcipher.h" #include "grand.h" +#include "paranoia.h" #include "rc4.h" +/*----- Global variables --------------------------------------------------*/ + +const octet rc4_keysz[] = { KSZ_RANGE, RC4_KEYSZ, 1, 255, 1 }; + /*----- Main code ---------------------------------------------------------*/ -/* --- @rc4_init@ --- * +/* --- @rc4_addkey@ --- * * - * Arguments: @rc4_ctx *ctx@ = pointer to context to initialize + * Arguments: @rc4_ctx *ctx@ = pointer to context to key * @const void *k@ = pointer to key data to use * @size_t sz@ = size of the key data * * Returns: --- * - * Use: Initializes an RC4 context ready for use. + * Use: Mixes key data with an RC4 context. The RC4 context is not + * reset before mixing. This may be used to mix new key + * material with an existing RC4 context. */ -void rc4_init(rc4_ctx *ctx, const void *k, size_t sz) +void rc4_addkey(rc4_ctx *ctx, const void *k, size_t sz) { unsigned i, j; const octet *p = k, *q = p + sz; - assert(((void)"RC4 does not support zero length keys", sz != 0)); + KSZ_ASSERT(rc4, sz); - for (i = 0; i < 256; i++) - ctx->s[i] = i; - ctx->f = 0; - ctx->i = ctx->j = 0; - for (i = j = 0; i < 256; i++) { unsigned si = ctx->s[i]; j = (j + si + *p++) & 0xff; @@ -87,6 +76,29 @@ void rc4_init(rc4_ctx *ctx, const void *k, size_t sz) if (p == q) p = k; } + + ctx->i = ctx->j = 0; +} + +/* --- @rc4_init@ --- * + * + * Arguments: @rc4_ctx *ctx@ = pointer to context to initialize + * @const void *k@ = pointer to key data to use + * @size_t sz@ = size of the key data + * + * Returns: --- + * + * Use: Initializes an RC4 context ready for use. + */ + +void rc4_init(rc4_ctx *ctx, const void *k, size_t sz) +{ + unsigned i; + + for (i = 0; i < 256; i++) + ctx->s[i] = i; + ctx->f = 0; + rc4_addkey(ctx, k, sz); } /* --- @rc4_encrypt@ --- * @@ -131,7 +143,7 @@ static const gcipher_ops gops; static gcipher *ginit(const void *k, size_t sz) { - gctx *g = CREATE(gctx); + gctx *g = S_CREATE(gctx); g->c.ops = &gops; rc4_init(&g->rc4, k, sz); return (&g->c); @@ -146,16 +158,17 @@ static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) static void gdestroy(gcipher *c) { gctx *g = (gctx *)c; - DESTROY(g); + BURN(*g); + S_DESTROY(g); } static const gcipher_ops gops = { - &rc4.b, + &rc4, gencrypt, gencrypt, gdestroy, 0, 0 }; const gccipher rc4 = { - { "rc4", 0, 0 }, + "rc4", rc4_keysz, 0, ginit }; @@ -169,7 +182,8 @@ typedef struct grctx { static void grdestroy(grand *r) { grctx *g = (grctx *)r; - DESTROY(g); + BURN(*g); + S_DESTROY(g); } static int grmisc(grand *r, unsigned op, ...) @@ -177,6 +191,7 @@ static int grmisc(grand *r, unsigned op, ...) grctx *g = (grctx *)r; va_list ap; int rc = 0; + uint32 i; octet buf[4]; va_start(ap, op); @@ -196,23 +211,25 @@ static int grmisc(grand *r, unsigned op, ...) } break; case GRAND_SEEDINT: - STORE32(buf, va_arg(ap, unsigned)); - rc4_init(&g->rc4, buf, sizeof(buf)); + i = va_arg(ap, unsigned); + STORE32(buf, i); + rc4_addkey(&g->rc4, buf, sizeof(buf)); break; case GRAND_SEEDUINT32: - STORE32(buf, va_arg(ap, uint32)); - rc4_init(&g->rc4, buf, sizeof(buf)); + i = va_arg(ap, uint32); + STORE32(buf, i); + rc4_addkey(&g->rc4, buf, sizeof(buf)); break; case GRAND_SEEDBLOCK: { const void *p = va_arg(ap, const void *); size_t sz = va_arg(ap, size_t); - rc4_init(&g->rc4, p, sz); + rc4_addkey(&g->rc4, p, sz); } break; case GRAND_SEEDRAND: { grand *rr = va_arg(ap, grand *); octet buf[16]; rr->ops->fill(rr, buf, sizeof(buf)); - rc4_init(&g->rc4, buf, sizeof(buf)); + rc4_addkey(&g->rc4, buf, sizeof(buf)); } break; default: GRAND_BADOP; @@ -250,7 +267,7 @@ static void grfill(grand *r, void *p, size_t sz) static const grand_ops grops = { "rc4", - 0, + GRAND_CRYPTO, 0, grmisc, grdestroy, grword, grbyte, grword, grand_range, grfill }; @@ -268,7 +285,7 @@ static const grand_ops grops = { grand *rc4_rand(const void *k, size_t sz) { - grctx *g = CREATE(grctx); + grctx *g = S_CREATE(grctx); g->r.ops = &grops; rc4_init(&g->rc4, k, sz); return (&g->r); @@ -298,7 +315,7 @@ static int v_encrypt(dstr *v) if (memcmp(v[2].buf, d.buf, d.len) != 0) { ok = 0; printf("\nfail encryption:" - "\n\tkey = "); + "\n\tkey = "); type_hex.dump(&v[0], stdout); printf("\n\tplaintext = "); type_hex.dump(&v[1], stdout); printf("\n\texpected = "); type_hex.dump(&v[2], stdout); @@ -324,7 +341,7 @@ static int v_generate(dstr *v) if (memcmp(v[2].buf, d.buf, d.len) != 0) { ok = 0; printf("\nfail generation:" - "\n\tkey = "); + "\n\tkey = "); type_hex.dump(&v[0], stdout); printf("\n\tskip len = %i", *(int *)v[1].buf); printf("\n\texpected = "); type_hex.dump(&v[2], stdout);