adding salsa20

[arm-crypto-lib.git] / salsa20 / salsa20.c

diff --git a/salsa20/salsa20.c b/salsa20/salsa20.c
new file mode 100644 (file)
index 0000000..ddd2226
--- /dev/null
+++ b/salsa20/salsa20.c
@@ -0,0 +1,142 @@
+/* salsa20.c */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2006-2011 Daniel Otte (daniel.otte@rub.de)
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdint.h>
+#include <string.h>
+#include "salsa20.h"
+
+
+#define ROTL32(a,n) (((a)<<(n))|((a)>>(32-(n))))
+
+static
+void quaterround(uint32_t* a, uint32_t* b, uint32_t* c, uint32_t* d){
+       *b ^= ROTL32(*a + *d,  7);
+       *c ^= ROTL32(*b + *a,  9);
+       *d ^= ROTL32(*c + *b, 13);
+       *a ^= ROTL32(*d + *c, 18);
+}
+
+static
+void rowround(uint32_t* a){
+       quaterround(a+ 0, a+ 1, a+ 2, a+ 3);
+       quaterround(a+ 5, a+ 6, a+ 7, a+ 4);
+       quaterround(a+10, a+11, a+ 8, a+ 9);
+       quaterround(a+15, a+12, a+13, a+14);
+}
+
+static
+void columnround(uint32_t* a){
+       quaterround(a+ 0, a+ 4, a+ 8, a+12);
+       quaterround(a+ 5, a+ 9, a+13, a+ 1);
+       quaterround(a+10, a+14, a+ 2, a+ 6);
+       quaterround(a+15, a+ 3, a+ 7, a+11);
+}
+
+static
+void doubleround(uint32_t* a){
+       columnround(a);
+       rowround(a);
+
+}
+
+
+void salsa20_hash(uint32_t* a){
+       uint8_t i;
+       uint32_t b[16];
+       memcpy(b, a, 64);
+       for(i=0; i<10; ++i){
+               doubleround(a);
+       }
+       for(i=0; i<16; ++i){
+               a[i] += b[i];
+       }
+}
+
+uint8_t sigma[] = {'e','x','p','a','n','d',' ','3','2','-','b','y','t','e',' ','k'};
+uint8_t theta[] = {'e','x','p','a','n','d',' ','1','6','-','b','y','t','e',' ','k'};
+
+void salsa_k32(uint32_t* dest, const uint32_t* k, const uint32_t* n){
+       memcpy(dest+ 0, sigma+ 0, 4);
+       memcpy(dest+ 4, k+ 0, 16);
+       memcpy(dest+20, sigma+ 4, 4);
+       memcpy(dest+24, n+ 0, 16);
+       memcpy(dest+40, sigma+ 8, 4);
+       memcpy(dest+44, k+16, 16);
+       memcpy(dest+60, sigma+12, 4);
+       salsa20_hash(dest);
+}
+
+void salsa_k16(uint32_t* dest, const uint32_t* k, const uint32_t* n){
+       memcpy(dest+ 0, theta+ 0, 4);
+       memcpy(dest+ 4, k+ 0, 16);
+       memcpy(dest+20, theta+ 4, 4);
+       memcpy(dest+24, n+ 0, 16);
+       memcpy(dest+40, theta+ 8, 4);
+       memcpy(dest+44, k+ 0, 16);
+       memcpy(dest+60, theta+12, 4);
+       salsa20_hash(dest);
+}
+
+void salsa20_genBlock256(void* dest, const void* k, const void* iv, uint64_t i){
+       uint32_t n[4];
+       memcpy(n, iv, 8);
+       memcpy(n+8, &i, 8);
+       salsa_k32((uint32_t*)dest, (uint32_t*)k, n);
+}
+
+void salsa20_genBlock128(void* dest, const void* k, const void* iv, uint64_t i){
+       uint32_t n[4];
+       memcpy(n, iv, 8);
+       memcpy(n+8, &i, 8);
+       salsa_k16((uint32_t*)dest, (uint32_t*)k, n);
+}
+
+
+void salsa20_init(void* key, uint16_t keylength_b, void* iv, salsa20_ctx_t* ctx){
+       if(keylength_b==256){
+               memcpy((ctx->a+ 0), sigma+ 0, 4);
+               memcpy((ctx->a+20), sigma+ 4, 4);
+               memcpy((ctx->a+40), sigma+ 8, 4);
+               memcpy((ctx->a+44), (uint8_t*)key+16, 16);
+               memcpy((ctx->a+60), sigma+12, 4);
+       }else{
+               memcpy((ctx->a+ 0), theta+ 0, 4);
+               memcpy((ctx->a+20), theta+ 4, 4);
+               memcpy((ctx->a+40), theta+ 8, 4);
+               memcpy((ctx->a+44), (uint8_t*)key+ 0, 16);
+               memcpy((ctx->a+60), theta+12, 4);
+       }
+       memcpy((ctx->a+ 4), key, 16);
+       memset((ctx->a+24), 0, 16);
+       if(iv){
+               memcpy((ctx->a+24), iv, 8);
+       }
+       ctx->buffer_idx=64;
+}
+
+uint8_t salsa20_gen(salsa20_ctx_t* ctx){
+       if(ctx->buffer_idx==64){
+               memcpy(ctx->buffer, ctx->a, 64);
+               salsa20_hash((uint32_t*)(ctx->buffer));
+               *((uint64_t*)(ctx->a+32)) += 1;
+               ctx->buffer_idx = 0;
+       }
+       return ctx->buffer[ctx->buffer_idx++];
+}
+