threefish encrytion in 512 and 1024 bit in assembler

[avr-crypto-lib.git] / threefish512_dec.c

diff --git a/threefish512_dec.c b/threefish512_dec.c
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+++ b/threefish512_dec.c
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+/* threefish512_dec.c */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2009  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/>.
+*/
+/*
+ * \author  Daniel Otte
+ * \email   daniel.otte@rub.de
+ * \date    2009-03-22
+ * \license GPLv3 or later
+ * 
+ * 
+ * 
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include "threefish.h"
+
+
+#define X(a) (((uint64_t*)data)[(a)])
+
+
+static
+void permute_inv8(void* data){
+       uint64_t t;
+       t = X(6);
+       X(6) = X(4);
+       X(4) = X(2);
+       X(2) = X(0);
+       X(0) = t;
+       t = X(7);
+       X(7) = X(3);
+       X(3) = t;
+}
+
+static
+void add_key_8(void* data, const threefish512_ctx_t* ctx, uint8_t s){
+       uint8_t i;
+       for(i=0; i<5; ++i){
+               X(i) -= ctx->k[(s+i)%9];
+       }
+       X(5) -= ctx->k[(s+5)%9] + ctx->t[s%3];
+       X(6) -= ctx->k[(s+6)%9] + ctx->t[(s+1)%3];
+       X(7) -= ctx->k[(s+7)%9] + s;
+}
+
+void threefish512_dec(void* data, const threefish512_ctx_t* ctx){
+       uint8_t i=0,s=18;
+       uint8_t r0[8] = {33, 29, 39, 33, 26, 34, 48, 38}; 
+       uint8_t r1[8] = {51, 26, 27, 49, 12, 14, 20, 30};
+       uint8_t r2[8] = {39, 11, 41,  8, 58, 15, 43, 50};
+       uint8_t r3[8] = {35,  9, 14, 42,  7, 27, 31, 53};
+       do{
+               if(i%4==0){
+                       add_key_8(data, ctx, s);
+                       --s;
+               }
+               permute_inv8(data);
+               threefish_invmix((uint8_t*)data +  0, r0[i%8]);
+               threefish_invmix((uint8_t*)data + 16, r1[i%8]);
+               threefish_invmix((uint8_t*)data + 32, r2[i%8]);
+               threefish_invmix((uint8_t*)data + 48, r3[i%8]);
+               ++i;
+       }while(i!=72);
+       add_key_8(data, ctx, s);
+}
+