X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;ds=sidebyside;f=skein%2Fthreefish1024_dec.c;fp=skein%2Fthreefish1024_dec.c;h=edb46d45462d7ff1b48478900076719a17e612bb;hb=4f50c75ee5a6cc88bf7ea71957ed509e298e6c25;hp=0000000000000000000000000000000000000000;hpb=7701e318e4e2bac7f84dbf6e368f1501814948fc;p=avr-crypto-lib.git

diff --git a/skein/threefish1024_dec.c b/skein/threefish1024_dec.c
new file mode 100644
index 0000000..edb46d4
--- /dev/null
+++ b/skein/threefish1024_dec.c
@@ -0,0 +1,96 @@
+/* threefish1024_enc.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    2009-03-12
+ * \license GPLv3 or later
+ * 
+ * 
+ * 
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include "threefish.h"
+
+#define X(a) (((uint64_t*)data)[(a)])
+
+static
+void permute_inv16(void* data){
+	uint64_t t;
+	t = X(15);
+	X(15) = X(7);
+	X(7) = X(9);
+	X(9) = X(1);
+	X(1) = t;
+	t = X(11);
+	X(11) = X(5);
+	X(5) = X(13);
+	X(13) = X(3);
+	X(3) = t; 		
+	t = X(4);
+	X(4) = X(6);
+	X(6) = t;
+	t = X(14);
+	X(14) = X(12);
+	X(12) = X(10);
+	X(10) = X(8);
+	X(8) = t;
+}
+
+static
+void add_key_16(void* data, const threefish1024_ctx_t* ctx, uint8_t s){
+	uint8_t i;
+	for(i=0; i<13; ++i){
+		X(i) -= ctx->k[(s+i)%17];
+	}
+	X(13) -= ctx->k[(s+13)%17] + ctx->t[s%3];
+	X(14) -= ctx->k[(s+14)%17] + ctx->t[(s+1)%3];
+	X(15) -= ctx->k[(s+15)%17] + s;
+}
+
+void threefish1024_dec(void* data, const threefish1024_ctx_t* ctx){
+	uint8_t i=0,s=20;
+	uint8_t r0[8] = {47, 58, 17, 28, 34, 33, 25, 55};
+	uint8_t r1[8] = {49,  7,  6,  7, 43,  8, 25, 43};
+	uint8_t r2[8] = {27, 32, 18, 47, 25, 18, 46, 37};
+	uint8_t r3[8] = {58, 45, 25, 48, 60, 57, 13, 40};
+	uint8_t r4[8] = {37, 19, 43, 51, 44, 21, 14, 16};
+	uint8_t r5[8] = {48, 18, 42,  9,  9, 12, 13, 22};
+	uint8_t r6[8] = {53,  2, 40, 35, 59, 32, 52, 38};
+	uint8_t r7[8] = {56, 56, 15, 41, 34, 54, 57, 12};
+	do{
+		if(i%4==0){
+			add_key_16(data, ctx, s);
+			--s;
+		}
+		permute_inv16(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]);
+		threefish_invmix((uint8_t*)data + 64, r4[i%8]);
+		threefish_invmix((uint8_t*)data + 80, r5[i%8]);
+		threefish_invmix((uint8_t*)data + 96, r6[i%8]);
+		threefish_invmix((uint8_t*)data +112, r7[i%8]);
+		++i;
+	}while(i!=80);
+	add_key_16(data, ctx, s);
+}