X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=skein%2Fthreefish1024_dec_cstub.c;fp=skein%2Fthreefish1024_dec_cstub.c;h=09b031f634ebaea2db24d5ac1c94f89782bab56e;hb=4f50c75ee5a6cc88bf7ea71957ed509e298e6c25;hp=0000000000000000000000000000000000000000;hpb=7701e318e4e2bac7f84dbf6e368f1501814948fc;p=avr-crypto-lib.git

diff --git a/skein/threefish1024_dec_cstub.c b/skein/threefish1024_dec_cstub.c
new file mode 100644
index 0000000..09b031f
--- /dev/null
+++ b/skein/threefish1024_dec_cstub.c
@@ -0,0 +1,97 @@
+/* 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] = {0x69, 0x72, 0x21, 0x34, 0x42, 0x41, 0x31, 0x79};
+	uint8_t r1[8] = {0x61, 0x19, 0x1a, 0x19, 0x53, 0x10, 0x31, 0x53};
+	uint8_t r2[8] = {0x33, 0x40, 0x22, 0x69, 0x31, 0x22, 0x6a, 0x5b};
+	uint8_t r3[8] = {0x72, 0x6b, 0x31, 0x60, 0x74, 0x71, 0x2b, 0x50};
+	uint8_t r4[8] = {0x5b, 0x23, 0x53, 0x63, 0x54, 0x3b, 0x2a, 0x20};
+	uint8_t r5[8] = {0x60, 0x22, 0x52, 0x11, 0x11, 0x14, 0x2b, 0x3a};
+	uint8_t r6[8] = {0x7b, 0x02, 0x50, 0x43, 0x73, 0x40, 0x64, 0x5a};
+	uint8_t r7[8] = {0x70, 0x70, 0x29, 0x51, 0x42, 0x7a, 0x71, 0x14}; 
+	
+	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);
+}