improving present

[arm-crypto-lib.git] / present / present_speed.c

diff --git a/present/present_speed.c b/present/present_speed.c
new file mode 100644 (file)
index 0000000..275ec43
--- /dev/null
+++ b/present/present_speed.c
@@ -0,0 +1,102 @@
+/* present.c */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2008  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/>.
+*/
+/**
+ * present.c
+ * a implementation of the PRESENT block-cipher
+ * author: Daniel Otte
+ * email:  daniel.otte@rub.de
+ * license: GPLv3
+ * 
+ * */
+ 
+#include <string.h>
+#include <stdint.h> 
+#include "present_speed.h"
+
+static
+void key_update(uint8_t* buffer, uint8_t round){
+       uint8_t j;
+       union __attribute__((packed)){
+               uint8_t   v8[2];
+               uint16_t v16;
+       } tmp;
+       /* rotate buffer 19 right */
+       tmp.v16 = ((uint16_t*)buffer)[4];
+       j=4;
+       do{
+               ((uint16_t*)buffer)[j] = ((uint16_t*)buffer)[j-1];
+       }while(--j);
+       ((uint16_t*)buffer)[0] = tmp.v16;
+       uint8_t t8;
+       j=0;
+       t8 = (uint16_t)buffer[9] << (5);
+       do{
+               tmp.v8[1] = buffer[j];
+               tmp.v16 >>= 3;
+               buffer[j] = tmp.v8[1] | t8;
+               t8 = tmp.v8[0] & 0xe0;
+       }while(++j<10);
+       /* rotating done now substitution */
+       buffer[0] = (present_sbox(buffer[0])&0xF0) | ((buffer[0])&0x0F);
+       /* xor with round counter */
+       buffer[8] ^= round << 7;
+       buffer[7] ^= round >> 1;
+}
+
+void present_init(const uint8_t* key, uint8_t keysize_b, present_ctx_t* ctx){
+       uint8_t i,key_buffer[10];
+       memcpy(key_buffer, key, 10);
+       memcpy(&(ctx->k[0]), key_buffer, 8);
+       for(i=1; i<32; ++i){
+               key_update(key_buffer, i);
+               memcpy(&(ctx->k[i]), key_buffer, 8);
+       }
+}
+
+
+void present_enc(void* buffer, present_ctx_t* ctx){
+       uint8_t i,j,tmp[8];
+       for(i=0; i<31; ++i){
+               *((uint64_t*)buffer) ^= ctx->k[i];
+               memxor(buffer, &ctx->k[i], 8);
+               j = 7;
+               do{
+                       tmp[j] = present_sbox(((uint8_t*)buffer)[j]);
+               }while(j--);
+               present_p(buffer, tmp);
+       }
+       memxor(buffer, &ctx->k[31], 8);
+}
+
+
+void present_dec(void* buffer, present_ctx_t* ctx){
+       uint8_t j,tmp[8];
+       uint8_t i;
+       memxor(buffer, &ctx->k[31], 8);
+       i = 30;
+       do{
+               present_p(tmp, buffer);
+               present_p(buffer, tmp);
+               j = 7;
+               do{
+                       ((uint8_t*)buffer)[j] = present_sbox_inv(((uint8_t*)buffer)[j]);
+               }while(j--);
+               memxor(buffer, &ctx->k[i], 8);
+       }while(i--);
+}