fixing E-Mail-Address & Copyright

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

diff --git a/skipjack/skipjack.c b/skipjack/skipjack.c
index 04eb437a00edb18d2bc77ffae2cf5ffa974f4c5a..68187ce079222f8684ca276199accebf05c2b46f 100644 (file)
--- a/skipjack/skipjack.c
+++ b/skipjack/skipjack.c
@@ -1,7 +1,7 @@
 /* skipjack.c */
 /*
     This file is part of the AVR-Crypto-Lib.
-    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+    Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
 
     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
@@ -30,9 +30,13 @@
 #include <avr/io.h>
 #include <avr/pgmspace.h>
 
-#define SKIPJACK_CNT_BIG
+#if NESSIE_COMPAT
+#define SKIPJACK_CNT_BIG 1
+#else
+#define SKIPJACK_CNT_BIG 0
+#endif
 
-#ifdef SKIPJACK_CNT_BIG
+#if SKIPJACK_CNT_BIG
   #define SKIPJACK_CNT_SHIFT <<8
 #else
   #define SKIPJACK_CNT_SHIFT
@@ -40,7 +44,7 @@
 
 /*****************************************************************************/
 
-uint8_t skipjack_ftable[] PROGMEM ={ 
+const uint8_t skipjack_ftable[] PROGMEM ={ 
        0xa3, 0xd7, 0x09, 0x83, 0xf8, 0x48, 0xf6, 0xf4, 
        0xb3, 0x21, 0x15, 0x78, 0x99, 0xb1, 0xaf, 0xf9, 
        0xe7, 0x2d, 0x4d, 0x8a, 0xce, 0x4c, 0xca, 0x2e, 
@@ -76,74 +80,80 @@ uint8_t skipjack_ftable[] PROGMEM ={
 };
 
 /*****************************************************************************/
+static
+uint16_t skipjack_sub_g(uint8_t g, uint8_t k, uint8_t *key){
+       return pgm_read_byte(&(skipjack_ftable[g ^ key[9 - k % 10]]));
+}
 
+static
 uint16_t skipjack_g(uint16_t g, uint8_t k, uint8_t *key){
-       #define G1 (((uint8_t*)&g)[0])
-       #define G2 (((uint8_t*)&g)[1])
+       #define G1 (((uint8_t*)&g)[1])
+       #define G2 (((uint8_t*)&g)[0])
        /* this could also be rolled up */
-       G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+0)%10]]));
-       G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+1)%10]]));
-       G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+2)%10]]));
-       G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+3)%10]]));
+       k *= 4;
+       G1 ^= skipjack_sub_g(G2, k + 0, key);
+       G2 ^= skipjack_sub_g(G1, k + 1, key);
+       G1 ^= skipjack_sub_g(G2, k + 2, key);
+       G2 ^= skipjack_sub_g(G1, k + 3, key);
        return g;       
 }
 
 /*****************************************************************************/
-
+static
 uint16_t skipjack_g_inv(uint16_t g, uint8_t k, uint8_t *key){
 //     #define G1 (((uint8_t)&g)[1])
 //     #define G2 (((uint8_t)&g)[0])
        /* this could also be rolled up */
-       G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+3)%10]]));
-       G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+2)%10]]));
-       G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+1)%10]]));
-       G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+0)%10]]));
-       return g;       
+       k *= 4;
+       G2 ^= skipjack_sub_g(G1, k + 3, key);
+       G1 ^= skipjack_sub_g(G2, k + 2, key);
+       G2 ^= skipjack_sub_g(G1, k + 1, key);
+       G1 ^= skipjack_sub_g(G2, k + 0, key);
+       return g;
 }
 
 /*****************************************************************************/
-
-void skipjack_a(uint16_t* w, uint8_t k, uint8_t* key){
+static
+void skipjack_a(uint16_t *w, uint8_t k, uint8_t *key){
        uint16_t t;
-
-       t = w[3];
-       w[3] = w[2];
-       w[2] = w[1];
-       w[1] = skipjack_g(w[0],k-1,key);
-       w[0] = t ^ w[1] ^ (((uint16_t)k)SKIPJACK_CNT_SHIFT);
+       t = w[0];
+       w[0] = w[1];
+       w[1] = w[2];
+       w[2] = skipjack_g(w[3],k,key);
+       w[3] = t ^ w[2] ^ (((uint16_t)k+1)SKIPJACK_CNT_SHIFT);
 }
 
 /*****************************************************************************/
-
-void skipjack_a_inv(uint16_t* w, uint8_t k, uint8_t* key){
+static
+void skipjack_a_inv(uint16_t *w, uint8_t k, uint8_t *key){
        uint16_t t;
-       t = w[0] ^ w[1];
-       w[0] = skipjack_g_inv(w[1],k-1,key);
-       w[1] = w[2];
-       w[2] = w[3];
-       w[3] = t ^ (((uint16_t)k)SKIPJACK_CNT_SHIFT);
+       t = w[3] ^ w[2];
+       w[3] = skipjack_g_inv(w[2],k,key);
+       w[2] = w[1];
+       w[1] = w[0];
+       w[0] = t ^ (((uint16_t)k+1)SKIPJACK_CNT_SHIFT);
 }
 
 /*****************************************************************************/
-
-void skipjack_b(uint16_t* w, uint8_t k, uint8_t* key){
+static
+void skipjack_b(uint16_t *w, uint8_t k, uint8_t *key){
        uint16_t t;
-       t = w[0];
-       w[0] = w[3];
-       w[3] = w[2];
-       w[2] = t ^ (((uint16_t)k)SKIPJACK_CNT_SHIFT) ^ w[1];
-       w[1] = skipjack_g(t,k-1,key);
+       t = w[3];
+       w[3] = w[0];
+       w[0] = w[1];
+       w[1] = t ^ (((uint16_t)k+1)SKIPJACK_CNT_SHIFT) ^ w[2];
+       w[2] = skipjack_g(t,k,key);
 }
 
 /*****************************************************************************/
-
-void skipjack_b_inv(uint16_t* w, uint8_t k, uint8_t* key){
+static
+void skipjack_b_inv(uint16_t *w, uint8_t k, uint8_t *key){
        uint16_t t;
-       t = w[2];
-       w[2] = w[3];
-       w[3] = w[0];
-       w[0] = skipjack_g_inv(w[1],k-1,key);
-       w[1] = w[0] ^ t ^ (((uint16_t)k)SKIPJACK_CNT_SHIFT);
+       t = w[1];
+       w[1] = w[0];
+       w[0] = w[3];
+       w[3] = skipjack_g_inv(w[2],k,key);
+       w[2] = w[3] ^ t ^ (((uint16_t)k+1)SKIPJACK_CNT_SHIFT);
 }
 
 /*****************************************************************************/
@@ -151,29 +161,28 @@ void skipjack_b_inv(uint16_t* w, uint8_t k, uint8_t* key){
  * block is 64 bits (=8 bytes) in size, key is 80 bits (=10 bytes) in size.
  * 
  */
-void skipjack_enc(void* block, void* key){
+void skipjack_enc(void *block, void *key){
        uint8_t k;
        for(k=0; k<32; ++k){
                if(k & 0x08){
-                       skipjack_b((uint16_t*)block, k+1, key);
+                       skipjack_b((uint16_t*)block, k, key);
                } else {
-                       skipjack_a((uint16_t*)block, k+1, key);
+                       skipjack_a((uint16_t*)block, k, key);
                }
        }
 }
-
 /*****************************************************************************/
 /**
  * block is 64 bits (=8 bytes) in size, key is 80 bits (=10 bytes) in size.
  * 
  */
-void skipjack_dec(void* block, void* key){
+void skipjack_dec(void *block, void *key){
        int8_t k;
        for(k=31; k>=0; --k){
                if(k & 0x08){
-                       skipjack_b_inv((uint16_t*)block, k+1, key);
+                       skipjack_b_inv((uint16_t*)block, k, key);
                } else {
-                       skipjack_a_inv((uint16_t*)block, k+1, key);
+                       skipjack_a_inv((uint16_t*)block, k, key);
                }
        }
 }