serpent: Provide little-endian version too, but ours is big

[secnet.git] / serpent.c

diff --git a/serpent.c b/serpent.c
index 34ef6aa4d2a689b5a9282c9ee351088ee48186e9..6407c5776624eef4801685aab34864b238b19614 100644 (file)
--- a/serpent.c
+++ b/serpent.c
@@ -20,12 +20,45 @@
  *
  */
 
-#include "secnet.h"
+#include <stdint.h>
 
 #include "serpent.h"
 #include "serpentsboxes.h"
 
-void serpent_makekey(struct keyInstance *key, int keyLen,
+#ifdef SERPENT_BIGENDIAN
+
+#define GETPUT_CP(bytenum) \
+    (((basep) + (lenbytes) - (offset) - 4)[(bytenum)])
+
+#define SERPENT_DECORATE(func) serpentbe_##func
+
+#else /* !defined(SERPENT_BIGENDIAN) */
+
+#define GETPUT_CP(bytenum) \
+    (((basep) + (offset))[3-(bytenum)])
+
+#define SERPENT_DECORATE(func) serpent_##func
+
+#endif /* !defined(SERPENT_BIGENDIAN) */
+
+static uint32_t serpent_get_32bit(const uint8_t *basep,
+                                 int lenbytes, int offset)
+{
+    return (((uint32_t)GETPUT_CP(0) << 24) |
+           ((uint32_t)GETPUT_CP(1) << 16) |
+           ((uint32_t)GETPUT_CP(2) << +8) |
+           ((uint32_t)GETPUT_CP(3)));
+}
+
+static void serpent_put_32bit(uint8_t *basep, int lenbytes, int offset, uint32_t value)
+{
+    GETPUT_CP(0) = (char)((value) >> 24);
+    GETPUT_CP(1) = (char)((value) >> 16);
+    GETPUT_CP(2) = (char)((value) >> 8);
+    GETPUT_CP(3) = (char)(value);
+}
+
+void SERPENT_DECORATE(makekey)(struct keyInstance *key, int keyLen,
            const uint8_t *keyMaterial)
 {
     int i;
@@ -33,9 +66,9 @@ void serpent_makekey(struct keyInstance *key, int keyLen,
     uint32_t w[132],k[132];
 
     for(i=0; i<keyLen/32; i++)
-       w[i]=GET_32BIT_MSB_FIRST(keyMaterial + (keyLen/8 - i*4) - 4);
+       w[i]=serpent_get_32bit(keyMaterial, keyLen/8, i*4);
     if(keyLen<256)
-       w[i]=(GET_32BIT_MSB_FIRST(keyMaterial + (keyLen/8 - i*4) - 4)
+       w[i]=(serpent_get_32bit(keyMaterial, keyLen/8, i*4)
               & ((1L<<((keyLen&31)))-1)) | (1L<<((keyLen&31)));
     for(i++; i<8; i++)
        w[i]=0;
@@ -85,17 +118,17 @@ void serpent_makekey(struct keyInstance *key, int keyLen,
            key->subkeys[i][j] = k[4*i+j];
 }
 
-void serpent_encrypt(struct keyInstance *key,
+void SERPENT_DECORATE(encrypt)(struct keyInstance *key,
                     const uint8_t plaintext[16], 
                     uint8_t ciphertext[16])
 {
     register uint32_t x0, x1, x2, x3;
     register uint32_t y0, y1, y2, y3;
 
-    x0=GET_32BIT_MSB_FIRST(plaintext+12);
-    x1=GET_32BIT_MSB_FIRST(plaintext+8);
-    x2=GET_32BIT_MSB_FIRST(plaintext+4);
-    x3=GET_32BIT_MSB_FIRST(plaintext);
+    x0=serpent_get_32bit(plaintext,16,+0);
+    x1=serpent_get_32bit(plaintext,16,+4);
+    x2=serpent_get_32bit(plaintext,16,+8);
+    x3=serpent_get_32bit(plaintext,16,12);
 
     /* Start to encrypt the plaintext x */
     keying(x0, x1, x2, x3, key->subkeys[ 0]);
@@ -197,23 +230,23 @@ void serpent_encrypt(struct keyInstance *key,
     keying(x0, x1, x2, x3, key->subkeys[32]);
     /* The ciphertext is now in x */
 
-    PUT_32BIT_MSB_FIRST(ciphertext+12, x0);
-    PUT_32BIT_MSB_FIRST(ciphertext+8, x1);
-    PUT_32BIT_MSB_FIRST(ciphertext+4, x2);
-    PUT_32BIT_MSB_FIRST(ciphertext, x3);
+    serpent_put_32bit(ciphertext,16,+0, x0);
+    serpent_put_32bit(ciphertext,16,+4, x1);
+    serpent_put_32bit(ciphertext,16,+8, x2);
+    serpent_put_32bit(ciphertext,16,12, x3);
 }
 
-void serpent_decrypt(struct keyInstance *key,
+void SERPENT_DECORATE(decrypt)(struct keyInstance *key,
                     const uint8_t ciphertext[16],
                     uint8_t plaintext[16])
 {
     register uint32_t x0, x1, x2, x3;
     register uint32_t y0, y1, y2, y3;
 
-    x0=GET_32BIT_MSB_FIRST(ciphertext+12);
-    x1=GET_32BIT_MSB_FIRST(ciphertext+8);
-    x2=GET_32BIT_MSB_FIRST(ciphertext+4);
-    x3=GET_32BIT_MSB_FIRST(ciphertext);
+    x0=serpent_get_32bit(ciphertext,16,+0);
+    x1=serpent_get_32bit(ciphertext,16,+4);
+    x2=serpent_get_32bit(ciphertext,16,+8);
+    x3=serpent_get_32bit(ciphertext,16,12);
 
     /* Start to decrypt the ciphertext x */
     keying(x0, x1, x2, x3, key->subkeys[32]);
@@ -315,8 +348,8 @@ void serpent_decrypt(struct keyInstance *key,
     keying(x0, x1, x2, x3, key->subkeys[ 0]);
     /* The plaintext is now in x */
 
-    PUT_32BIT_MSB_FIRST(plaintext+12, x0);
-    PUT_32BIT_MSB_FIRST(plaintext+8, x1);
-    PUT_32BIT_MSB_FIRST(plaintext+4, x2);
-    PUT_32BIT_MSB_FIRST(plaintext, x3);
+    serpent_put_32bit(plaintext,16,+0, x0);
+    serpent_put_32bit(plaintext,16,+4, x1);
+    serpent_put_32bit(plaintext,16,+8, x2);
+    serpent_put_32bit(plaintext,16,12, x3);
 }