Allow the number of rounds to be configured. This isn't exported

through the gcipher interface, but it may be useful anyway.

diff --git a/tea.c b/tea.c
index 90d97cb..2043337 100644 (file)
--- a/tea.c
+++ b/tea.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: tea.c,v 1.1 2000/07/15 13:44:31 mdw Exp $
+ * $Id: tea.c,v 1.2 2000/07/29 09:56:47 mdw Exp $
  *
  * The Tiny Encryption Algorithm
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: tea.c,v $
+ * Revision 1.2  2000/07/29 09:56:47  mdw
+ * Allow the number of rounds to be configured.  This isn't exported
+ * through the gcipher interface, but it may be useful anyway.
+ *
  * Revision 1.1  2000/07/15 13:44:31  mdw
  * New ciphers.
  *
@@ -76,8 +80,9 @@ void tea_init(tea_ctx *k, const void *buf, size_t sz)
     p = kb;
   }
 
-  k->ka = LOAD32(p +  0);   k->kb = LOAD32(p +  4);
-  k->kc = LOAD32(p +  8);   k->kd = LOAD32(p + 12);
+  k->ka = LOAD32(p +  0); k->kb = LOAD32(p +  4);
+  k->kc = LOAD32(p +  8); k->kd = LOAD32(p + 12);
+  k->r = 32;
 
   if (p == kb)
     BURN(kb);
@@ -103,7 +108,7 @@ void tea_eblk(const tea_ctx *k, const uint32 *s, uint32 *d)
   uint32 n = 0;
   unsigned i;
 
-  for (i = 0; i < 32; i++) {
+  for (i = 0; i < k->r; i++) {
     n += DELTA;
     y = U32(y + (((z << 4) + ka) ^ (z + n) ^ ((z >> 5) + kb)));
     z = U32(z + (((y << 4) + kc) ^ (y + n) ^ ((y >> 5) + kd)));
@@ -115,10 +120,10 @@ void tea_dblk(const tea_ctx *k, const uint32 *s, uint32 *d)
 {
   uint32 y = s[0], z = s[1];
   uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd;
-  uint32 n = DELTA << 5;
+  uint32 n = DELTA * k->r;
   unsigned i;
 
-  for (i = 0; i < 32; i++) {
+  for (i = 0; i < k->r; i++) {
     z = U32(z - (((y << 4) + kc) ^ (y + n) ^ ((y >> 5) + kd)));
     y = U32(y - (((z << 4) + ka) ^ (z + n) ^ ((z >> 5) + kb)));
     n -= DELTA;

diff --git a/tea.h b/tea.h
index c227ec5..38a8da1 100644 (file)
--- a/tea.h
+++ b/tea.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: tea.h,v 1.1 2000/07/15 13:44:31 mdw Exp $
+ * $Id: tea.h,v 1.2 2000/07/29 09:56:47 mdw Exp $
  *
  * The Tiny Encryption Algorithm
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: tea.h,v $
+ * Revision 1.2  2000/07/29 09:56:47  mdw
+ * Allow the number of rounds to be configured.  This isn't exported
+ * through the gcipher interface, but it may be useful anyway.
+ *
  * Revision 1.1  2000/07/15 13:44:31  mdw
  * New ciphers.
  *
@@ -69,6 +73,7 @@ extern const octet tea_keysz[];
 /*----- Data structures ---------------------------------------------------*/
 
 typedef struct tea_ctx {
+  unsigned r;
   uint32 ka, kb, kc, kd;
 } tea_ctx;
 

diff --git a/xtea.c b/xtea.c
index 1d65c4d..32702fe 100644 (file)
--- a/xtea.c
+++ b/xtea.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: xtea.c,v 1.1 2000/07/15 13:44:31 mdw Exp $
+ * $Id: xtea.c,v 1.2 2000/07/29 09:56:47 mdw Exp $
  *
  * The Extended Tiny Encryption Algorithm
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: xtea.c,v $
+ * Revision 1.2  2000/07/29 09:56:47  mdw
+ * Allow the number of rounds to be configured.  This isn't exported
+ * through the gcipher interface, but it may be useful anyway.
+ *
  * Revision 1.1  2000/07/15 13:44:31  mdw
  * New ciphers.
  *
@@ -76,8 +80,9 @@ void xtea_init(xtea_ctx *k, const void *buf, size_t sz)
     p = kb;
   }
 
-  k->k[0] = LOAD32(p +  0);   k->k[1] = LOAD32(p +  4);
-  k->k[2] = LOAD32(p +  8);   k->k[3] = LOAD32(p + 12);
+  k->k[0] = LOAD32(p +  0); k->k[1] = LOAD32(p +  4);
+  k->k[2] = LOAD32(p +  8); k->k[3] = LOAD32(p + 12);
+  k->r = 32;
 
   if (p == kb)
     BURN(kb);
@@ -102,7 +107,7 @@ void xtea_eblk(const xtea_ctx *k, const uint32 *s, uint32 *d)
   uint32 n = 0;
   unsigned i;
 
-  for (i = 0; i < 32; i++) {
+  for (i = 0; i < k->r; i++) {
     y = U32(y + ((((z << 4) ^ (z >> 5)) + z) ^ (n + k->k[n & 3])));
     n += DELTA;
     z = U32(z + ((((y << 4) ^ (y >> 5)) + y) ^ (n + k->k[(n >> 11) & 3])));
@@ -113,10 +118,10 @@ void xtea_eblk(const xtea_ctx *k, const uint32 *s, uint32 *d)
 void xtea_dblk(const xtea_ctx *k, const uint32 *s, uint32 *d)
 {
   uint32 y = s[0], z = s[1];
-  uint32 n = DELTA << 5;
+  uint32 n = DELTA * k->r;
   unsigned i;
 
-  for (i = 0; i < 32; i++) {
+  for (i = 0; i < k->r; i++) {
     z = U32(z - ((((y << 4) ^ (y >> 5)) + y) ^ (n + k->k[(n >> 11) & 3])));
     n -= DELTA;
     y = U32(y - ((((z << 4) ^ (z >> 5)) + z) ^ (n + k->k[n & 3])));

diff --git a/xtea.h b/xtea.h
index 94f8d2c..af6c3a0 100644 (file)
--- a/xtea.h
+++ b/xtea.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: xtea.h,v 1.2 2000/07/15 13:47:14 mdw Exp $
+ * $Id: xtea.h,v 1.3 2000/07/29 09:56:47 mdw Exp $
  *
  * The Extended Tiny Encryption Algorithm
  *
@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: xtea.h,v $
+ * Revision 1.3  2000/07/29 09:56:47  mdw
+ * Allow the number of rounds to be configured.  This isn't exported
+ * through the gcipher interface, but it may be useful anyway.
+ *
  * Revision 1.2  2000/07/15 13:47:14  mdw
  * Whoops.  Fix the purpose comment.
  *
@@ -72,6 +76,7 @@ extern const octet xtea_keysz[];
 /*----- Data structures ---------------------------------------------------*/
 
 typedef struct xtea_ctx {
+  unsigned r;
   uint32 k[4];
 } xtea_ctx;