Fixed partial encryption in CTR mode. Does not affect interop

[silc.git] / lib / silccrypt / aes.c

diff --git a/lib/silccrypt/aes.c b/lib/silccrypt/aes.c
index 9c5a2f196ee5d93ed7e9c893ea912c8a5e4a7268..f41a61d66766ae4cfb547721a75acea0d82ad5dc 100644 (file)
--- a/lib/silccrypt/aes.c
+++ b/lib/silccrypt/aes.c
@@ -190,13 +190,7 @@ SILC_CIPHER_API_CONTEXT_LEN(aes_ctr)
 SILC_CIPHER_API_ENCRYPT(aes_ctr)
 {
   AesContext *aes = context;
-  SilcUInt32 ctr[4];
-  int i;
-
-  SILC_GET32_MSB(ctr[0], iv);
-  SILC_GET32_MSB(ctr[1], iv + 4);
-  SILC_GET32_MSB(ctr[2], iv + 8);
-  SILC_GET32_MSB(ctr[3], iv + 12);
+  int i, k;
 
   i = aes->u.enc.inf.b[2];
   if (!i)
@@ -204,28 +198,17 @@ SILC_CIPHER_API_ENCRYPT(aes_ctr)
 
   while (len-- > 0) {
     if (i == 16) {
-      if (++ctr[3] == 0)
-       if (++ctr[2] == 0)
-         if (++ctr[1] == 0)
-           ++ctr[0];
-
-      SILC_PUT32_MSB(ctr[0], iv);
-      SILC_PUT32_MSB(ctr[1], iv + 4);
-      SILC_PUT32_MSB(ctr[2], iv + 8);
-      SILC_PUT32_MSB(ctr[3], iv + 12);
+      for (k = 15; k >= 0; k--)
+       if (++iv[k])
+         break;
 
-      aes_encrypt(iv, iv, &aes->u.enc);
+      aes_encrypt(iv, aes->u.enc.pad, &aes->u.enc);
       i = 0;
     }
-    *dst++ = *src++ ^ iv[i++];
+    *dst++ = *src++ ^ aes->u.enc.pad[i++];
   }
   aes->u.enc.inf.b[2] = i;
 
-  SILC_PUT32_MSB(ctr[0], iv);
-  SILC_PUT32_MSB(ctr[1], iv + 4);
-  SILC_PUT32_MSB(ctr[2], iv + 8);
-  SILC_PUT32_MSB(ctr[3], iv + 12);
-
   return TRUE;
 }