1 files changed, 88 insertions, 0 deletions
diff --git a/libtomcrypt/src/encauth/ccm/ccm_process.c b/libtomcrypt/src/encauth/ccm/ccm_process.c
new file mode 100644
index 0000000..8346d22
--- /dev/null
+++ b/libtomcrypt/src/encauth/ccm/ccm_process.c
@@ -0,0 +1,88 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+#include "tomcrypt.h"
+
+#ifdef LTC_CCM_MODE
+
+/**
+  Process plaintext/ciphertext through CCM
+  @param ccm       The CCM state
+  @param pt        The plaintext
+  @param ptlen     The plaintext length (ciphertext length is the same)
+  @param ct        The ciphertext
+  @param direction Encrypt or Decrypt mode (CCM_ENCRYPT or CCM_DECRYPT)
+  @return CRYPT_OK on success
+ */
+int ccm_process(ccm_state *ccm,
+                unsigned char *pt,     unsigned long ptlen,
+                unsigned char *ct,
+                int direction)
+{
+   unsigned char z, b;
+   unsigned long y;
+   int err;
+
+   LTC_ARGCHK(ccm != NULL);
+
+   /* Check aad has been correctly added */
+   if (ccm->aadlen != ccm->current_aadlen) {
+      return CRYPT_ERROR;
+   }
+
+   /* Check we do not process too much data */
+   if (ccm->ptlen < ccm->current_ptlen + ptlen) {
+      return CRYPT_ERROR;
+   }
+   ccm->current_ptlen += ptlen;
+
+   /* now handle the PT */
+   if (ptlen > 0) {
+      LTC_ARGCHK(pt != NULL);
+      LTC_ARGCHK(ct != NULL);
+
+      for (y = 0; y < ptlen; y++) {
+         /* increment the ctr? */
+         if (ccm->CTRlen == 16) {
+            for (z = 15; z > 15-ccm->L; z--) {
+               ccm->ctr[z] = (ccm->ctr[z] + 1) & 255;
+               if (ccm->ctr[z]) break;
+            }
+            if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->ctr, ccm->CTRPAD, &ccm->K)) != CRYPT_OK) {
+               return err;
+            }
+            ccm->CTRlen = 0;
+         }
+
+         /* if we encrypt we add the bytes to the MAC first */
+         if (direction == CCM_ENCRYPT) {
+            b     = pt[y];
+            ct[y] = b ^ ccm->CTRPAD[ccm->CTRlen++];
+         } else {
+            b     = ct[y] ^ ccm->CTRPAD[ccm->CTRlen++];
+            pt[y] = b;
+         }
+
+         if (ccm->x == 16) {
+            if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
+               return err;
+            }
+            ccm->x = 0;
+         }
+         ccm->PAD[ccm->x++] ^= b;
+      }
+   }
+
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */