X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=libtomcrypt%2Fsrc%2Fencauth%2Fccm%2Fccm_init.c;fp=libtomcrypt%2Fsrc%2Fencauth%2Fccm%2Fccm_init.c;h=b24e33e418bb7e22cead3d182639cd85a9a9a6f2;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage

diff --git a/libtomcrypt/src/encauth/ccm/ccm_init.c b/libtomcrypt/src/encauth/ccm/ccm_init.c
new file mode 100644
index 0000000..b24e33e
--- /dev/null
+++ b/libtomcrypt/src/encauth/ccm/ccm_init.c
@@ -0,0 +1,81 @@
+/* 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
+
+/**
+  Initialize a CCM state
+  @param ccm     The CCM state to initialize
+  @param cipher  The index of the cipher to use
+  @param key     The secret key
+  @param keylen  The length of the secret key
+  @param ptlen   The length of the plain/cipher text that will be processed
+  @param taglen  The max length of the MAC tag
+  @param aadlen  The length of the AAD
+
+  @return CRYPT_OK on success
+ */
+int ccm_init(ccm_state *ccm, int cipher,
+             const unsigned char *key, int keylen, int ptlen, int taglen, int aadlen)
+{
+   int            err;
+
+   LTC_ARGCHK(ccm    != NULL);
+   LTC_ARGCHK(key    != NULL);
+   LTC_ARGCHK(taglen != 0);
+
+   XMEMSET(ccm, 0, sizeof(ccm_state));
+
+   /* check cipher input */
+   if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
+      return err;
+   }
+   if (cipher_descriptor[cipher].block_length != 16) {
+      return CRYPT_INVALID_CIPHER;
+   }
+
+   /* make sure the taglen is even and <= 16 */
+   ccm->taglen = taglen;
+   ccm->taglen &= ~1;
+   if (ccm->taglen > 16) {
+      ccm->taglen = 16;
+   }
+
+   /* can't use < 4 */
+   if (ccm->taglen < 4) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* schedule key */
+   if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, &ccm->K)) != CRYPT_OK) {
+      return err;
+   }
+   ccm->cipher = cipher;
+
+   /* let's get the L value */
+   ccm->ptlen = ptlen;
+   ccm->L   = 0;
+   while (ptlen) {
+      ++ccm->L;
+      ptlen >>= 8;
+   }
+   if (ccm->L <= 1) {
+      ccm->L = 2;
+   }
+
+   ccm->aadlen = aadlen;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */