CCM*: Add public API

Interface for CCM* (described in IEEE Std 802.15.4.).

include/mbedtls/ccm.h

@@ -102,7 +102,6 @@ void mbedtls_ccm_free( mbedtls_ccm_context *ctx );
 /**
  * \brief           This function encrypts a buffer using CCM.
  *
- *
  * \note            The tag is written to a separate buffer. To concatenate
  *                  the \p tag with the \p output, as done in <em>RFC-3610:
  *                  Counter with CBC-MAC (CCM)</em>, use
@@ -132,6 +131,45 @@ int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
                          const unsigned char *input, unsigned char *output,
                          unsigned char *tag, size_t tag_len );
 
+/**
+ * \brief           This function encrypts a buffer using CCM*.
+ *
+ * \note            The tag is written to a separate buffer. To concatenate
+ *                  the \p tag with the \p output, as done in <em>RFC-3610:
+ *                  Counter with CBC-MAC (CCM)</em>, use
+ *                  \p tag = \p output + \p length, and make sure that the
+ *                  output buffer is at least \p length + \p tag_len wide.
+ *
+ * \note            When using this function in a variable tag length context,
+ *                  the tag length has to be encoded into the \p iv passed to
+ *                  this function.
+ *
+ * \param ctx       The CCM context to use for encryption.
+ * \param length    The length of the input data in Bytes.
+ * \param iv        Initialization vector (nonce).
+ * \param iv_len    The length of the IV in Bytes: 7, 8, 9, 10, 11, 12, or 13.
+ * \param add       The additional data field.
+ * \param add_len   The length of additional data in Bytes.
+ *                  Must be less than 2^16 - 2^8.
+ * \param input     The buffer holding the input data.
+ * \param output    The buffer holding the output data.
+ *                  Must be at least \p length Bytes wide.
+ * \param tag       The buffer holding the tag.
+ * \param tag_len   The length of the tag to generate in Bytes:
+ *                  0, 4, 6, 8, 10, 12, 14 or 16.
+ *
+ * \warning         Passing 0 as \p tag_len means that the message is no
+ *                  longer authenticated.
+ *
+ * \return          \c 0 on success.
+ * \return          A CCM or cipher-specific error code on failure.
+ */
+int mbedtls_ccm_star_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
+                         const unsigned char *iv, size_t iv_len,
+                         const unsigned char *add, size_t add_len,
+                         const unsigned char *input, unsigned char *output,
+                         unsigned char *tag, size_t tag_len );
+
 /**
  * \brief           This function performs a CCM authenticated decryption of a
  *                  buffer.
@@ -160,6 +198,42 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len );
 
+/**
+ * \brief           This function performs a CCM* authenticated decryption of a
+ *                  buffer.
+ *
+ * \note            When using this function in a variable tag length context,
+ *                  the tag length has to be decoded from \p iv and passed to
+ *                  this function as \p tag_len. (\p tag needs to be adjusted
+ *                  accordingly.)
+ *
+ * \param ctx       The CCM context to use for decryption.
+ * \param length    The length of the input data in Bytes.
+ * \param iv        Initialization vector.
+ * \param iv_len    The length of the IV in Bytes: 7, 8, 9, 10, 11, 12, or 13.
+ * \param add       The additional data field.
+ * \param add_len   The length of additional data in Bytes.
+ *                  Must be less than 2^16 - 2^8.
+ * \param input     The buffer holding the input data.
+ * \param output    The buffer holding the output data.
+ *                  Must be at least \p length Bytes wide.
+ * \param tag       The buffer holding the tag.
+ * \param tag_len   The length of the tag in Bytes.
+ *                  0, 4, 6, 8, 10, 12, 14 or 16.
+ *
+ * \warning         Passing 0 as \p tag_len means that the message is no
+ *                  longer authenticated.
+ *
+ * \return          \c 0 on success. This indicates that the message is
+ *                  authentic.
+ * \return          #MBEDTLS_ERR_CCM_AUTH_FAILED if the tag does not match.
+ * \return          A cipher-specific error code on calculation failure.
+ */
+int mbedtls_ccm_star_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
+                      const unsigned char *iv, size_t iv_len,
+                      const unsigned char *add, size_t add_len,
+                      const unsigned char *input, unsigned char *output,
+                      const unsigned char *tag, size_t tag_len );
 
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /**