CCM*: Add public API
Interface for CCM* (described in IEEE Std 802.15.4.).
diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index 5a34f3a..7d117d9 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -61,6 +61,55 @@
mbedtls_ccm_context;
/**
+ * \brief The CCM* callback for encrypting with variable tag length.
+ * The function pointer is passed to the APIs called. This
+ * function calculates the nonce and returns it in a buffer.
+ *
+ * \warning This function must not return the same nonce more than once
+ * in the lifetime of the key!
+ *
+ * \note To prevent attacks taking advantage of the variable tag
+ * length CCM* encodes the tag length in the nonce. The method
+ * of encoding may vary. Standards might mandate encoding other
+ * information in the nonce (e.g. address and frame counter)
+ * too.
+ *
+ * \param app_ctx A pointer to structure containing the application context
+ * if it is necessary for calculating the initialisation vector
+ * (nonce).
+ * \param tag_len Length of the tag in bytes.
+ * \nonce Output variable, points to the buffer capable of holding the
+ * calculated nonce. Must be at least \p nonce_len bytes long.
+ * \nonce_len The length of the nonce in bytes.
+ *
+ * \return \c 0 on success.
+ * \return MBEDTLS_ERR_CCM_BAD_INPUT error code on failure.
+ */
+typedef int (*mbedtls_ccm_star_get_nonce_t)( void *app_ctx, size_t tag_len,
+ unsigned char *nonce,
+ size_t nonce_len );
+
+/**
+ * \brief The CCM* callback for decrypting with variable tag length.
+ * The function pointer is passed to the APIs called. This
+ * function calculates and returns the length of the tag in the
+ * output parameter.
+ *
+ * \param app_ctx A pointer to structure containing the application context
+ * if it is necessary for decoding the tag length or validating
+ * the initialisation vector (nonce).
+ * \param tag_len Output variable for holding the tag length in bytes.
+ * \nonce A buffer containing the nonce.
+ * \nonce_len The length of the nonce in bytes.
+ *
+ * \return \c 0 on success.
+ * \return MBEDTLS_ERR_CCM_BAD_INPUT error code on failure.
+ */
+typedef int (*mbedtls_ccm_star_get_tag_len_t)( void *app_ctx, size_t* tag_len,
+ const unsigned char *nonce,
+ size_t nonce_len );
+
+/**
* \brief This function initializes the specified CCM context,
* to make references valid, and prepare the context
* for mbedtls_ccm_setkey() or mbedtls_ccm_free().
@@ -97,7 +146,6 @@
/**
* \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
@@ -128,6 +176,82 @@
unsigned char *tag, size_t tag_len );
/**
+ * \brief This function encrypts a buffer using CCM* with fixed tag
+ * length.
+ *
+ * \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.
+ *
+ * \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_sfix_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 encrypts a buffer using CCM* with variable
+ * tag length.
+ *
+ * \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.
+ *
+ * \param ctx The CCM context to use for encryption.
+ * \param length The length of the input data in Bytes.
+ * \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.
+ * \param get_iv A callback function returning the IV (nonce) with the
+ * tag length encoded in it.
+ * \param get_iv_ctx Context passed to the \p get_iv callback.
+ *
+ * \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_svar_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
+ 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, mbedtls_ccm_star_get_nonce_t get_iv,
+ void *get_iv_ctx );
+
+/**
* \brief This function performs a CCM authenticated decryption of a
* buffer.
*
@@ -155,6 +279,74 @@
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 with fixed tag length.
+ *
+ * \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_sfix_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 );
+
+/**
+ * \brief This function performs a CCM* authenticated decryption
+ * of a buffer with variable tag length.
+ *
+ * \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. Unlike the \p input
+ * parameters of other Mbed TLS CCM functions, this buffer
+ * holds the concatenation of the encrypted data and the
+ * authentication tag.
+ * \param output The buffer holding the output data.
+ * Must be at least \p length Bytes wide.
+ * \param output_len The length of the decrypted data.
+ * \param get_tag_len A callback function returning the tag length.
+ * \param get_tlen_ctx Context passed to the \p get_tag_len callback.
+ *
+ *
+ * \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_svar_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,
+ size_t* output_len,
+ mbedtls_ccm_star_get_tag_len_t get_tag_len,
+ void *get_tlen_ctx );
+
#ifdef __cplusplus
}
#endif