mbedtls_md_init_ctx() function

The context to set up.

The information structure of the message-digest algorithm to use.

This function selects the message digest algorithm to use, and allocates internal structures. It should be called after mbedtls_md_init() or mbedtls_md_free(). Makes it necessary to call mbedtls_md_free() later.

This function initializes a message-digest context without binding it to a particular message-digest algorithm. This function should always be called first. It prepares the context for mbedtls_md_setup() for binding it to a message-digest algorithm.

This function clears the internal structure of \p ctx and frees any embedded internal structure, but does not free \p ctx itself. If you have called mbedtls_md_setup() on \p ctx, you must call mbedtls_md_free() when you are no longer using the context. Calling this function if you have previously called mbedtls_md_init() and nothing else is optional. You must not call this function if you have not called mbedtls_md_init().

This function sets the HMAC key and prepares to authenticate a new message. Call this function after mbedtls_md_setup(), to use the MD context for an HMAC calculation, then call mbedtls_md_hmac_update() to provide the input data, and mbedtls_md_hmac_finish() to get the HMAC value.

This function feeds an input buffer into an ongoing HMAC computation. Call mbedtls_md_hmac_starts() or mbedtls_md_hmac_reset() before calling this function. You may call this function multiple times to pass the input piecewise. Afterwards, call mbedtls_md_hmac_finish().

This function finishes the HMAC operation, and writes the result to the output buffer. Call this function after mbedtls_md_hmac_starts() and mbedtls_md_hmac_update() to get the HMAC value. Afterwards you may either call mbedtls_md_free() to clear the context, or call mbedtls_md_hmac_reset() to reuse the context with the same HMAC key.

This function feeds an input buffer into an ongoing message-digest computation. You must call mbedtls_md_starts() before calling this function. You may call this function multiple times. Afterwards, call mbedtls_md_finish().

This function prepares to authenticate a new message with the same key as the previous HMAC operation. You may call this function after mbedtls_md_hmac_finish(). Afterwards call mbedtls_md_hmac_update() to pass the new input.

This function starts a message-digest computation. You must call this function after setting up the context with mbedtls_md_setup(), and before passing data with mbedtls_md_update().

This function finishes the digest operation, and writes the result to the output buffer. Call this function after a call to mbedtls_md_starts(), followed by any number of calls to mbedtls_md_update(). Afterwards, you may either clear the context with mbedtls_md_free(), or call mbedtls_md_starts() to reuse the context for another digest operation with the same algorithm.

This function clones the state of an message-digest context. \warning This function clones the message-digest state, not the HMAC state.