CAU3 CHACHA20_POLY1305 driver

Overview

This section describes the programming interface of the CAU3 CHACHA20_POLY1305 driver.

Functions
status_t	CAU3_CHACHA20_POLY1305_SetKey (CAU3_Type *base, cau3_handle_t *handle, const uint8_t *key, size_t keySize)
	Load 256-bit key into CAU3 key context (in key slot). More...
status_t	CAU3_CHACHA20_POLY1305_Encrypt (CAU3_Type *base, cau3_handle_t *handle, const uint8_t *plaintext, uint8_t *ciphertext, size_t size, const uint8_t *aad, size_t aadLen, const uint8_t *nonce, uint8_t *tag)
	Perform ChaCha-Poly encryption/authentication. More...
status_t	CAU3_CHACHA20_POLY1305_Decrypt (CAU3_Type *base, cau3_handle_t *handle, const uint8_t *ciphertext, uint8_t *plaintext, size_t size, const uint8_t *aad, size_t aadLen, const uint8_t *nonce, const uint8_t *tag)
	Perform ChaCha-Poly decryption/authentication check. More...

Function Documentation

status_t CAU3_CHACHA20_POLY1305_SetKey	(	CAU3_Type *	base,
		cau3_handle_t *	handle,
		const uint8_t *	key,
		size_t	keySize
	)

Load the key context into the private DMEM for CHACHA20_POLY1305 AEAD.

Parameters

base	CAU3 peripheral base address.
handle	Handle used for the request.
key	0-mod-4 aligned pointer to CHACHA20_POLY1305 256-bit key.
keySize	Size of the key in bytes. Shall be 32.

Returns

status from set key operation

status_t CAU3_CHACHA20_POLY1305_Encrypt	(	CAU3_Type *	base,
		cau3_handle_t *	handle,
		const uint8_t *	plaintext,
		uint8_t *	ciphertext,
		size_t	size,
		const uint8_t *	aad,
		size_t	aadLen,
		const uint8_t *	nonce,
		uint8_t *	tag
	)

Perform ChaCha encryption over a message of "n" bytes, and authentication over the encrypted data plus an additional authenticated data, returning encrypted data + a message digest.

Parameters

	base	CAU3 peripheral base address
	handle	Handle used for this request. The keySlot member specifies key context with key and IV.
	plaintext	The uint8_t source message to be encrypted, any alignment
[out]	ciphertext	is a pointer to the output encrypted message, any aligment
	size	The length of the plaintext and ciphertext in bytes
	aad	A pointer to the additional authenticated data, any alignment
	aadLen	Length of additional authenticated data in bytes
	nonce	0-mod-4 aligned pointer to CHACHA20_POLY1305 96-bit nonce.
[out]	tag	A pointer to the 128-bit message digest output, any alignment

Returns

status check from task completion

status_t CAU3_CHACHA20_POLY1305_Decrypt	(	CAU3_Type *	base,
		cau3_handle_t *	handle,
		const uint8_t *	ciphertext,
		uint8_t *	plaintext,
		size_t	size,
		const uint8_t *	aad,
		size_t	aadLen,
		const uint8_t *	nonce,
		const uint8_t *	tag
	)

Perform ChaCha decryption over a message of "n" bytes, and checks authentication over the encrypted data plus an additional authenticated data, returning decrypted data. IF the tag authentication fails, the task terminates with error and the output is forced to zero.

Parameters

	base	CAU3 peripheral base address
	handle	Handle used for this request. The keySlot member specifies key context with key and IV.
	ciphertext	The uint8_t source msg to be decrypted, any alignment
[out]	plaintext	A pointer to the output decrypted message, any alignment
	size	Length of the plaintext and ciphertext in bytes
	aad	A pointer to the additional authenticated data, any alignment
	aadLen	Length of additional authenticated data in bytes
	nonce	0-mod-4 aligned pointer to CHACHA20_POLY1305 96-bit nonce.
	tag	A pointer to the 128-bit msg digest input to be checked, any alignment

Returns

status check from task completion