chacha20poly1305 AEAD cipher

Provides RFC 8439 style chacha20poly1305. More...

Detailed Description

Provides RFC 8439 style chacha20poly1305.

This module provides the chacha20poly1305 AEAD symmetric cipher following rfc 8439.

Nonces must be unique per message for a single key. They are allowed to be predictable, e.g. a message counter and are allowed to be visible during transmission.

Files
file	chacha20poly1305.h
	Chacha20poly1305 functions.

Data Structures
union	chacha20poly1305_ctx_t
	Chacha20poly1305 state struct. More...

Macros
#define	CHACHA20POLY1305_KEY_BYTES   (32U)
	Key length in bytes.
#define	CHACHA20POLY1305_NONCE_BYTES   (12U)
	Nonce length in bytes.
#define	CHACHA20POLY1305_TAG_BYTES   (16U)
	Tag length in bytes.

Functions
void	chacha20poly1305_encrypt (uint8_t *cipher, const uint8_t *msg, size_t msglen, const uint8_t *aad, size_t aadlen, const uint8_t *key, const uint8_t *nonce)
	Encrypt a plaintext to ciphertext and append a tag to protect the ciphertext and additional data.
int	chacha20poly1305_decrypt (const uint8_t *cipher, size_t cipherlen, uint8_t *msg, size_t *msglen, const uint8_t *aad, size_t aadlen, const uint8_t *key, const uint8_t *nonce)
	Verify the tag and decrypt a ciphertext to plaintext.

Macro Definition Documentation

CHACHA20POLY1305_KEY_BYTES

#define CHACHA20POLY1305_KEY_BYTES   (32U)

Key length in bytes.

Definition at line 37 of file chacha20poly1305.h.

CHACHA20POLY1305_NONCE_BYTES

#define CHACHA20POLY1305_NONCE_BYTES   (12U)

Nonce length in bytes.

Definition at line 38 of file chacha20poly1305.h.

CHACHA20POLY1305_TAG_BYTES

#define CHACHA20POLY1305_TAG_BYTES   (16U)

Tag length in bytes.

Definition at line 39 of file chacha20poly1305.h.

Function Documentation

chacha20poly1305_decrypt()

int chacha20poly1305_decrypt	(	const uint8_t *	cipher,
		size_t	cipherlen,
		uint8_t *	msg,
		size_t *	msglen,
		const uint8_t *	aad,
		size_t	aadlen,
		const uint8_t *	key,
		const uint8_t *	nonce
	)

Verify the tag and decrypt a ciphertext to plaintext.

It is allowed to have cipher == msg

Parameters

[in]	cipher	resulting ciphertext, is CHACHA20POLY1305_TAG_BYTES longer than the message length
[in]	cipherlen	length of the ciphertext
[out]	msg	message to encrypt
[in]	msglen	resulting length in bytes of the message
[in]	aad	additional authenticated data to verify
[in]	aadlen	length of the additional authenticated data
[in]	key	key to decrypt with, must be CHACHA20POLY1305_KEY_BYTES long
[in]	nonce	Nonce to use. Must be CHACHA20POLY1305_NONCE_BYTES long

chacha20poly1305_encrypt()

void chacha20poly1305_encrypt	(	uint8_t *	cipher,
		const uint8_t *	msg,
		size_t	msglen,
		const uint8_t *	aad,
		size_t	aadlen,
		const uint8_t *	key,
		const uint8_t *	nonce
	)

Encrypt a plaintext to ciphertext and append a tag to protect the ciphertext and additional data.

It is allowed to have cipher == msg as long as there is CHACHA20POLY1305_TAG_BYTES space left to hold the authentication tag

Parameters

[out]	cipher	resulting ciphertext, is CHACHA20POLY1305_TAG_BYTES longer than the message length
[in]	msg	message to encrypt
[in]	msglen	length in bytes of the message
[in]	aad	additional authenticated data to protect
[in]	aadlen	length of the additional authenticated data
[in]	key	key to encrypt with, must be CHACHA20POLY1305_KEY_BYTES long
[in]	nonce	Nonce to use. Must be CHACHA20POLY1305_NONCE_BYTES long