ocrypto_chacha20_poly1305_decrypt()

int ocrypto_chacha20_poly1305_decrypt	(	const uint8_t	tag[(16)],
		uint8_t *	m,
		const uint8_t *	c,
		size_t	c_len,
		const uint8_t *	a,
		size_t	a_len,
		const uint8_t *	n,
		size_t	n_len,
		const uint8_t	k[(32)]
	)

#include <crypto/nrf_oberon/include/ocrypto_chacha20_poly1305.h>

AEAD ChaCha20-Poly1305 decrypt.

If the authentication tag tag is valid for the ciphertext c, the additional authenticated data a, the encryption key k and the nonce n, the ciphertext is decrypted and put into m. The decrypted message m has the same length c_len as the original ciphertext.

Parameters

	tag	Received authentication tag.
[out]	m	Decoded message. Same length as received ciphertext.
	c	Received ciphertext.
	c_len	Length of c and m.
	a	Received additional authenticated data.
	a_len	Length of a. May be 0.
	n	Nonce.
	n_len	Length of n. 0 <= n_len <= ocrypto_chacha20_poly1305_NONCE_BYTES_MAX.
	k	Encryption key.

Return values

0	If tag is valid.
-1	Otherwise.

Remarks

m may be same as c.