xoodyak.h File Reference

Xoodyak authenticated encryption algorithm. More...

#include "aead-common.h"

Go to the source code of this file.

Data Structures
union	xoodyak_hash_state_t
	State information for Xoodyak incremental hashing modes. More...

Macros
#define	XOODYAK_KEY_SIZE   16
	Size of the key for Xoodyak.
#define	XOODYAK_TAG_SIZE   16
	Size of the authentication tag for Xoodyak.
#define	XOODYAK_NONCE_SIZE   16
	Size of the nonce for Xoodyak.
#define	XOODYAK_HASH_SIZE   32
	Size of the hash output for Xoodyak.

Functions
int	xoodyak_aead_encrypt (unsigned char *c, unsigned long long *clen, const unsigned char *m, unsigned long long mlen, const unsigned char *ad, unsigned long long adlen, const unsigned char *nsec, const unsigned char *npub, const unsigned char *k)
	Encrypts and authenticates a packet with Xoodyak. More...
int	xoodyak_aead_decrypt (unsigned char *m, unsigned long long *mlen, unsigned char *nsec, const unsigned char *c, unsigned long long clen, const unsigned char *ad, unsigned long long adlen, const unsigned char *npub, const unsigned char *k)
	Decrypts and authenticates a packet with Xoodyak. More...
int	xoodyak_hash (unsigned char *out, const unsigned char *in, unsigned long long inlen)
	Hashes a block of input data with Xoodyak to generate a hash value. More...
void	xoodyak_hash_init (xoodyak_hash_state_t *state)
	Initializes the state for a Xoodyak hashing operation. More...
void	xoodyak_hash_absorb (xoodyak_hash_state_t *state, const unsigned char *in, unsigned long long inlen)
	Aborbs more input data into a Xoodyak hashing state. More...
void	xoodyak_hash_squeeze (xoodyak_hash_state_t *state, unsigned char *out, unsigned long long outlen)
	Squeezes output data from a Xoodyak hashing state. More...
void	xoodyak_hash_finalize (xoodyak_hash_state_t *state, unsigned char *out)
	Returns the final hash value from a Xoodyak hashing operation. More...

Variables
aead_cipher_t const	xoodyak_cipher
	Meta-information block for the Xoodyak cipher.
aead_hash_algorithm_t const	xoodyak_hash_algorithm
	Meta-information block for the Xoodyak hash algorithm.

Detailed Description

Xoodyak authenticated encryption algorithm.

Xoodyak is an authenticated encryption and hash algorithm pair based around the 384-bit Xoodoo permutation that is similar in structure to Keccak but is more efficient than Keccak on 32-bit embedded devices. The Cyclist mode of operation is used to convert the permutation into a sponge for the higher-level algorithms.

The Xoodyak encryption mode has a 128-bit key, a 128-bit nonce, and a 128-bit authentication tag. The Xoodyak hashing mode has a 256-bit fixed hash output and can also be used as an extensible output function (XOF).

The Xoodyak specification describes a re-keying mechanism where the key for one packet is used to derive the key to use on the next packet. This provides some resistance against side channel attacks by making the session key a moving target. This library does not currently implement re-keying.

References: https://keccak.team/xoodyak.html

Function Documentation

int xoodyak_aead_decrypt	(	unsigned char *	m,
		unsigned long long *	mlen,
		unsigned char *	nsec,
		const unsigned char *	c,
		unsigned long long	clen,
		const unsigned char *	ad,
		unsigned long long	adlen,
		const unsigned char *	npub,
		const unsigned char *	k
	)

Decrypts and authenticates a packet with Xoodyak.

Parameters

m	Buffer to receive the plaintext message on output.
mlen	Receives the length of the plaintext message on output.
nsec	Secret nonce - not used by this algorithm.
c	Buffer that contains the ciphertext and authentication tag to decrypt.
clen	Length of the input data in bytes, which includes the ciphertext and the 16 byte authentication tag.
ad	Buffer that contains associated data to authenticate along with the packet but which does not need to be encrypted.
adlen	Length of the associated data in bytes.
npub	Points to the public nonce for the packet which must be 16 bytes in length.
k	Points to the 16 bytes of the key to use to decrypt the packet.

Returns

0 on success, -1 if the authentication tag was incorrect, or some other negative number if there was an error in the parameters.

See Also

xoodyak_aead_encrypt()

int xoodyak_aead_encrypt	(	unsigned char *	c,
		unsigned long long *	clen,
		const unsigned char *	m,
		unsigned long long	mlen,
		const unsigned char *	ad,
		unsigned long long	adlen,
		const unsigned char *	nsec,
		const unsigned char *	npub,
		const unsigned char *	k
	)

Encrypts and authenticates a packet with Xoodyak.

Parameters

c	Buffer to receive the output.
clen	On exit, set to the length of the output which includes the ciphertext and the 16 byte authentication tag.
m	Buffer that contains the plaintext message to encrypt.
mlen	Length of the plaintext message in bytes.
ad	Buffer that contains associated data to authenticate along with the packet but which does not need to be encrypted.
adlen	Length of the associated data in bytes.
nsec	Secret nonce - not used by this algorithm.
npub	Points to the public nonce for the packet which must be 16 bytes in length.
k	Points to the 16 bytes of the key to use to encrypt the packet.

Returns

0 on success, or a negative value if there was an error in the parameters.

See Also

xoodyak_aead_decrypt()

int xoodyak_hash	(	unsigned char *	out,
		const unsigned char *	in,
		unsigned long long	inlen
	)

Hashes a block of input data with Xoodyak to generate a hash value.

Parameters

out	Buffer to receive the hash output which must be at least XOODYAK_HASH_SIZE bytes in length.
in	Points to the input data to be hashed.
inlen	Length of the input data in bytes.

Returns

Returns zero on success or -1 if there was an error in the parameters.

void xoodyak_hash_absorb	(	xoodyak_hash_state_t *	state,
		const unsigned char *	in,
		unsigned long long	inlen
	)

Aborbs more input data into a Xoodyak hashing state.

Parameters

state	Hash state to be updated.
in	Points to the input data to be absorbed into the state.
inlen	Length of the input data to be absorbed into the state.

See Also

xoodyak_hash_init(), xoodyak_hash_squeeze()

void xoodyak_hash_finalize	(	xoodyak_hash_state_t *	state,
		unsigned char *	out
	)

Returns the final hash value from a Xoodyak hashing operation.

Parameters

state	Hash state to be finalized.
out	Points to the output buffer to receive the hash value.

Note

This is a wrapper around xoodyak_hash_squeeze() for a fixed length of XOODYAK_HASH_SIZE bytes.

See Also

xoodyak_hash_init(), xoodyak_hash_absorb()

void xoodyak_hash_init

(

xoodyak_hash_state_t *

state

)

Initializes the state for a Xoodyak hashing operation.

Parameters

state

Hash state to be initialized.

See Also

xoodyak_hash_absorb(), xoodyak_hash_squeeze(), xoodyak_hash()

void xoodyak_hash_squeeze	(	xoodyak_hash_state_t *	state,
		unsigned char *	out,
		unsigned long long	outlen
	)

Squeezes output data from a Xoodyak hashing state.

Parameters

state	Hash state to squeeze the output data from.
out	Points to the output buffer to receive the squeezed data.
outlen	Number of bytes of data to squeeze out of the state.

See Also

xoodyak_hash_init(), xoodyak_hash_absorb()