lotus-locus.h File Reference

LOTUS-AEAD and LOCUS-AEAD authenticated encryption algorithms. More...

#include "aead-common.h"

Go to the source code of this file.

Macros
#define	LOTUS_AEAD_KEY_SIZE   16
	Size of the key for LOTUS-AEAD.
#define	LOTUS_AEAD_TAG_SIZE   8
	Size of the authentication tag for LOTUS-AEAD.
#define	LOTUS_AEAD_NONCE_SIZE   16
	Size of the nonce for LOTUS-AEAD.
#define	LOCUS_AEAD_KEY_SIZE   16
	Size of the key for LOCUS-AEAD.
#define	LOCUS_AEAD_TAG_SIZE   8
	Size of the authentication tag for LOCUS-AEAD.
#define	LOCUS_AEAD_NONCE_SIZE   16
	Size of the nonce for LOCUS-AEAD.

Functions
int	lotus_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 LOTUS-AEAD. More...
int	lotus_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 LOTUS-AEAD. More...
int	locus_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 LOCUS-AEAD. More...
int	locus_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 LOCUS-AEAD. More...

Variables
aead_cipher_t const	lotus_aead_cipher
	Meta-information block for the LOTUS-AEAD cipher.
aead_cipher_t const	locus_aead_cipher
	Meta-information block for the LOCUS-AEAD cipher.

Detailed Description

LOTUS-AEAD and LOCUS-AEAD authenticated encryption algorithms.

LOTUS-AEAD and LOCUS-AEAD are authenticated encryption algorithms that are based around a tweakable variant of the GIFT-64 block cipher called TweGIFT-64. Both AEAD algorithms have a 128-bit key, a 128-bit nonce, and a 64-bit tag.

The two algorithms have the same key initialization, associated data processing, and tag generation mechanisms. They differ in how the input is encrypted with TweGIFT-64.

LOTUS-AEAD uses a method similar to the block cipher mode OTR. TweGIFT-64 is essentially converted into a 128-bit block cipher using a Feistel construction and four TweGIFT-64 block operations every 16 bytes of input.

LOCUS-AEAD uses a method similar to the block cipher mode OCB with two TweGIFT-64 block operations for every 8 bytes of input. LOCUS-AEAD requires both the block encrypt and block decrypt operations of TweGIFT-64, which increases the overall code size. LOTUS-AEAD only needs the block encrypt operation.

LOTUS-AEAD is the primary member of the family.

References: https://www.isical.ac.in/~lightweight/lotus/

Function Documentation

int locus_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 LOCUS-AEAD.

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 9 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

locus_aead_encrypt()

int locus_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 LOCUS-AEAD.

Parameters

c	Buffer to receive the output.
clen	On exit, set to the length of the output which includes the ciphertext and the 8 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

locus_aead_decrypt()

int lotus_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 LOTUS-AEAD.

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 9 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

lotus_aead_encrypt()

int lotus_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 LOTUS-AEAD.

Parameters

c	Buffer to receive the output.
clen	On exit, set to the length of the output which includes the ciphertext and the 8 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

lotus_aead_decrypt()