comet.h File Reference

COMET authenticated encryption algorithm. More...

#include "aead-common.h"

Go to the source code of this file.

Macros
#define	COMET_KEY_SIZE   16
	Size of the key for all COMET family members.
#define	COMET_128_TAG_SIZE   16
	Size of the authentication tag for the 128-bit versions of COMET.
#define	COMET_64_TAG_SIZE   8
	Size of the authentication tag for the 64-bit versions of COMET.
#define	COMET_128_NONCE_SIZE   16
	Size of the nonce for the 128-bit versions of COMET.
#define	COMET_64_NONCE_SIZE   15
	Size of the nonce for the 64-bit versions of COMET.

Functions
int	comet_128_cham_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 COMET-128_CHAM-128/128. More...
int	comet_128_cham_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 COMET-128_CHAM-128/128. More...
int	comet_64_cham_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 COMET-64_CHAM-64/128. More...
int	comet_64_cham_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 COMET-64_CHAM-64/128. More...
int	comet_64_speck_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 COMET-64_SPECK-64/128. More...
int	comet_64_speck_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 COMET-64_SPECK-64/128. More...

Variables
aead_cipher_t const	comet_128_cham_cipher
	Meta-information block for the COMET-128_CHAM-128/128 cipher.
aead_cipher_t const	comet_64_cham_cipher
	Meta-information block for the COMET-64_CHAM-64/128 cipher.
aead_cipher_t const	comet_64_speck_cipher
	Meta-information block for the COMET-64_SPECK-64/128 cipher.

Detailed Description

COMET authenticated encryption algorithm.

COMET is a family of authenticated encryption algorithms that are built around an underlying block cipher. This library implements three members of the family:

• COMET-128_CHAM-128/128 which has a 128-bit key, a 128-bit nonce, and a 128-bit tag, built around the CHAM-128/128 block cipher.
• COMET-64_CHAM-64/128 which has a 128-bit key, a 120-bit nonce, and a 64-bit tag, built around the CHAM-64/128 block cipher.
• COMET-64_SPECK-64/128 which has a 128-bit key, a 120-bit nonce, and a 64-bit tag, built around the SPECK-64/128 block cipher.

There is also another family member that is built around AES but this library does not implement that version.

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

Function Documentation

int comet_128_cham_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 COMET-128_CHAM-128/128.

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

comet_128_cham_aead_encrypt()

int comet_128_cham_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 COMET-128_CHAM-128/128.

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

comet_128_cham_aead_decrypt()

int comet_64_cham_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 COMET-64_CHAM-64/128.

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 8 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 15 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

comet_64_cham_aead_encrypt()

int comet_64_cham_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 COMET-64_CHAM-64/128.

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 15 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

comet_64_cham_aead_decrypt()

int comet_64_speck_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 COMET-64_SPECK-64/128.

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 8 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 15 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

comet_64_speck_aead_encrypt()

int comet_64_speck_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 COMET-64_SPECK-64/128.

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 15 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

comet_64_speck_aead_decrypt()