romulus-m-aead.h File Reference

Romulus-M authenticated encryption algorithm. More...

#include <stddef.h>

Go to the source code of this file.

Macros
#define	ROMULUS_M_KEY_SIZE   16
	Size of the key for Romulus-M.
#define	ROMULUS_M_TAG_SIZE   16
	Size of the authentication tag for Romulus-M.
#define	ROMULUS_M_NONCE_SIZE   16
	Size of the nonce for Romulus-M.

Functions
int	romulus_m_aead_encrypt (unsigned char *c, size_t *clen, const unsigned char *m, size_t mlen, const unsigned char *ad, size_t adlen, const unsigned char *npub, const unsigned char *k)
	Encrypts and authenticates a packet with Romulus-M. More...
int	romulus_m_aead_decrypt (unsigned char *m, size_t *mlen, const unsigned char *c, size_t clen, const unsigned char *ad, size_t adlen, const unsigned char *npub, const unsigned char *k)
	Decrypts and authenticates a packet with Romulus-M. More...

Detailed Description

Romulus-M authenticated encryption algorithm.

Romulus is a family of authenticated encryption algorithms that are built around the SKINNY-128-384+ tweakable block cipher. This API implements the Romulus-N variant which has a 128-bit key, a 128-bit nonce, and a 128-bit tag.

The Romulus-M variant is resistant to nonce reuse as long as the combination of the associated data and plaintext is unique. If the same associated data and plaintext are reused under the same nonce, then the scheme will leak that the same plaintext has been sent for a second time but will not reveal the plaintext itself.

References: https://romulusae.github.io/romulus/

Function Documentation

int romulus_m_aead_decrypt	(	unsigned char *	m,
		size_t *	mlen,
		const unsigned char *	c,
		size_t	clen,
		const unsigned char *	ad,
		size_t	adlen,
		const unsigned char *	npub,
		const unsigned char *	k
	)

Decrypts and authenticates a packet with Romulus-M.

Parameters

m	Buffer to receive the plaintext message on output.
mlen	Receives the length of the plaintext message on output.
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

romulus_m_aead_encrypt()

int romulus_m_aead_encrypt	(	unsigned char *	c,
		size_t *	clen,
		const unsigned char *	m,
		size_t	mlen,
		const unsigned char *	ad,
		size_t	adlen,
		const unsigned char *	npub,
		const unsigned char *	k
	)

Encrypts and authenticates a packet with Romulus-M.

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.
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

romulus_m_aead_decrypt()