ccm.h File Reference

Counter with CBC-MAC mode of operation for block ciphers. More...

Detailed Description

Counter with CBC-MAC mode of operation for block ciphers.

Author

Freie Universitaet Berlin, Computer Systems & Telematics

Nico von Geyso nico..nosp@m.geys.nosp@m.o@fu-.nosp@m.berl.nosp@m.in.de

Definition in file ccm.h.

#include "crypto/ciphers.h"

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Macros
#define	CCM_BLOCK_SIZE   16
	Block size required for the cipher. More...
#define	CCM_MAC_MAX_LEN   16
	Maximum length for the appended MAC.

Functions
int	cipher_encrypt_ccm (const cipher_t *cipher, const uint8_t *auth_data, uint32_t auth_data_len, uint8_t mac_length, uint8_t length_encoding, const uint8_t *nonce, size_t nonce_len, const uint8_t *input, size_t input_len, uint8_t *output)
	Encrypt and authenticate data of arbitrary length in ccm mode. More...
int	cipher_decrypt_ccm (const cipher_t *cipher, const uint8_t *auth_data, uint32_t auth_data_len, uint8_t mac_length, uint8_t length_encoding, const uint8_t *nonce, size_t nonce_len, const uint8_t *input, size_t input_len, uint8_t *output)
	Decrypt data of arbitrary length in ccm mode. More...

CCM error codes
#define	CCM_ERR_INVALID_NONCE_LENGTH   (-2)
#define	CCM_ERR_INVALID_CBC_MAC   (-3)
#define	CCM_ERR_INVALID_DATA_LENGTH   (-3)
#define	CCM_ERR_INVALID_LENGTH_ENCODING   (-4)
#define	CCM_ERR_INVALID_MAC_LENGTH   (-5)

Macro Definition Documentation

CCM_BLOCK_SIZE

#define CCM_BLOCK_SIZE   16

Block size required for the cipher.

CCM is only defined for 128 bit ciphers.

Definition at line 42 of file ccm.h.

Function Documentation

cipher_decrypt_ccm()

int cipher_decrypt_ccm	(	const cipher_t *	cipher,
		const uint8_t *	auth_data,
		uint32_t	auth_data_len,
		uint8_t	mac_length,
		uint8_t	length_encoding,
		const uint8_t *	nonce,
		size_t	nonce_len,
		const uint8_t *	input,
		size_t	input_len,
		uint8_t *	output
	)

Decrypt data of arbitrary length in ccm mode.

Parameters

cipher	Already initialized cipher struct
auth_data	Additional data to authenticate in MAC
auth_data_len	Length of additional data, max (2^16 - 2^8)
mac_length	length of the appended MAC (between 4 and 16 - only even values)
length_encoding	maximal supported length of plaintext (2^(8*length_enc)).
nonce	Nounce for ctr mode encryption
nonce_len	Length of the nonce in octets (maximum: 15-length_encoding)
input	pointer to input data to decrypt
input_len	length of the input data, [0, 2^32]
output	pointer to allocated memory for decrypted data. It has to be of size data_len - mac_length.

Returns

Length of the decrypted data on a successful decryption, can be 0 if only auth_data and MAC is present.

A negative error code if something went wrong

cipher_encrypt_ccm()

int cipher_encrypt_ccm	(	const cipher_t *	cipher,
		const uint8_t *	auth_data,
		uint32_t	auth_data_len,
		uint8_t	mac_length,
		uint8_t	length_encoding,
		const uint8_t *	nonce,
		size_t	nonce_len,
		const uint8_t *	input,
		size_t	input_len,
		uint8_t *	output
	)

Encrypt and authenticate data of arbitrary length in ccm mode.

Parameters

cipher	Already initialized cipher struct
auth_data	Additional data to authenticate in MAC
auth_data_len	Length of additional data, max (2^16 - 2^8)
mac_length	length of the appended MAC (between 4 and 16 - only even values)
length_encoding	maximal supported length of plaintext (2^(8*length_enc)).
nonce	Nounce for ctr mode encryption
nonce_len	Length of the nonce in octets (maximum: 15-length_encoding)
input	pointer to input data to encrypt
input_len	length of the input data, [0, 2^32]
output	pointer to allocated memory for encrypted data. It has to be of size data_len + mac_length.

Returns

Length of encrypted data on a successful encryption, can be 0 if input_len=0 (no plaintext)

A negative error code if something went wrong