This file provides an API for the CCM authenticated encryption mode for block ciphers. More...

Data Structures
struct	mbedtls_ccm_context
	The CCM context-type definition. More...
Typedefs
typedef struct mbedtls_ccm_context	mbedtls_ccm_context
	The CCM context-type definition.
Functions
void	mbedtls_ccm_init (mbedtls_ccm_context *ctx)
	This function initializes the specified CCM context, to make references valid, and prepare the context for mbedtls_ccm_setkey() or mbedtls_ccm_free().
int	mbedtls_ccm_setkey (mbedtls_ccm_context ctx, mbedtls_cipher_id_t cipher, const unsigned char key, unsigned int keybits)
	This function initializes the CCM context set in the `ctx` parameter and sets the encryption key.
void	mbedtls_ccm_free (mbedtls_ccm_context *ctx)
	This function releases and clears the specified CCM context and underlying cipher sub-context.
int	mbedtls_ccm_encrypt_and_tag (mbedtls_ccm_context ctx, size_t length, const unsigned char iv, size_t iv_len, const unsigned char add, size_t add_len, const unsigned char input, unsigned char output, unsigned char tag, size_t tag_len)
	This function encrypts a buffer using CCM.
int	mbedtls_ccm_star_encrypt_and_tag (mbedtls_ccm_context ctx, size_t length, const unsigned char iv, size_t iv_len, const unsigned char add, size_t add_len, const unsigned char input, unsigned char output, unsigned char tag, size_t tag_len)
	This function encrypts a buffer using CCM*.
int	mbedtls_ccm_auth_decrypt (mbedtls_ccm_context ctx, size_t length, const unsigned char iv, size_t iv_len, const unsigned char add, size_t add_len, const unsigned char input, unsigned char output, const unsigned char tag, size_t tag_len)
	This function performs a CCM authenticated decryption of a buffer.
int	mbedtls_ccm_star_auth_decrypt (mbedtls_ccm_context ctx, size_t length, const unsigned char iv, size_t iv_len, const unsigned char add, size_t add_len, const unsigned char input, unsigned char output, const unsigned char tag, size_t tag_len)
	This function performs a CCM* authenticated decryption of a buffer.
int	mbedtls_ccm_self_test (int verbose)
	The CCM checkup routine.

Detailed Description

This file provides an API for the CCM authenticated encryption mode for block ciphers.

CCM combines Counter mode encryption with CBC-MAC authentication for 128-bit block ciphers.

Input to CCM includes the following elements:

Payload - data that is both authenticated and encrypted.
Associated data (Adata) - data that is authenticated but not encrypted, For example, a header.
Nonce - A unique value that is assigned to the payload and the associated data.

Definition of CCM: http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf RFC 3610 "Counter with CBC-MAC (CCM)"

Related: RFC 5116 "An Interface and Algorithms for Authenticated Encryption"

Definition of CCM*: IEEE 802.15.4 - IEEE Standard for Local and metropolitan area networks Integer representation is fixed most-significant-octet-first order and the representation of octets is most-significant-bit-first order. This is consistent with RFC 3610.

Definition in file ccm.h.

Typedef Documentation

typedef struct mbedtls_ccm_context mbedtls_ccm_context

The CCM context-type definition.

The CCM context is passed to the APIs called.

Function Documentation

int mbedtls_ccm_auth_decrypt	(	mbedtls_ccm_context *	ctx,
		size_t	length,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	add,
		size_t	add_len,
		const unsigned char *	input,
		unsigned char *	output,
		const unsigned char *	tag,
		size_t	tag_len
	)

This function performs a CCM authenticated decryption of a buffer.

Parameters:

ctx	The CCM context to use for decryption. This must be initialized and bound to a key.
length	The length of the input data in Bytes.
iv	The initialization vector (nonce). This must be a readable buffer of at least `iv_len` Bytes.
iv_len	The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, or 13. The length L of the message length field is 15 - `iv_len`.
add	The additional data field. This must be a readable buffer of at least that `add_len` Bytes..
add_len	The length of additional data in Bytes. This must be less than 2^16 - 2^8.
input	The buffer holding the input data. If `length` is greater than zero, `input` must be a readable buffer of at least that length.
output	The buffer holding the output data. If `length` is greater than zero, `output` must be a writable buffer of at least that length.
tag	The buffer holding the authentication field. This must be a readable buffer of at least `tag_len` Bytes.
tag_len	The length of the authentication field to generate in Bytes: 4, 6, 8, 10, 12, 14 or 16.

Returns:: 0 on success. This indicates that the message is authentic.; MBEDTLS_ERR_CCM_AUTH_FAILED if the tag does not match.; A cipher-specific error code on calculation failure.

Definition at line 132 of file ccm_alt.c.

int mbedtls_ccm_encrypt_and_tag	(	mbedtls_ccm_context *	ctx,
		size_t	length,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	add,
		size_t	add_len,
		const unsigned char *	input,
		unsigned char *	output,
		unsigned char *	tag,
		size_t	tag_len
	)

This function encrypts a buffer using CCM.

Note:: The tag is written to a separate buffer. To concatenate the tag with the output, as done in RFC-3610: Counter with CBC-MAC (CCM), use tag = output + length, and make sure that the output buffer is at least length + tag_len wide.

Parameters:

ctx	The CCM context to use for encryption. This must be initialized and bound to a key.
length	The length of the input data in Bytes.
iv	The initialization vector (nonce). This must be a readable buffer of at least `iv_len` Bytes.
iv_len	The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, or 13. The length L of the message length field is 15 - `iv_len`.
add	The additional data field. If `add_len` is greater than zero, `add` must be a readable buffer of at least that length.
add_len	The length of additional data in Bytes. This must be less than `2^16 - 2^8`.
input	The buffer holding the input data. If `length` is greater than zero, `input` must be a readable buffer of at least that length.
output	The buffer holding the output data. If `length` is greater than zero, `output` must be a writable buffer of at least that length.
tag	The buffer holding the authentication field. This must be a readable buffer of at least `tag_len` Bytes.
tag_len	The length of the authentication field to generate in Bytes: 4, 6, 8, 10, 12, 14 or 16.

Returns:: 0 on success.; A CCM or cipher-specific error code on failure.

Definition at line 76 of file ccm_alt.c.

void mbedtls_ccm_free ( mbedtls_ccm_context * ctx )

This function releases and clears the specified CCM context and underlying cipher sub-context.

Parameters:

ctx	The CCM context to clear. If this is `NULL`, the function has no effect. Otherwise, this must be initialized.

Definition at line 34 of file ccm_alt.c.

void mbedtls_ccm_init ( mbedtls_ccm_context * ctx )

This function initializes the specified CCM context, to make references valid, and prepare the context for mbedtls_ccm_setkey() or mbedtls_ccm_free().

Parameters:

ctx	The CCM context to initialize. This must not be `NULL`.

Definition at line 29 of file ccm_alt.c.

int mbedtls_ccm_self_test ( int verbose )

The CCM checkup routine.

Returns:: 0 on success.; 1 on failure.

Definition at line 471 of file ccm.c.

int mbedtls_ccm_setkey	(	mbedtls_ccm_context *	ctx,
		mbedtls_cipher_id_t	cipher,
		const unsigned char *	key,
		unsigned int	keybits
	)

This function initializes the CCM context set in the ctx parameter and sets the encryption key.

Parameters:

ctx	The CCM context to initialize. This must be an initialized context.
cipher	The 128-bit block cipher to use.
key	The encryption key. This must not be `NULL`.
keybits	The key size in bits. This must be acceptable by the cipher.

Returns:: 0 on success.; A CCM or cipher-specific error code on failure.

Definition at line 39 of file ccm_alt.c.

int mbedtls_ccm_star_auth_decrypt	(	mbedtls_ccm_context *	ctx,
		size_t	length,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	add,
		size_t	add_len,
		const unsigned char *	input,
		unsigned char *	output,
		const unsigned char *	tag,
		size_t	tag_len
	)

This function performs a CCM* authenticated decryption of a buffer.

Note:: When using this function in a variable tag length context, the tag length has to be decoded from iv and passed to this function as tag_len. (tag needs to be adjusted accordingly.)

Parameters:

ctx	The CCM context to use for decryption. This must be initialized and bound to a key.
length	The length of the input data in Bytes.
iv	The initialization vector (nonce). This must be a readable buffer of at least `iv_len` Bytes.
iv_len	The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, or 13. The length L of the message length field is 15 - `iv_len`.
add	The additional data field. This must be a readable buffer of at least that `add_len` Bytes.
add_len	The length of additional data in Bytes. This must be less than 2^16 - 2^8.
input	The buffer holding the input data. If `length` is greater than zero, `input` must be a readable buffer of at least that length.
output	The buffer holding the output data. If `length` is greater than zero, `output` must be a writable buffer of at least that length.
tag	The buffer holding the authentication field. This must be a readable buffer of at least `tag_len` Bytes.
tag_len	The length of the authentication field in Bytes. 0, 4, 6, 8, 10, 12, 14 or 16.

Warning:: Passing 0 as tag_len means that the message is nos longer authenticated.

Returns:: 0 on success.; MBEDTLS_ERR_CCM_AUTH_FAILED if the tag does not match.; A cipher-specific error code on calculation failure.

Definition at line 205 of file ccm_alt.c.

int mbedtls_ccm_star_encrypt_and_tag	(	mbedtls_ccm_context *	ctx,
		size_t	length,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	add,
		size_t	add_len,
		const unsigned char *	input,
		unsigned char *	output,
		unsigned char *	tag,
		size_t	tag_len
	)

This function encrypts a buffer using CCM*.

Note:: The tag is written to a separate buffer. To concatenate the tag with the output, as done in RFC-3610: Counter with CBC-MAC (CCM), use tag = output + length, and make sure that the output buffer is at least length + tag_len wide.; When using this function in a variable tag length context, the tag length has to be encoded into the iv passed to this function.

Parameters:

ctx	The CCM context to use for encryption. This must be initialized and bound to a key.
length	The length of the input data in Bytes.
iv	The initialization vector (nonce). This must be a readable buffer of at least `iv_len` Bytes.
iv_len	The length of the nonce in Bytes: 7, 8, 9, 10, 11, 12, or 13. The length L of the message length field is 15 - `iv_len`.
add	The additional data field. This must be a readable buffer of at least `add_len` Bytes.
add_len	The length of additional data in Bytes. This must be less than 2^16 - 2^8.
input	The buffer holding the input data. If `length` is greater than zero, `input` must be a readable buffer of at least that length.
output	The buffer holding the output data. If `length` is greater than zero, `output` must be a writable buffer of at least that length.
tag	The buffer holding the authentication field. This must be a readable buffer of at least `tag_len` Bytes.
tag_len	The length of the authentication field to generate in Bytes: 0, 4, 6, 8, 10, 12, 14 or 16.

Warning:: Passing 0 as tag_len means that the message is no longer authenticated.

Returns:: 0 on success.; A CCM or cipher-specific error code on failure.

Definition at line 195 of file ccm_alt.c.

Type:	Library
Created:	17 Dec 2019
Imports:	79
Forks:	0
Commits:	2
Dependents:	2
Dependencies:	0
Followers:	1

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