Generic cipher wrapper for mbed TLS. More...

Functions
const int *	mbedtls_cipher_list (void)
	This function retrieves the list of ciphers supported by the generic cipher module.
const mbedtls_cipher_info_t *	mbedtls_cipher_info_from_type (const mbedtls_cipher_type_t cipher_type)
	This function retrieves the cipher-information structure associated with the given cipher type.
const mbedtls_cipher_info_t *	mbedtls_cipher_info_from_string (const char *cipher_name)
	This function retrieves the cipher-information structure associated with the given cipher name.
const mbedtls_cipher_info_t *	mbedtls_cipher_info_from_values (const mbedtls_cipher_id_t cipher_id, int key_bitlen, const mbedtls_cipher_mode_t mode)
	This function retrieves the cipher-information structure associated with the given cipher ID, key size and mode.
void	mbedtls_cipher_init (mbedtls_cipher_context_t *ctx)
	This function initializes a `cipher_context` as NONE.
void	mbedtls_cipher_free (mbedtls_cipher_context_t *ctx)
	This function frees and clears the cipher-specific context of `ctx`.
int	mbedtls_cipher_setup (mbedtls_cipher_context_t ctx, const mbedtls_cipher_info_t cipher_info)
	This function initializes and fills the cipher-context structure with the appropriate values.
int	mbedtls_cipher_setkey (mbedtls_cipher_context_t ctx, const unsigned char key, int key_bitlen, const mbedtls_operation_t operation)
	This function sets the key to use with the given context.
int	mbedtls_cipher_set_iv (mbedtls_cipher_context_t ctx, const unsigned char iv, size_t iv_len)
	This function sets the initialization vector (IV) or nonce.
int	mbedtls_cipher_reset (mbedtls_cipher_context_t *ctx)
	This function resets the cipher state.
int	mbedtls_cipher_update_ad (mbedtls_cipher_context_t ctx, const unsigned char ad, size_t ad_len)
	This function adds additional data for AEAD ciphers.
int	mbedtls_cipher_update (mbedtls_cipher_context_t ctx, const unsigned char input, size_t ilen, unsigned char output, size_t olen)
	The generic cipher update function.
int	mbedtls_cipher_finish (mbedtls_cipher_context_t ctx, unsigned char output, size_t *olen)
	The generic cipher finalization function.
int	mbedtls_cipher_set_padding_mode (mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode)
	This function sets the padding mode, for cipher modes that use padding.
int	mbedtls_cipher_write_tag (mbedtls_cipher_context_t ctx, unsigned char tag, size_t tag_len)
	This function writes a tag for AEAD ciphers.
int	mbedtls_cipher_check_tag (mbedtls_cipher_context_t ctx, const unsigned char tag, size_t tag_len)
	This function checks the tag for AEAD ciphers.
int	mbedtls_cipher_crypt (mbedtls_cipher_context_t ctx, const unsigned char iv, size_t iv_len, const unsigned char input, size_t ilen, unsigned char output, size_t *olen)
	The generic all-in-one encryption/decryption function, for all ciphers except AEAD constructs.
int	mbedtls_cipher_auth_encrypt (mbedtls_cipher_context_t ctx, const unsigned char iv, size_t iv_len, const unsigned char ad, size_t ad_len, const unsigned char input, size_t ilen, unsigned char output, size_t olen, unsigned char *tag, size_t tag_len)
	The generic autenticated encryption (AEAD) function.
int	mbedtls_cipher_auth_decrypt (mbedtls_cipher_context_t ctx, const unsigned char iv, size_t iv_len, const unsigned char ad, size_t ad_len, const unsigned char input, size_t ilen, unsigned char output, size_t olen, const unsigned char *tag, size_t tag_len)
	The generic autenticated decryption (AEAD) function.

Detailed Description

Generic cipher wrapper for mbed TLS.

Author:: Adriaan de Jong <dejong@fox-it.com>

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

This file is part of mbed TLS (https://tls.mbed.org)

Definition in file cipher.c.

Function Documentation

int mbedtls_cipher_auth_decrypt	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	ad,
		size_t	ad_len,
		const unsigned char *	input,
		size_t	ilen,
		unsigned char *	output,
		size_t *	olen,
		const unsigned char *	tag,
		size_t	tag_len
	)

The generic autenticated decryption (AEAD) function.

Parameters:

ctx	The generic cipher context.
iv	The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
iv_len	The IV length for ciphers with variable-size IV. This parameter is discarded by ciphers with fixed-size IV.
ad	The additional data to be authenticated.
ad_len	The length of `ad`.
input	The buffer holding the input data.
ilen	The length of the input data.
output	The buffer for the output data. Must be able to hold at least `ilen`.
olen	The length of the output data, to be updated with the actual number of Bytes written.
tag	The buffer holding the authentication tag.
tag_len	The length of the authentication tag.

Returns:: 0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or MBEDTLS_ERR_CIPHER_AUTH_FAILED if data is not authentic, or a cipher-specific error code on failure for any other reason.

Note:: If the data is not authentic, then the output buffer is zeroed out to prevent the unauthentic plaintext being used, making this interface safer.

Definition at line 873 of file cipher.c.

int mbedtls_cipher_auth_encrypt	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	ad,
		size_t	ad_len,
		const unsigned char *	input,
		size_t	ilen,
		unsigned char *	output,
		size_t *	olen,
		unsigned char *	tag,
		size_t	tag_len
	)

The generic autenticated encryption (AEAD) function.

Parameters:

ctx	The generic cipher context.
iv	The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
iv_len	The IV length for ciphers with variable-size IV. This parameter is discarded by ciphers with fixed-size IV.
ad	The additional data to authenticate.
ad_len	The length of `ad`.
input	The buffer holding the input data.
ilen	The length of the input data.
output	The buffer for the output data. Must be able to hold at least `ilen`.
olen	The length of the output data, to be updated with the actual number of Bytes written.
tag	The buffer for the authentication tag.
tag_len	The desired length of the authentication tag.

Returns:: 0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or a cipher-specific error code.

Definition at line 841 of file cipher.c.

int mbedtls_cipher_check_tag	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	tag,
		size_t	tag_len
	)

This function checks the tag for AEAD ciphers.

Only supported with GCM. Must be called after mbedtls_cipher_finish().

Parameters:

ctx	The generic cipher context.
tag	The buffer holding the tag.
tag_len	The length of the tag to check.

Returns:: 0 on success, or a specific error code on failure.

Definition at line 769 of file cipher.c.

int mbedtls_cipher_crypt	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	iv,
		size_t	iv_len,
		const unsigned char *	input,
		size_t	ilen,
		unsigned char *	output,
		size_t *	olen
	)

The generic all-in-one encryption/decryption function, for all ciphers except AEAD constructs.

Parameters:

ctx	The generic cipher context.
iv	The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
iv_len	The IV length for ciphers with variable-size IV. This parameter is discarded by ciphers with fixed-size IV.
input	The buffer holding the input data.
ilen	The length of the input data.
output	The buffer for the output data. Must be able to hold at least `ilen` + block_size. Must not be the same buffer as input.
olen	The length of the output data, to be updated with the actual number of Bytes written.

Note:: Some ciphers do not use IVs nor nonce. For these ciphers, use iv = NULL and iv_len = 0.

Returns:: 0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption expected a full block but was not provided one, or MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting, or a cipher-specific error code on failure for any other reason.

Definition at line 812 of file cipher.c.

int mbedtls_cipher_finish	(	mbedtls_cipher_context_t *	ctx,
		unsigned char *	output,
		size_t *	olen
	)

The generic cipher finalization function.

If data still needs to be flushed from an incomplete block, the data contained in it is padded to the size of the last block, and written to the output buffer.

Parameters:

ctx	The generic cipher context.
output	The buffer to write data to. Needs block_size available.
olen	The length of the data written to the `output` buffer.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails, MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption expected a full block but was not provided one, MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting, or a cipher-specific error code on failure for any other reason.

Definition at line 626 of file cipher.c.

void mbedtls_cipher_free ( mbedtls_cipher_context_t * ctx )

This function frees and clears the cipher-specific context of ctx.

Freeing ctx itself remains the responsibility of the caller.

Definition at line 136 of file cipher.c.

const mbedtls_cipher_info_t* mbedtls_cipher_info_from_string ( const char * cipher_name )

This function retrieves the cipher-information structure associated with the given cipher name.

Parameters:

cipher_name Name of the cipher to search for.

Returns:: The cipher information structure associated with the given cipher_name, or NULL if not found.

Definition at line 102 of file cipher.c.

const mbedtls_cipher_info_t* mbedtls_cipher_info_from_type ( const mbedtls_cipher_type_t cipher_type )

This function retrieves the cipher-information structure associated with the given cipher type.

Parameters:

cipher_type Type of the cipher to search for.

Returns:: The cipher information structure associated with the given cipher_type, or NULL if not found.

Definition at line 91 of file cipher.c.

const mbedtls_cipher_info_t* mbedtls_cipher_info_from_values	(	const mbedtls_cipher_id_t	cipher_id,
		int	key_bitlen,
		const mbedtls_cipher_mode_t	mode
	)

This function retrieves the cipher-information structure associated with the given cipher ID, key size and mode.

Parameters:

cipher_id	The ID of the cipher to search for. For example, MBEDTLS_CIPHER_ID_AES.
key_bitlen	The length of the key in bits.
mode	The cipher mode. For example, MBEDTLS_MODE_CBC.

Returns:: The cipher information structure associated with the given cipher_id, or NULL if not found.

Definition at line 116 of file cipher.c.

void mbedtls_cipher_init ( mbedtls_cipher_context_t * ctx )

This function initializes a cipher_context as NONE.

Definition at line 131 of file cipher.c.

const int* mbedtls_cipher_list ( void )

This function retrieves the list of ciphers supported by the generic cipher module.

Returns:: A statically-allocated array of ciphers. The last entry is zero.

Definition at line 70 of file cipher.c.

int mbedtls_cipher_reset ( mbedtls_cipher_context_t * ctx )

This function resets the cipher state.

Parameters:

ctx	The generic cipher context.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails.

Definition at line 243 of file cipher.c.

int mbedtls_cipher_set_iv	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	iv,
		size_t	iv_len
	)

This function sets the initialization vector (IV) or nonce.

Parameters:

ctx	The generic cipher context.
iv	The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
iv_len	The IV length for ciphers with variable-size IV. This parameter is discarded by ciphers with fixed-size IV.

Returns:: 0 on success, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA

Note:: Some ciphers do not use IVs nor nonce. For these ciphers, this function has no effect.

Definition at line 214 of file cipher.c.

int mbedtls_cipher_set_padding_mode	(	mbedtls_cipher_context_t *	ctx,
		mbedtls_cipher_padding_t	mode
	)

This function sets the padding mode, for cipher modes that use padding.

The default passing mode is PKCS7 padding.

Parameters:

ctx	The generic cipher context.
mode	The padding mode.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE if the selected padding mode is not supported, or MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode does not support padding.

Definition at line 706 of file cipher.c.

int mbedtls_cipher_setkey	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	key,
		int	key_bitlen,
		const mbedtls_operation_t	operation
	)

This function sets the key to use with the given context.

Parameters:

ctx	The generic cipher context. May not be NULL. Must have been initialized using mbedtls_cipher_info_from_type() or mbedtls_cipher_info_from_string().
key	The key to use.
key_bitlen	The key length to use, in bits.
operation	The operation that the key will be used for: MBEDTLS_ENCRYPT or MBEDTLS_DECRYPT.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails, or a cipher-specific error code.

Definition at line 181 of file cipher.c.

int mbedtls_cipher_setup	(	mbedtls_cipher_context_t *	ctx,
		const mbedtls_cipher_info_t *	cipher_info
	)

This function initializes and fills the cipher-context structure with the appropriate values.

It also clears the structure.

Parameters:

ctx	The context to initialize. May not be NULL.
cipher_info	The cipher to use.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter failure, MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the cipher-specific context failed.

Definition at line 155 of file cipher.c.

int mbedtls_cipher_update	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	input,
		size_t	ilen,
		unsigned char *	output,
		size_t *	olen
	)

The generic cipher update function.

It encrypts or decrypts using the given cipher context. Writes as many block-sized blocks of data as possible to output. Any data that cannot be written immediately is either added to the next block, or flushed when mbedtls_cipher_finish() is called. Exception: For MBEDTLS_MODE_ECB, expects a single block in size. For example, 16 Bytes for AES.

Parameters:

ctx	The generic cipher context.
input	The buffer holding the input data.
ilen	The length of the input data.
output	The buffer for the output data. Must be able to hold at least `ilen` + block_size. Must not be the same buffer as input.
olen	The length of the output data, to be updated with the actual number of Bytes written.

Returns:: 0 on success, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails, MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an unsupported mode for a cipher, or a cipher-specific error code.

Note:: If the underlying cipher is GCM, all calls to this function, except the last one before mbedtls_cipher_finish(). Must have ilen as a multiple of the block_size.

Definition at line 270 of file cipher.c.

int mbedtls_cipher_update_ad	(	mbedtls_cipher_context_t *	ctx,
		const unsigned char *	ad,
		size_t	ad_len
	)

This function adds additional data for AEAD ciphers.

Only supported with GCM. Must be called exactly once, after mbedtls_cipher_reset().

Parameters:

ctx	The generic cipher context.
ad	The additional data to use.
ad_len	the Length of `ad`.

Returns:: 0 on success, or a specific error code on failure.

Definition at line 254 of file cipher.c.

int mbedtls_cipher_write_tag	(	mbedtls_cipher_context_t *	ctx,
		unsigned char *	tag,
		size_t	tag_len
	)

This function writes a tag for AEAD ciphers.

Only supported with GCM. Must be called after mbedtls_cipher_finish().

Parameters:

ctx	The generic cipher context.
tag	The buffer to write the tag to.
tag_len	The length of the tag to write.

Returns:: 0 on success, or a specific error code on failure.

Definition at line 754 of file cipher.c.

Type:	Program
Mbed OS support:	Mbed OS
Created:	29 Mar 2018
Imports:	22
Forks:	0
Commits:	5
Dependents:	0
Dependencies:	0
Followers:	6

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