Generic cipher wrapper for mbed TLS. More...

Functions
const int *	cipher_list (void)
	Returns the list of ciphers supported by the generic cipher module.
const cipher_info_t *	cipher_info_from_type (const cipher_type_t cipher_type)
	Returns the cipher information structure associated with the given cipher type.
const cipher_info_t *	cipher_info_from_string (const char *cipher_name)
	Returns the cipher information structure associated with the given cipher name.
const cipher_info_t *	cipher_info_from_values (const cipher_id_t cipher_id, int key_length, const cipher_mode_t mode)
	Returns the cipher information structure associated with the given cipher id, key size and mode.
void	cipher_init (cipher_context_t *ctx)
	Initialize a cipher_context (as NONE)
void	cipher_free (cipher_context_t *ctx)
	Free and clear the cipher-specific context of ctx.
int	cipher_init_ctx (cipher_context_t ctx, const cipher_info_t cipher_info)
	Initialises and fills the cipher context structure with the appropriate values.
int	cipher_free_ctx (cipher_context_t *ctx)
	Free the cipher-specific context of ctx.
int	cipher_setkey (cipher_context_t ctx, const unsigned char key, int key_length, const operation_t operation)
	Set the key to use with the given context.
int	cipher_set_iv (cipher_context_t ctx, const unsigned char iv, size_t iv_len)
	Set the initialization vector (IV) or nonce.
int	cipher_reset (cipher_context_t *ctx)
	Finish preparation of the given context.
int	cipher_update_ad (cipher_context_t ctx, const unsigned char ad, size_t ad_len)
	Add additional data (for AEAD ciphers).
int	cipher_update (cipher_context_t ctx, const unsigned char input, size_t ilen, unsigned char output, size_t olen)
	Generic cipher update function.
int	cipher_finish (cipher_context_t ctx, unsigned char output, size_t *olen)
	Generic cipher finalisation function.
int	cipher_set_padding_mode (cipher_context_t *ctx, cipher_padding_t mode)
	Set padding mode, for cipher modes that use padding.
int	cipher_write_tag (cipher_context_t ctx, unsigned char tag, size_t tag_len)
	Write tag for AEAD ciphers.
int	cipher_check_tag (cipher_context_t ctx, const unsigned char tag, size_t tag_len)
	Check tag for AEAD ciphers.
int	cipher_crypt (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)
	Generic all-in-one encryption/decryption (for all ciphers except AEAD constructs).
int	cipher_auth_encrypt (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)
	Generic autenticated encryption (AEAD ciphers).
int	cipher_auth_decrypt (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)
	Generic autenticated decryption (AEAD ciphers).
int	cipher_self_test (int verbose)
	Checkup routine.

Detailed Description

Generic cipher wrapper for mbed TLS.

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

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

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Definition in file cipher.c.

Function Documentation

int cipher_auth_decrypt	(	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
	)

Generic autenticated decryption (AEAD ciphers).

Parameters:

ctx	generic cipher context
iv	IV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_len	IV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
ad	Additional data to be authenticated.
ad_len	Length of ad.
input	buffer holding the input data
ilen	length of the input data
output	buffer for the output data. Should be able to hold at least ilen.
olen	length of the output data, will be filled with the actual number of bytes written.
tag	buffer holding the authentication tag
tag_len	length of the authentication tag

Returns:: 0 on success, or POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or POLARSSL_ERR_CIPHER_AUTH_FAILED if data isn't authentic, or a cipher specific error code.

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

Definition at line 857 of file cipher.c.

int cipher_auth_encrypt	(	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
	)

Generic autenticated encryption (AEAD ciphers).

Parameters:

ctx	generic cipher context
iv	IV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_len	IV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
ad	Additional data to authenticate.
ad_len	Length of ad.
input	buffer holding the input data
ilen	length of the input data
output	buffer for the output data. Should be able to hold at least ilen.
olen	length of the output data, will be filled with the actual number of bytes written.
tag	buffer for the authentication tag
tag_len	desired tag length

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

Definition at line 825 of file cipher.c.

int cipher_check_tag	(	cipher_context_t *	ctx,
		const unsigned char *	tag,
		size_t	tag_len
	)

Check tag for AEAD ciphers.

Currently only supported with GCM. Must be called after cipher_finish().

Parameters:

ctx	Generic cipher context
tag	Buffer holding the tag
tag_len	Length of the tag to check

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

Definition at line 753 of file cipher.c.

int cipher_crypt	(	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
	)

Generic all-in-one encryption/decryption (for all ciphers except AEAD constructs).

Parameters:

ctx	generic cipher context
iv	IV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_len	IV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
input	buffer holding the input data
ilen	length of the input data
output	buffer for the output data. Should be able to hold at least ilen + block_size. Cannot be the same buffer as input!
olen	length of the output data, will be filled with the actual number of bytes written.

Note:: Some ciphers don't use IVs nor NONCE. For these ciphers, use iv = NULL and iv_len = 0.

Returns:: 0 on success, or POLARSSL_ERR_CIPHER_BAD_INPUT_DATA, or POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption expected a full block but was not provided one, or POLARSSL_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting, or a cipher specific error code.

Definition at line 796 of file cipher.c.

int cipher_finish	(	cipher_context_t *	ctx,
		unsigned char *	output,
		size_t *	olen
	)

Generic cipher finalisation function.

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

Parameters:

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

Returns:: 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails, POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption expected a full block but was not provided one, POLARSSL_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting or a cipher specific error code.

Definition at line 610 of file cipher.c.

void cipher_free ( cipher_context_t * ctx )

Free and clear the cipher-specific context of ctx.

Freeing ctx itself remains the responsibility of the caller.

Definition at line 131 of file cipher.c.

int cipher_free_ctx ( cipher_context_t * ctx )

Free the cipher-specific context of ctx.

Freeing ctx itself remains the responsibility of the caller.

Parameters:

ctx	Free the cipher-specific context

Returns:: 0

Definition at line 169 of file cipher.c.

const cipher_info_t* cipher_info_from_string ( const char * cipher_name )

Returns 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 97 of file cipher.c.

const cipher_info_t* cipher_info_from_type ( const cipher_type_t cipher_type )

Returns 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 86 of file cipher.c.

const cipher_info_t* cipher_info_from_values	(	const cipher_id_t	cipher_id,
		int	key_length,
		const cipher_mode_t	mode
	)

Returns the cipher information structure associated with the given cipher id, key size and mode.

Parameters:

cipher_id	Id of the cipher to search for (e.g. POLARSSL_CIPHER_ID_AES)
key_length	Length of the key in bits
mode	Cipher mode (e.g. POLARSSL_MODE_CBC)

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

Definition at line 111 of file cipher.c.

void cipher_init ( cipher_context_t * ctx )

Initialize a cipher_context (as NONE)

Definition at line 126 of file cipher.c.

int cipher_init_ctx	(	cipher_context_t *	ctx,
		const cipher_info_t *	cipher_info
	)

Initialises and fills the cipher context structure with the appropriate values.

Note:: Currently also clears structure. In future versions you will be required to call cipher_init() on the structure first.

Parameters:

ctx	context to initialise. May not be NULL.
cipher_info	cipher to use.

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

Definition at line 142 of file cipher.c.

const int* cipher_list ( void )

Returns the list of ciphers supported by the generic cipher module.

Returns:: a statically allocated array of ciphers, the last entry is 0.

Definition at line 65 of file cipher.c.

int cipher_reset ( cipher_context_t * ctx )

Finish preparation of the given context.

Parameters:

ctx	generic cipher context

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

Definition at line 239 of file cipher.c.

int cipher_self_test ( int verbose )

Checkup routine.

Returns:: 0 if successful, or 1 if the test failed

Definition at line 907 of file cipher.c.

int cipher_set_iv	(	cipher_context_t *	ctx,
		const unsigned char *	iv,
		size_t	iv_len
	)

Set the initialization vector (IV) or nonce.

Parameters:

ctx	generic cipher context
iv	IV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_len	IV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.

Returns:: 0 on success, or POLARSSL_ERR_CIPHER_BAD_INPUT_DATA

Note:: Some ciphers don't use IVs nor NONCE. For these ciphers, this function has no effect.

Definition at line 210 of file cipher.c.

int cipher_set_padding_mode	(	cipher_context_t *	ctx,
		cipher_padding_t	mode
	)

Set padding mode, for cipher modes that use padding.

(Default: PKCS7 padding.)

Parameters:

ctx	generic cipher context
mode	padding mode

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

Definition at line 690 of file cipher.c.

int cipher_setkey	(	cipher_context_t *	ctx,
		const unsigned char *	key,
		int	key_length,
		const operation_t	operation
	)

Set the key to use with the given context.

Parameters:

ctx	generic cipher context. May not be NULL. Must have been initialised using cipher_context_from_type or cipher_context_from_string.
key	The key to use.
key_length	key length to use, in bits.
operation	Operation that the key will be used for, either POLARSSL_ENCRYPT or POLARSSL_DECRYPT.

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

Definition at line 177 of file cipher.c.

int cipher_update	(	cipher_context_t *	ctx,
		const unsigned char *	input,
		size_t	ilen,
		unsigned char *	output,
		size_t *	olen
	)

Generic cipher update function.

Encrypts/decrypts using the given cipher context. Writes as many block size'd blocks of data as possible to output. Any data that cannot be written immediately will either be added to the next block, or flushed when cipher_final is called. Exception: for POLARSSL_MODE_ECB, expects single block in size (e.g. 16 bytes for AES)

Parameters:

ctx	generic cipher context
input	buffer holding the input data
ilen	length of the input data
output	buffer for the output data. Should be able to hold at least ilen + block_size. Cannot be the same buffer as input!
olen	length of the output data, will be filled with the actual number of bytes written.

Returns:: 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA if parameter verification fails, POLARSSL_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 cipher_finish(), must have ilen a multiple of the block size.

Definition at line 266 of file cipher.c.

int cipher_update_ad	(	cipher_context_t *	ctx,
		const unsigned char *	ad,
		size_t	ad_len
	)

Add additional data (for AEAD ciphers).

Currently only supported with GCM. Must be called exactly once, after cipher_reset().

Parameters:

ctx	generic cipher context
ad	Additional data to use.
ad_len	Length of ad.

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

Definition at line 250 of file cipher.c.

int cipher_write_tag	(	cipher_context_t *	ctx,
		unsigned char *	tag,
		size_t	tag_len
	)

Write tag for AEAD ciphers.

Currently only supported with GCM. Must be called after cipher_finish().

Parameters:

ctx	Generic cipher context
tag	buffer to write the tag
tag_len	Length of the tag to write

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

Definition at line 738 of file cipher.c.

Type:	Library
Created:	11 Jun 2015
Imports:	10
Forks:	0
Commits:	1
Dependents:	2
Dependencies:	0
Followers:	1

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