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cipher.c File Reference

cipher.c File Reference

Generic cipher wrapper for mbed TLS. More...

Go to the source code of this file.

Functions

const int * cipher_list (void)
 Returns the list of ciphers supported by the generic cipher module.
const cipher_info_tcipher_info_from_type (const cipher_type_t cipher_type)
 Returns the cipher information structure associated with the given cipher type.
const cipher_info_tcipher_info_from_string (const char *cipher_name)
 Returns the cipher information structure associated with the given cipher name.
const cipher_info_tcipher_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>

Copyright (C) 2006-2014, ARM Limited, All Rights Reserved

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:
ctxgeneric cipher context
ivIV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_lenIV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
adAdditional data to be authenticated.
ad_lenLength of ad.
inputbuffer holding the input data
ilenlength of the input data
outputbuffer for the output data. Should be able to hold at least ilen.
olenlength of the output data, will be filled with the actual number of bytes written.
tagbuffer holding the authentication tag
tag_lenlength 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:
ctxgeneric cipher context
ivIV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_lenIV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
adAdditional data to authenticate.
ad_lenLength of ad.
inputbuffer holding the input data
ilenlength of the input data
outputbuffer for the output data. Should be able to hold at least ilen.
olenlength of the output data, will be filled with the actual number of bytes written.
tagbuffer for the authentication tag
tag_lendesired 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:
ctxGeneric cipher context
tagBuffer holding the tag
tag_lenLength 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:
ctxgeneric cipher context
ivIV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_lenIV length for ciphers with variable-size IV; discarded by ciphers with fixed-size IV.
inputbuffer holding the input data
ilenlength of the input data
outputbuffer for the output data. Should be able to hold at least ilen + block_size. Cannot be the same buffer as input!
olenlength 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:
ctxGeneric cipher context
outputbuffer to write data to. Needs block_size available.
olenlength 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:
ctxFree 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_nameName 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_typeType 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_idId of the cipher to search for (e.g. POLARSSL_CIPHER_ID_AES)
key_lengthLength of the key in bits
modeCipher 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:
ctxcontext to initialise. May not be NULL.
cipher_infocipher 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:
ctxgeneric 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:
ctxgeneric cipher context
ivIV to use (or NONCE_COUNTER for CTR-mode ciphers)
iv_lenIV 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:
ctxgeneric cipher context
modepadding 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:
ctxgeneric cipher context. May not be NULL. Must have been initialised using cipher_context_from_type or cipher_context_from_string.
keyThe key to use.
key_lengthkey length to use, in bits.
operationOperation 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:
ctxgeneric cipher context
inputbuffer holding the input data
ilenlength of the input data
outputbuffer for the output data. Should be able to hold at least ilen + block_size. Cannot be the same buffer as input!
olenlength 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:
ctxgeneric cipher context
adAdditional data to use.
ad_lenLength 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:
ctxGeneric cipher context
tagbuffer to write the tag
tag_lenLength of the tag to write
Returns:
0 on success, or a specific error code.

Definition at line 738 of file cipher.c.