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cipher.h File Reference
This file contains an abstraction interface for use with the cipher primitives provided by the library. More...
Go to the source code of this file.
Detailed Description
This file contains an abstraction interface for use with the cipher primitives provided by the library.
It provides a common interface to all of the available cipher operations.
Definition in file cipher.h.
Typedef Documentation
typedef struct mbedtls_cipher_base_t mbedtls_cipher_base_t |
typedef struct mbedtls_cipher_context_t mbedtls_cipher_context_t |
Generic cipher context.
typedef struct mbedtls_cipher_info_t mbedtls_cipher_info_t |
Cipher information.
Allows calling cipher functions in a generic way.
typedef struct mbedtls_cmac_context_t mbedtls_cmac_context_t |
Enumeration Type Documentation
anonymous enum |
- Enumerator:
enum mbedtls_cipher_id_t |
Supported cipher types.
- Warning:
- RC4 and DES are considered weak ciphers and their use constitutes a security risk. Arm recommends considering stronger ciphers instead.
- Enumerator:
Supported cipher modes.
- Enumerator:
Supported {cipher type, cipher mode} pairs.
- Warning:
- RC4 and DES are considered weak ciphers and their use constitutes a security risk. Arm recommends considering stronger ciphers instead.
- Enumerator:
enum mbedtls_operation_t |
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.
- 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.
- Parameters:
-
ctx The generic cipher context. This must be initialized and and bound to a key. iv The IV to use, or NONCE_COUNTER for CTR-mode ciphers. This must be a readable buffer of at least iv_len
Bytes.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. This must be a readable buffer of at least ad_len
Bytes.ad_len The length of ad
.input The buffer holding the input data. This must be a readable buffer of at least ilen
Bytes.ilen The length of the input data. output The buffer for the output data. This must be able to hold at least ilen
Bytes.olen The length of the output data, to be updated with the actual number of Bytes written. This must not be NULL
.tag The buffer holding the authentication tag. This must be a readable buffer of at least tag_len
Bytes.tag_len The length of the authentication tag.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_AUTH_FAILED if data is not authentic.
- A cipher-specific error code on failure.
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. This must be initialized and bound to a key. iv The IV to use, or NONCE_COUNTER for CTR-mode ciphers. This must be a readable buffer of at least iv_len
Bytes.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. This must be a readable buffer of at least ad_len
Bytes.ad_len The length of ad
.input The buffer holding the input data. This must be a readable buffer of at least ilen
Bytes.ilen The length of the input data. output The buffer for the output data. This must be able to hold at least ilen
Bytes.olen The length of the output data, to be updated with the actual number of Bytes written. This must not be NULL
.tag The buffer for the authentication tag. This must be a writable buffer of at least tag_len
Bytes.tag_len The desired length of the authentication tag.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- A cipher-specific error code on failure.
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.
Currently supported with GCM and ChaCha20+Poly1305. This must be called after mbedtls_cipher_finish().
- Parameters:
-
ctx The generic cipher context. This must be initialized. tag The buffer holding the tag. This must be a readable buffer of at least tag_len
Bytes.tag_len The length of the tag to check.
- Returns:
0
on success.- A specific error code on failure.
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. This must be initialized. iv The IV to use, or NONCE_COUNTER for CTR-mode ciphers. This must be a readable buffer of at least iv_len
Bytes.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. This must be a readable buffer of at least ilen
Bytes.ilen The length of the input data in Bytes. output The buffer for the output data. This must be able to hold at least `ilen + block_size`. This 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. This must not be NULL
.
- Note:
- Some ciphers do not use IVs nor nonce. For these ciphers, use
iv
= NULL andiv_len
= 0.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption expecting a full block but not receiving one.
- MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting.
- A cipher-specific error code on failure.
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. This must be initialized and bound to a key. output The buffer to write data to. This needs to be a writable buffer of at least block_size
Bytes.olen The length of the data written to the output
buffer. This may not beNULL
.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED on decryption expecting a full block but not receiving one.
- MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding while decrypting.
- A cipher-specific error code on failure.
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.
- Parameters:
-
ctx The context to be freed. If this is NULL
, the function has no effect, otherwise this must point to an initialized context.
static unsigned int mbedtls_cipher_get_block_size | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
static mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
This function returns the mode of operation for the cipher.
For example, MBEDTLS_MODE_CBC.
- Parameters:
-
ctx The context of the cipher. This must be initialized.
- Returns:
- The mode of operation.
-
MBEDTLS_MODE_NONE if
ctx
has not been initialized.
static int mbedtls_cipher_get_iv_size | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
This function returns the size of the IV or nonce of the cipher, in Bytes.
- Parameters:
-
ctx The context of the cipher. This must be initialized.
- Returns:
- The recommended IV size if no IV has been set.
-
0
for ciphers not using an IV or a nonce. - The actual size if an IV has been set.
static int mbedtls_cipher_get_key_bitlen | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
This function returns the key length of the cipher.
- Parameters:
-
ctx The context of the cipher. This must be initialized.
- Returns:
- The key length of the cipher in bits.
-
MBEDTLS_KEY_LENGTH_NONE if ctx
has
not been initialized.
static const char* mbedtls_cipher_get_name | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
static mbedtls_operation_t mbedtls_cipher_get_operation | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
static mbedtls_cipher_type_t mbedtls_cipher_get_type | ( | const mbedtls_cipher_context_t * | ctx ) | [static] |
This function returns the type of the given cipher.
- Parameters:
-
ctx The context of the cipher. This must be initialized.
- Returns:
- The type of the cipher.
-
MBEDTLS_CIPHER_NONE if
ctx
has not been initialized.
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. This must not be NULL
.
- Returns:
- The cipher information structure associated with the given
cipher_name
. -
NULL
if the associated cipher information is not found.
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
. -
NULL
if the associated cipher information is not found.
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
. -
NULL
if the associated cipher information is not found.
void mbedtls_cipher_init | ( | mbedtls_cipher_context_t * | ctx ) |
const int* mbedtls_cipher_list | ( | void | ) |
This function retrieves the list of ciphers supported by the generic cipher module.
For any cipher identifier in the returned list, you can obtain the corresponding generic cipher information structure via mbedtls_cipher_info_from_type(), which can then be used to prepare a cipher context via mbedtls_cipher_setup().
- Returns:
- A statically-allocated array of cipher identifiers of type cipher_type_t. The last entry is zero.
int mbedtls_cipher_reset | ( | mbedtls_cipher_context_t * | ctx ) |
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.
- Note:
- Some ciphers do not use IVs nor nonce. For these ciphers, this function has no effect.
- Parameters:
-
ctx The generic cipher context. This must be initialized and bound to a cipher information structure. iv The IV to use, or NONCE_COUNTER for CTR-mode ciphers. This must be a readable buffer of at least iv_len
Bytes.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.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
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. This must be initialized and bound to a cipher information structure. mode The padding mode.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE if the selected padding mode is not supported.
- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode does not support padding.
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. This must be initialized and bound to a cipher information structure. key The key to use. This must be a readable buffer of at least key_bitlen
Bits.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 on parameter-verification failure.
- A cipher-specific error code on failure.
int mbedtls_cipher_setup | ( | mbedtls_cipher_context_t * | ctx, |
const mbedtls_cipher_info_t * | cipher_info | ||
) |
This function initializes a cipher context for use with the given cipher primitive.
- Parameters:
-
ctx The context to initialize. This must be initialized. cipher_info The cipher to use.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the cipher-specific context fails.
int mbedtls_cipher_setup_psa | ( | mbedtls_cipher_context_t * | ctx, |
const mbedtls_cipher_info_t * | cipher_info, | ||
size_t | taglen | ||
) |
This function initializes a cipher context for PSA-based use with the given cipher primitive.
- Note:
- See MBEDTLS_USE_PSA_CRYPTO for information on PSA.
- Parameters:
-
ctx The context to initialize. May not be NULL
.cipher_info The cipher to use. taglen For AEAD ciphers, the length in bytes of the authentication tag to use. Subsequent uses of mbedtls_cipher_auth_encrypt() or mbedtls_cipher_auth_decrypt() must provide the same tag length. For non-AEAD ciphers, the value must be 0
.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the cipher-specific context fails.
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.
- Note:
- If the underlying cipher is used in GCM mode, all calls to this function, except for the last one before mbedtls_cipher_finish(), must have
ilen
as a multiple of the block size of the cipher.
- Parameters:
-
ctx The generic cipher context. This must be initialized and bound to a key. input The buffer holding the input data. This must be a readable buffer of at least ilen
Bytes.ilen The length of the input data. output The buffer for the output data. This must be able to hold at least `ilen + block_size`. This 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. This must not be NULL
.
- Returns:
0
on success.- MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter-verification failure.
- MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an unsupported mode for a cipher.
- A cipher-specific error code on failure.
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.
Currently supported with GCM and ChaCha20+Poly1305. This must be called exactly once, after mbedtls_cipher_reset().
- Parameters:
-
ctx The generic cipher context. This must be initialized. ad The additional data to use. This must be a readable buffer of at least ad_len
Bytes.ad_len The length of ad
in Bytes.
- Returns:
0
on success.- A specific error code on failure.
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.
Currently supported with GCM and ChaCha20+Poly1305. This must be called after mbedtls_cipher_finish().
- Parameters:
-
ctx The generic cipher context. This must be initialized, bound to a key, and have just completed a cipher operation through mbedtls_cipher_finish() the tag for which should be written. tag The buffer to write the tag to. This must be a writable buffer of at least tag_len
Bytes.tag_len The length of the tag to write.
- Returns:
0
on success.- A specific error code on failure.
Generated on Tue Jul 12 2022 13:55:06 by
