Important changes to repositories hosted on mbed.com
Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.
To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.
It is also possible to export all your personal repositories from the account settings page.
Dependents: TYBLE16_simple_data_logger TYBLE16_MP3_Air
chacha20.h File Reference
This file contains ChaCha20 definitions and functions. More...
Go to the source code of this file.
Functions | |
| void | mbedtls_chacha20_init (mbedtls_chacha20_context *ctx) |
| This function initializes the specified ChaCha20 context. | |
| void | mbedtls_chacha20_free (mbedtls_chacha20_context *ctx) |
| This function releases and clears the specified ChaCha20 context. | |
| int | mbedtls_chacha20_setkey (mbedtls_chacha20_context *ctx, const unsigned char key[32]) |
| This function sets the encryption/decryption key. | |
| int | mbedtls_chacha20_starts (mbedtls_chacha20_context *ctx, const unsigned char nonce[12], uint32_t counter) |
| This function sets the nonce and initial counter value. | |
| int | mbedtls_chacha20_update (mbedtls_chacha20_context *ctx, size_t size, const unsigned char *input, unsigned char *output) |
| This function encrypts or decrypts data. | |
| int | mbedtls_chacha20_crypt (const unsigned char key[32], const unsigned char nonce[12], uint32_t counter, size_t size, const unsigned char *input, unsigned char *output) |
| This function encrypts or decrypts data with ChaCha20 and the given key and nonce. | |
| int | mbedtls_chacha20_self_test (int verbose) |
| The ChaCha20 checkup routine. | |
Detailed Description
This file contains ChaCha20 definitions and functions.
ChaCha20 is a stream cipher that can encrypt and decrypt information. ChaCha was created by Daniel Bernstein as a variant of its Salsa cipher https://cr.yp.to/chacha/chacha-20080128.pdf ChaCha20 is the variant with 20 rounds, that was also standardized in RFC 7539.
Definition in file chacha20.h.
Function Documentation
| int mbedtls_chacha20_crypt | ( | const unsigned char | key[32], |
| const unsigned char | nonce[12], | ||
| uint32_t | counter, | ||
| size_t | size, | ||
| const unsigned char * | input, | ||
| unsigned char * | output | ||
| ) |
This function encrypts or decrypts data with ChaCha20 and the given key and nonce.
Since ChaCha20 is a stream cipher, the same operation is used for encrypting and decrypting data.
- Warning:
- You must never use the same (key, nonce) pair more than once. This would void any confidentiality guarantees for the messages encrypted with the same nonce and key.
- Note:
- The
inputandoutputpointers must either be equal or point to non-overlapping buffers.
- Parameters:
-
key The encryption/decryption key. This must be 32Bytes in length.nonce The nonce. This must be 12Bytes in size.counter The initial counter value. This is usually 0.size The length of the input data in Bytes. input The buffer holding the input data. This pointer can be NULLif `size == 0`.output The buffer holding the output data. This must be able to hold sizeBytes. This pointer can beNULLif `size == 0`.
- Returns:
0on success.- A negative error code on failure.
Definition at line 320 of file chacha20.c.
| void mbedtls_chacha20_free | ( | mbedtls_chacha20_context * | ctx ) |
This function releases and clears the specified ChaCha20 context.
- Parameters:
-
ctx The ChaCha20 context to clear. This may be NULL, in which case this function is a no-op. If it is notNULL, it must point to an initialized context.
Definition at line 199 of file chacha20.c.
| void mbedtls_chacha20_init | ( | mbedtls_chacha20_context * | ctx ) |
This function initializes the specified ChaCha20 context.
It must be the first API called before using the context.
It is usually followed by calls to mbedtls_chacha20_setkey() and mbedtls_chacha20_starts(), then one or more calls to to mbedtls_chacha20_update(), and finally to mbedtls_chacha20_free().
- Parameters:
-
ctx The ChaCha20 context to initialize. This must not be NULL.
Definition at line 188 of file chacha20.c.
| int mbedtls_chacha20_self_test | ( | int | verbose ) |
The ChaCha20 checkup routine.
- Returns:
0on success.-
1on failure.
Definition at line 535 of file chacha20.c.
| int mbedtls_chacha20_setkey | ( | mbedtls_chacha20_context * | ctx, |
| const unsigned char | key[32] | ||
| ) |
This function sets the encryption/decryption key.
- Note:
- After using this function, you must also call
mbedtls_chacha20_starts()to set a nonce before you start encrypting/decrypting data withmbedtls_chacha_update().
- Parameters:
-
ctx The ChaCha20 context to which the key should be bound. It must be initialized. key The encryption/decryption key. This must be 32Bytes in length.
- Returns:
0on success.- MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA if ctx or key is NULL.
Definition at line 207 of file chacha20.c.
| int mbedtls_chacha20_starts | ( | mbedtls_chacha20_context * | ctx, |
| const unsigned char | nonce[12], | ||
| uint32_t | counter | ||
| ) |
This function sets the nonce and initial counter value.
- Note:
- A ChaCha20 context can be re-used with the same key by calling this function to change the nonce.
- Warning:
- You must never use the same nonce twice with the same key. This would void any confidentiality guarantees for the messages encrypted with the same nonce and key.
- Parameters:
-
ctx The ChaCha20 context to which the nonce should be bound. It must be initialized and bound to a key. nonce The nonce. This must be 12Bytes in size.counter The initial counter value. This is usually 0.
- Returns:
0on success.- MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA if ctx or nonce is NULL.
Definition at line 232 of file chacha20.c.
| int mbedtls_chacha20_update | ( | mbedtls_chacha20_context * | ctx, |
| size_t | size, | ||
| const unsigned char * | input, | ||
| unsigned char * | output | ||
| ) |
This function encrypts or decrypts data.
Since ChaCha20 is a stream cipher, the same operation is used for encrypting and decrypting data.
- Note:
- The
inputandoutputpointers must either be equal or point to non-overlapping buffers. -
mbedtls_chacha20_setkey()andmbedtls_chacha20_starts()must be called at least once to setup the context before this function can be called. - This function can be called multiple times in a row in order to encrypt of decrypt data piecewise with the same key and nonce.
- Parameters:
-
ctx The ChaCha20 context to use for encryption or decryption. It must be initialized and bound to a key and nonce. size The length of the input data in Bytes. input The buffer holding the input data. This pointer can be NULLif `size == 0`.output The buffer holding the output data. This must be able to hold sizeBytes. This pointer can beNULLif `size == 0`.
- Returns:
0on success.- A negative error code on failure.
Definition at line 255 of file chacha20.c.
Generated on Tue Jul 12 2022 13:55:06 by
1.7.2