ChaCha20¶

Encrypt¶

To test a function that encrypts with ChaCha20 only, its name must conform to the following convention:

CC_ChaCha20_encrypt

Its signature must be:

void CC_ChaCha20_encrypt( uint8_t *buffer, size_t buffer_size, const uint8_t key[32], const uint8_t *nonce, size_t nonce_size, uint64_t init_counter, )¶

Parameters:

buffer – [In/Out] A buffer containing the plaintext to encrypt, and to store the resulting ciphertext.
buffer_size – [In] The size of the buffer in bytes.
key – [In] The 32-byte symmetric key.
nonce – [In] The nonce.
nonce_size – [In] The size of the nonce in bytes.
init_counter – [In] An absolute position within the keystream in bytes to seek before encrypting.

Example:

void CC_ChaCha20_encrypt(uint8_t *buffer, size_t buffer_size,
                        const uint8_t key[32],
                        const uint8_t *nonce, size_t nonce_size,
                        uint64_t init_counter);

Decrypt¶

To test a function that decrypts with ChaCha20 only, its name must conform to the following convention:

CC_ChaCha20_decrypt

Its signature must be:

void CC_ChaCha20_decrypt( uint8_t *buffer, size_t buffer_size, const uint8_t key[32], const uint8_t *nonce, size_t nonce_size, uint64_t init_counter, )¶

Parameters:

buffer – [In/Out] A buffer containing the ciphertext to decrypt, and to store the resulting plaintext.
buffer_size – [In] The size of the buffer in bytes.
key – [In] The 32-byte symmetric key.
nonce – [In] The nonce.
nonce_size – [In] The size of the nonce in bytes.
init_counter – [In] An absolute position within the keystream in bytes to seek before decrypting.

Example:

void CC_ChaCha20_encrypt(uint8_t *buffer, size_t buffer_size,
                        const uint8_t key[32],
                        const uint8_t *nonce, size_t nonce_size,
                        uint64_t init_counter);

Encrypt with Poly1305¶

To test a function that encrypts with ChaCha20-Poly1305, its name must conform to the following convention:

CC_ChaCha20_Poly1305_encrypt

Its signature must be:

void CC_ChaCha20_Poly1305_encrypt( uint8_t *buffer, size_t buffer_size, uint8_t mac[16], const uint8_t key[32], const uint8_t *nonce, size_t nonce_size, const uint8_t *aad, size_t aad_size, )¶

Parameters:

buffer – [In/Out] A buffer containing the plaintext to encrypt, and to store the resulting ciphertext.
buffer_size – [In] The size of the buffer in bytes.
mac – [Out] A buffer to store the resulting 16-byte MAC tag.
key – [In] The 32-byte symmetric key.
nonce – [In] The nonce.
nonce_size – [In] The size of the nonce in bytes.
aad – [In] The optional associated data. NULL if not used.
aad_size – [In] The size of the associated data. 0 if not used.

Example:

void CC_ChaCha20_Poly1305_encrypt(uint8_t *buffer, size_t buffer_size,
                                 uint8_t mac[16],
                                 const uint8_t key[32],
                                 const uint8_t *nonce, size_t nonce_size,
                                 const uint8_t *aad, size_t aad_size);

Decrypt with Poly1305¶

To test a function that decrypts with ChaCha20-Poly1305, its name must conform to the following convention:

CC_ChaCha20_Poly1305_decrypt

Its signature must be:

int CC_ChaCha20_Poly1305_decrypt( uint8_t *buffer, size_t buffer_size, const uint8_t key[32], const uint8_t *nonce, size_t nonce_size, const uint8_t *aad, size_t aad_size, const uint8_t mac[16], )¶

Parameters:

buffer – [In/Out] A buffer containing the ciphertext to decrypt, and to store the resulting plaintext. It is ignored if the function returns -2.
buffer_size – [In] The size of the buffer in bytes.
key – [In] The 32-byte symmetric key.
nonce – [In] The nonce.
nonce_size – [In] The size of the nonce in bytes.
aad – [In] The optional associated data. NULL if not used.
aad_size – [In] The size of the associated data. 0 if not used.
mac – [In] The 16-byte MAC tag to verify.

Returns:

A status value.

Return values:

0 – OK.
-1 – The MAC verification failed.

Example:

int CC_ChaCha20_Poly1305_decrypt(uint8_t *buffer, size_t buffer_size,
                                 const uint8_t key[32],
                                 const uint8_t *nonce, size_t nonce_size,
                                 const uint8_t *aad, size_t aad_size,
                                 const uint8_t mac[16]);