int wc_Chacha_SetIV(    ChaCha * ctx,    const byte * inIv,    word32 counter)

• wc_Chacha_SetKey
• wc_Chacha_Process

Return:

• 0 Returned upon successfully setting the initialization vector
• BAD_FUNC_ARG returned if there is an error processing the ctx input argument

Example

ChaCha enc;// initialize enc with wc_Chacha_SetKeybyte iv[12];// initialize ivif( wc_Chacha_SetIV(&enc, iv, 0) != 0) {    // error initializing ChaCha structure}

function wc_Chacha_Process

int wc_Chacha_Process(    ChaCha * ctx,    byte * cipher,    const byte * plain,    word32 msglen)

This function processes the text from the buffer input, encrypts or decrypts it, and stores the result in the buffer output.

Parameters:

• ctx pointer to the ChaCha structure on which to set the iv
• output pointer to a buffer in which to store the output ciphertext or decrypted plaintext
• input pointer to the buffer containing the input plaintext to encrypt or the input ciphertext to decrypt
• msglen length of the message to encrypt or the ciphertext to decrypt

See:

• wc_Chacha_SetKey
• wc_Chacha_Process

Return:

• 0 Returned upon successfully encrypting or decrypting the input
• BAD_FUNC_ARG returned if there is an error processing the ctx input argument

Example

ChaCha enc;// initialize enc with wc_Chacha_SetKey and wc_Chacha_SetIVbyte plain[] = { // initialize plaintext };byte cipher[sizeof(plain)];if( wc_Chacha_Process(&enc, cipher, plain, sizeof(plain)) != 0) {    // error processing ChaCha cipher}

function wc_Chacha_SetKey

int wc_Chacha_SetKey(    ChaCha * ctx,    const byte * key,    word32 keySz)

This function sets the key for a ChaCha object, initializing it for use as a cipher. It should be called before setting the nonce with wc_Chacha_SetIV, and before using it for encryption with wc_Chacha_Process.

Parameters:

• ctx pointer to the ChaCha structure in which to set the key
• key pointer to a buffer containing the 16 or 32 byte key with which to initialize the ChaCha structure
• keySz the length of the key passed in

See:

• wc_Chacha_SetIV
• wc_Chacha_Process

Return:

• 0 Returned upon successfully setting the key
• BAD_FUNC_ARG returned if there is an error processing the ctx input argument or if the key is not 16 or 32 bytes long

Example

ChaCha enc;byte key[] = { // initialize key };if( wc_Chacha_SetKey(&enc, key, sizeof(key)) != 0) {    // error initializing ChaCha structure}

function wc_XChacha_SetKey

int wc_XChacha_SetKey(    ChaCha * ctx,    const byte * key,    word32 keySz,    const byte * nonce,    word32 nonceSz,    word32 counter)

This function sets the key and nonce for an XChaCha cipher context. XChaCha extends ChaCha20 to use a 192-bit nonce instead of 96 bits, providing better security for applications that need to encrypt many messages with the same key.

Parameters:

• ctx pointer to the ChaCha structure to initialize
• key pointer to the key buffer (16 or 32 bytes)
• keySz length of the key in bytes (16 or 32)
• nonce pointer to the nonce buffer (must be 24 bytes)
• nonceSz length of the nonce in bytes (must be 24)
• counter initial block counter value (usually 0)

See:

• wc_Chacha_SetKey
• wc_Chacha_SetIV
• wc_Chacha_Process

Return:

• 0 On success.
• BAD_FUNC_ARG If ctx, key, or nonce is NULL, or if keySz is invalid, or if nonceSz is not XCHACHA_NONCE_BYTES (24 bytes).
• Other negative values on error.

Example

ChaCha ctx;byte key[32] = { }; // 256-bit keybyte nonce[24] = { }; // 192-bit noncebyte plaintext[100] = { }; // data to encryptbyte ciphertext[100];int ret = wc_XChacha_SetKey(&ctx, key, 32, nonce, 24, 0);if (ret != 0) {    // error setting XChaCha key}wc_Chacha_Process(&ctx, ciphertext, plaintext, 100);

Updated on 2026-02-20 at 02:00:32 +0000