Macros
#define	IQR_CHACHA20_KEY_SIZE 32

#define	IQR_CHACHA20_NONCE_SIZE 12

Functions
IQR_API iqr_retval	iqr_ChaCha20Encrypt (const uint8_t key, size_t key_size, const uint8_t nonce, size_t nonce_size, uint32_t counter, const uint8_t plaintext, size_t plaintext_size, uint8_t ciphertext, size_t ciphertext_size)

IQR_API iqr_retval	iqr_ChaCha20Decrypt (const uint8_t key, size_t key_size, const uint8_t nonce, size_t nonce_size, uint32_t counter, const uint8_t ciphertext, size_t ciphertext_size, uint8_t plaintext, size_t plaintext_size)

Macro Definition Documentation

§ IQR_CHACHA20_KEY_SIZE

#define IQR_CHACHA20_KEY_SIZE 32

The size of a ChaCha20 key in bytes (256 bits).

§ IQR_CHACHA20_NONCE_SIZE

#define IQR_CHACHA20_NONCE_SIZE 12

The size of a ChaCha20 nonce in bytes (96 bits).

Function Documentation

§ iqr_ChaCha20Decrypt()

IQR_API iqr_retval iqr_ChaCha20Decrypt	(	const uint8_t *	key,
		size_t	key_size,
		const uint8_t *	nonce,
		size_t	nonce_size,
		uint32_t	counter,
		const uint8_t *	ciphertext,
		size_t	ciphertext_size,
		uint8_t *	plaintext,
		size_t	plaintext_size
	)

Decrypt a ciphertext message using the ChaCha20 stream cipher, standardized in RFC-7539.

ChaCha20 is its own inverse so a second application of the encryption function with identical key, counter, and nonce is equivalent to calling the decryption function.

The plaintext and ciphertext buffers cannot overlap except if they are pointers to the same location with the same size. IQR_EPTROVERLAP will be returned if the buffers overlap and/or have different sizes.

Parameters

[in]	key	A buffer containing 256 bits of keying material.
[in]	key_size	Size of the key buffer in bytes. This value must always be equal to `IQR_CHACHA20_KEY_SIZE`.
[in]	nonce	A buffer containing a 96-bit nonce.
[in]	nonce_size	Size of the nonce buffer in bytes. This value must always be equal to `IQR_CHACHA20_NONCE_SIZE`.
[in]	counter	Initial block counter value.
[in]	ciphertext	A buffer containing the ciphertext message to be decrypted.
[in]	ciphertext_size	The size of buffer ciphertext in bytes.
[out]	plaintext	The buffer to which the decrypted message will be written.
[in]	plaintext_size	The size of buffer plaintext in bytes. This must be greater than or equal to ciphertext_size.

Returns: IQR_OK on success, or a value from iqr_retval.h when an error occurs.

§ iqr_ChaCha20Encrypt()

IQR_API iqr_retval iqr_ChaCha20Encrypt	(	const uint8_t *	key,
		size_t	key_size,
		const uint8_t *	nonce,
		size_t	nonce_size,
		uint32_t	counter,
		const uint8_t *	plaintext,
		size_t	plaintext_size,
		uint8_t *	ciphertext,
		size_t	ciphertext_size
	)

Encrypt a plaintext message using the ChaCha20 stream cipher, standardized in RFC-7539.

ChaCha20 is its own inverse so a second application of the encryption function with identical key, counter, and nonce is equivalent to calling the decryption function.

The plaintext and ciphertext buffers cannot overlap except if they are pointers to the same location with the same size. IQR_EPTROVERLAP will be returned if the buffers overlap and/or have different sizes.

Parameters

[in]	key	A buffer containing 256 bits of keying material.
[in]	key_size	Size of the key buffer in bytes. This value must always be equal to `IQR_CHACHA20_KEY_SIZE`.
[in]	nonce	A buffer containing a 96-bit nonce.
[in]	nonce_size	Size of the nonce buffer in bytes. This value must always be equal to `IQR_CHACHA20_NONCE_SIZE`.
[in]	counter	Initial block counter value.
[in]	plaintext	A buffer containing the plaintext message to be encrypted.
[in]	plaintext_size	The size of plaintext in bytes.
[out]	ciphertext	The buffer to which the encrypted message will be written.
[in]	ciphertext_size	The size of ciphertext in bytes. This must be greater than or equal to plaintext_size.

Returns: IQR_OK on success, or a value from iqr_retval.h when an error occurs.

Detailed Description

ISARA Quantum Resistant Toolkit external interface for the ChaCha20 stream cipher.

ChaCha20 is a refinement of the Salsa20 stream cipher. It uses 256 bits of keying material, a 32-bit counter, and a 96-bit nonce to encrypt an arbitrary length plaintext. The output ciphertext is the same length as the plaintext.

The specification for ChaCha20 can be found in RFC-7539.

License: The code and other content set out herein is not in the public domain, is considered a trade secret and is confidential to ISARA Corporation. Use, reproduction or distribution, in whole or in part, of such code or other content is strictly prohibited except by express written permission of ISARA Corporation. Please contact ISARA Corporation at info@.nosp@m.isar.nosp@m.a.com for more information.

Macros