pw::crypto::chacha20 Namespace Reference

Overview

ChaCha20 stream cipher.

This module provides a backend-agnostic API for the ChaCha20 stream cipher as defined in RFC 8439.

Functions
Status	Crypt (span< const std::byte > key, span< const std::byte > nonce, span< const std::byte > input, span< std::byte > output)

Variables
constexpr size_t	kKeySizeBytes = 32
constexpr size_t	kNonceSizeBytes = 12

Function Documentation

Crypt()

Status pw::crypto::chacha20::Crypt ( span< const std::byte >  key, span< const std::byte >  nonce, span< const std::byte >  input, span< std::byte >  output  )

inline

Performs ChaCha20 encryption or decryption. Since ChaCha20 is a stream cipher, encryption and decryption are the same operation. InitialCounter had been removed from the cacnonical API and is hardcoded to 0 for simplicity of a one-shot only implementation.

Parameters

[in]	key	The 256-bit secret key.
[in]	nonce	The 96-bit nonce. MUST be unique for each encryption with the same key.
[in]	input	The data to encrypt or decrypt.
[out]	output	The buffer to store the result. Must be at least as large as input. In-place operation is allowed (input == output).

Returns

OkStatus() on success. or Status::InvalidArgument() if key, nonce, or buffer sizes are incorrect. Status::Internal() for any other backend-related errors.