Template Class ChaCha

Class Documentation

template<std::uint8_t R = 20>
class ChaCha

Public Types

using result_type = std::uint64_t
using input_word = std::uint64_t
using matrix_word = std::uint32_t
using matrix_type = std::array<matrix_word, MATRIX_WORDCOUNT>
using result_cache_type = std::array<result_type, MATRIX_WORDCOUNT / 2>

Public Functions

inline explicit ChaCha(const std::array<matrix_word, KEY_WORDCOUNT> key, const input_word counter, const input_word nonce) noexcept

Construct a scalar ChaCha generator with given key, counter and nonce.

Parameters:

  • key – A 256-bit key, divided up into eight 32-bit words.

  • counter – Initial value of the counter.

  • nonce – Initial value of the nonce.

inline constexpr result_type (operator())() noexcept

Generates the next 64-bit output.

Returns:

The next 64-bit output.

inline constexpr double uniform() noexcept

Generates a uniform random number in the range [0, 1).

Returns:

A uniform random number.

inline constexpr matrix_type block() noexcept

Generates the next 64-byte ChaCha block.

Returns:

The next 64-byte ChaCha block.

inline constexpr matrix_type getState() const noexcept

Returns the state of the generator; a 4x4 matrix.

Returns:

State of the generator.

Public Static Functions

static inline constexpr auto() min () noexcept
static inline constexpr auto() max () noexcept

Protected Static Attributes

static constexpr auto MATRIX_WORDCOUNT = std::uint8_t{16}
static constexpr auto KEY_WORDCOUNT = std::uint8_t{8}