| // Copyright 2023 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package rand |
| |
| import "internal/chacha8rand" |
| |
| // A ChaCha8 is a ChaCha8-based cryptographically strong |
| // random number generator. |
| type ChaCha8 struct { |
| state chacha8rand.State |
| } |
| |
| // NewChaCha8 returns a new ChaCha8 seeded with the given seed. |
| func NewChaCha8(seed [32]byte) *ChaCha8 { |
| c := new(ChaCha8) |
| c.state.Init(seed) |
| return c |
| } |
| |
| // Seed resets the ChaCha8 to behave the same way as NewChaCha8(seed). |
| func (c *ChaCha8) Seed(seed [32]byte) { |
| c.state.Init(seed) |
| } |
| |
| // Uint64 returns a uniformly distributed random uint64 value. |
| func (c *ChaCha8) Uint64() uint64 { |
| for { |
| x, ok := c.state.Next() |
| if ok { |
| return x |
| } |
| c.state.Refill() |
| } |
| } |
| |
| // UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. |
| func (c *ChaCha8) UnmarshalBinary(data []byte) error { |
| return chacha8rand.Unmarshal(&c.state, data) |
| } |
| |
| // MarshalBinary implements the encoding.BinaryMarshaler interface. |
| func (c *ChaCha8) MarshalBinary() ([]byte, error) { |
| return chacha8rand.Marshal(&c.state), nil |
| } |