johnsonjh/gfcp

// Copyright © 2021 Jeffrey H. Johnson <trnsz@pobox.com>.
// Copyright © 2015 Daniel Fu <daniel820313@gmail.com>.
// Copyright © 2019 Loki 'l0k18' Verloren <stalker.loki@protonmail.ch>.
// Copyright © 2021 Gridfinity, LLC. <admin@gridfinity.com>.
//
// All rights reserved.
//
// All use of this code is governed by the MIT license.
// The complete license is available in the LICENSE file.

package gfcp

import (
    "crypto/rand"
    "io"
)

// Entropy defines a entropy source
type Entropy interface {
    Init()
    Fill(
        nonce []byte,
    )
}

// Nonce ...
type Nonce struct {
    seed []byte
}

// Init ...
func (
    n *Nonce,
) Init() {
}

// Fill ...
func (
    n *Nonce,
) Fill(
    nonce []byte,
) {
    var err error
    if n.seed[0] == 0 {
        _, err = io.ReadFull(
            rand.Reader,
            n.seed,
        )
        if err != nil {
            panic(
                "io.ReadFull failure",
            )
        }
    }
    copy(
        nonce,
        n.seed,
    )
}