PBKDF2 Key Derivation

pbkdf2-gen.go

// Copyright 2021 Abhijit Bose. All rights reserved.
// Use of this source code is governed by a Apache 2.0 license

package main

import (
	"bytes"
	"crypto/rand"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"

	"golang.org/x/crypto/pbkdf2"
)

func main() {
	key := []byte("Test Password") // Source Key
	rounds := 4096                 // Number of Rounds to be used for PBKDF2

	// Create the Salt
	salt := make([]byte, 8)
	if _, err := io.ReadFull(rand.Reader, salt); err != nil {
		panic(err)
	}

	// Perform Key Derivation
	dk := pbkdf2.Key(key, salt, rounds, sha256.Size, sha256.New)
	fmt.Println("Derived Key:", hex.EncodeToString(dk))
	fmt.Println("Salt:", hex.EncodeToString(salt))
	fmt.Println("Rounds:", uint64(rounds))

	// Compress the Data Into a Single Slice
	//
	// Format: Rounds[8byte] | salt[8bytes] | derivedKey[dk 32bytes SHA2-256]
	//
	//   buf := make([]byte, 8+len(dk)+len(salt))
	//
	result := bytes.NewBuffer(nil) // Use Bytes Buffer for Easier assembly
	// Add the Rounds
	resRounds := uint64(rounds)
	for i := 0; i < 8; i++ {
		result.WriteByte(byte(resRounds & uint64(0x0FF)))
		resRounds >>= 8
	}
	// Add the Other Elements
	result.Write(salt)
	result.Write(dk)

	fmt.Println("Compressed Result: \n", hex.EncodeToString(result.Bytes()))

}