Scrypt 不止是加密演算法，也是萊特幣的挖礦演算法

. * * @param password * Password. * @param salt * Salt. * @param cost * Overall CPU/MEM cost parameter. 2^15 for testing, but 2^20 recommended. * @param blocksize * Block size for each mixing loop (memory usage). * @param parallel * Parallelization to control the number of independent mixing loops. * @param length * Intended length of the derived key. * * @return The derived key. * * @throws NoSuchAlgorithmException * when HMAC_SHA256 is not available. * @throws IllegalArgumentException * when parameters invalid */ protected static byte[] scrypt(byte[] password, byte[] salt, int cost, int blocksize, int parallel, int length) throws GeneralSecurityException { if (cost Integer.MAX_VALUE / 128 / blocksize) throw new IllegalArgumentException("Parameter cost is too large"); if (blocksize > Integer.MAX_VALUE / 128 / parallel) throw new IllegalArgumentException("Parameter blocksize is too large"); Mac mac = Mac.getInstance("HmacSHA256"); mac.init(new SecretKeySpec(password, "HmacSHA256")); byte[] key = new byte[length]; byte[] b1 = new byte[128 * blocksize * parallel]; byte[] xy = new byte[256 * blocksize]; byte[] v1 = new byte[128 * blocksize * cost]; pbkdf2(mac, salt, 1, b1, parallel * 128 * blocksize); for (int i = 0; i >> (32 - right)); } private static void salsa(byte[] b1) { int[] base32 = new int[16]; for (int i = 0; i 0; i -= 2) { x1[4] ^= r1(x1[0] + x1[12], 7); x1[8] ^= r1(x1[4] + x1[0], 9); x1[12] ^= r1(x1[8] + x1[4], 13); x1[0] ^= r1(x1[12] + x1[8], 18); x1[9] ^= r1(x1[5] + x1[1], 7); x1[13] ^= r1(x1[9] + x1[5], 9); x1[1] ^= r1(x1[13] + x1[9], 13); x1[5] ^= r1(x1[1] + x1[13], 18); x1[14] ^= r1(x1[10] + x1[6], 7); x1[2] ^= r1(x1[14] + x1[10], 9); x1[6] ^= r1(x1[2] + x1[14], 13); x1[10] ^= r1(x1[6] + x1[2], 18); x1[3] ^= r1(x1[15] + x1[11], 7); x1[7] ^= r1(x1[3] + x1[15], 9); x1[11] ^= r1(x1[7] + x1[3], 13); x1[15] ^= r1(x1[11] + x1[7], 18); x1[1] ^= r1(x1[0] + x1[3], 7); x1[2] ^= r1(x1[1] + x1[0], 9); x1[3] ^= r1(x1[2] + x1[1], 13); x1[0] ^= r1(x1[3] + x1[2], 18); x1[6] ^= r1(x1[5] + x1[4], 7); x1[7] ^= r1(x1[6] + x1[5], 9); x1[4] ^= r1(x1[7] + x1[6], 13); x1[5] ^= r1(x1[4] + x1[7], 18); x1[11] ^= r1(x1[10] + x1[9], 7); x1[8] ^= r1(x1[11] + x1[10], 9); x1[9] ^= r1(x1[8] + x1[11], 13); x1[10] ^= r1(x1[9] + x1[8], 18); x1[12] ^= r1(x1[15] + x1[14], 7); x1[13] ^= r1(x1[12] + x1[15], 9); x1[14] ^= r1(x1[13] + x1[12], 13); x1[15] ^= r1(x1[14] + x1[13], 18); } for (int i = 0; i > 0 & 0xff); b1[i * 4 + 1] = (byte) (base32[i] >> 8 & 0xff); b1[i * 4 + 2] = (byte) (base32[i] >> 16 & 0xff); b1[i * 4 + 3] = (byte) (base32[i] >> 24 & 0xff); } } private static void blockxor(byte[] s1, int si, byte[] d1, int di, int length) { for (int i = 0; i > 24 & 0xff); block[salt.length + 1] = (byte) (i >> 16 & 0xff); block[salt.length + 2] = (byte) (i >> 8 & 0xff); block[salt.length + 3] = (byte) (i >> 0 & 0xff); mac.update(block); mac.doFinal(u1, 0); System.arraycopy(u1, 0, t1, 0, len); for (int j = 1; j

下面是 Scrypt 演算法的呼叫。

package com.cv4j.blockchain.study.scrypt;

import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;

/**
 * Created by tony on 2018/8/5.
 */
public class Test {

    public static void main(String[] args) {

        byte[] password = new byte[0];
        try {
            password = "123456".getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        byte[] salt = new byte[0];
        try {
            salt = "abcdefg".getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        long start = System.currentTimeMillis();

        byte[] scrypt = new byte[0];
        try {
            scrypt = Scrypt.scrypt(password,salt,131072,8,1,32);
        } catch (GeneralSecurityException e) {
            e.printStackTrace();
        }

        String str = HashUtils.encodeBase64(scrypt);

        long end = System.currentTimeMillis();
        System.out.println("加密後的值:"+str);
        System.out.println("花費時間:"+(end-start)+" ms");
    }
}

下面的程式碼實現了真正的加密

scrypt = Scrypt.scrypt(password,salt,131072,8,1,32);

加密後的位元組陣列還需要使用 Base64 進行 encode。

完整的 Scrypt Java 版本已經放到github上。
github地址：