最近学习区块链的知识，学习过程中，了解了区块链中常用的几种算法。有一大胆的想法，把这些算法整理成为一个清单，并找出算法论文，目前市场应用，以及实现代码。如果还有其他的算法或者代币，也欢迎大家推荐加入此清单。
SHA-256
-
介绍：SHA代表安全散列算法（Secure Hash Algorithm），SHA-256是由美国国家安全局(NSA)设计的SHA-2加密散列函数的成员(SHA-2的其他成员有SHA-224、SHA-384、SHA-512)。加密散列函数是对数字数据运行的数学运算，通过将所计算的“散列”与已知的散列值进行比较，人们可以确定数据的完整性。 单向散列可以从任意数据生成，但不能从散列生成数据。在比特币等多个区块链应用中的多个环节被使用。
-
论文：Courtois, Nicolas T., Marek Grajek, and Rahul Naik. "Optimizing sha256 in bitcoin mining." International Conference on Cryptography and Security Systems. Springer, Berlin, Heidelberg, 2014.
-
应用：Bitcoin(BTC)、BitcoinCash(BCH)、Peercoin(PPC)、Zetacoin(ZET)、Universal(UNIT)、Deutsche eMark(DEM)、AUR-SHA(AUR)、DGB-SHA(DGB)
-
算法实现：SHA-256算法要求输入报文的最大长度不能超过2^64bit，输入按512bit分组进行处理，产生的输出是一个256bit的报文摘要。
SHA256.h
``` cpp
#ifndef _SHA_256_H
#define _SHA_256_H
#include
using namespace std;
typedef unsigned int UInt32;
//六个逻辑函数
#define Conditional(x,y,z) ((x&y)^((~x)&z))
#define Majority(x,y,z) ((x&y)^(x&z)^(y&z))
#define LSigma_0(x) (ROTL(x,30)^ROTL(x,19)^ROTL(x,10))
#define LSigma_1(x) (ROTL(x,26)^ROTL(x,21)^ROTL(x,7))
#define SSigma_0(x) (ROTL(x,25)^ROTL(x,14)^SHR(x,3))
#define SSigma_1(x) (ROTL(x,15)^ROTL(x,13)^SHR(x,10))
//信息摘要结构
struct Message_Digest{
UInt32 H[8];
};
//SHA256类
class SHA256
{
public:
SHA256(){INIT();};
~SHA256(){};
Message_Digest DEAL(UInt32 W[16]);//处理512比特数据，返回信息摘要
private:
void INIT(); //初始杂凑值
UInt32 ROTR(UInt32 W,int n);//右旋转
UInt32 ROTL(UInt32 W,int n);//左旋转
UInt32 SHR(UInt32 W,int n); //右移位
private:
//信息摘要
Message_Digest MD;
};
#endif
```
SHA256.cpp
```
#include"SHA-256.h"
//64个32比特字的常数（前64个素数的立方根小数前32位）
const UInt32 K[64] = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
};
//初始化杂凑值（前8个素数的平方根小数前32位）
void SHA256::INIT(){
MD.H[0] = 0x6a09e667;
MD.H[1] = 0xbb67ae85;
MD.H[2] = 0x3c6ef372;
MD.H[3] = 0xa54ff53a;
MD.H[4] = 0x510e527f;
MD.H[5] = 0x9b05688c;
MD.H[6] = 0x1f83d9ab;
MD.H[7] = 0x5be0cd19;
}
//处理512比特数据，返回信息摘要
Message_Digest SHA256::DEAL(UInt32 M[16]){
int i;
UInt32 T1=0,T2=0;
UInt32 W[64]={0};
UInt32 A=0,B=0,C=0,D=0,E=0,F=0,G=0,H=0;
for(i=0;i<16;i++){
W[i] = M[i];
}
for(i=16;i<64;i++){
W[i] = SSigma_1(W[i-2])+W[i-7]+SSigma_0(W[i-15])+W[i-16];
}
A = MD.H[0];
B = MD.H[1];
C = MD.H[2];
D = MD.H[3];
E = MD.H[4];
F = MD.H[5];
G = MD.H[6];
H = MD.H[7];
cout<<"初始:";
cout<> n) & 0xFFFFFFFF) | (W) << (32-(n));
}
//左旋转
UInt32 SHA256::ROTL(UInt32 W,int n){
return ((W << n) & 0xFFFFFFFF) | (W) >> (32-(n));
}
//右移位
UInt32 SHA256::SHR(UInt32 W,int n){
return ((W >> n) & 0xFFFFFFFF);
}
```
test.cpp
```
#include
#include"SHA-256.h"
using namespace std;
typedef unsigned int UInt32;
typedef unsigned __int64 UInt64;
typedef unsigned char UChar;
#define Max 1000//最大字符数
SHA256 sha256=SHA256();
Message_Digest M_D;
UInt32 W[Max/4];//整型
UInt32 M[16]; //存分组信息
//压缩+显示
void compress(){
int i;
M_D = sha256.DEAL(M);
cout<<"哈希值： ";
for(i=0;i<8;i++){
cout<>(i-1)*8);
}
//无符号字符转换为无符号整型
for(i=0;i>Y;
PAD(Y);
system("pause");
return 0;
}
```
Scrypt
-
介绍：Scrypt是一个内存依赖型的hash算法。该算法是由著名的FreeBSD黑客Colin Percival为他的备份服务Tarsnap开发的。内存依赖顾名思义会占用很多内存空间，从而减少cpu负荷。由于其内存依赖的设计特别符合当时对抗专业矿机的设计，成为数字货币算法发展的一个主要应用方向。
-
论文：Percival, Colin. "Stronger key derivation via sequential memory-hard functions." Self-published (2009): 1-16.
-
应用：Litecoin(LTC)、Dogecoin(DOGE)、DNotes(NOTE)、Florin(FLO)、Gulden(NLG)、DGB-Scrypt(DGB)、GameCredits(GAME)、Verge-Scrypt(XVG)、Einsteinium(EMC2)、AUR-Scrypt(AUR)
-
算法实现：
``` java
public class ScryptDemo
{
public static void main(String[] args) {
String originalPassword = "passw0rd";
String generatedSecuredPasswordHash = SCryptUtil.scrypt(originalPassword, 16, 16, 16);
System.out.println(generatedSecuredPasswordHash);boolean matched = SCryptUtil.check("password", generatedSecuredPasswordHash); System.out.println(matched); matched = SCryptUtil.check("passwordno", generatedSecuredPasswordHash); System.out.println(matched); }}
// Copyright (C) 2011 - Will Glozer. All rights reserved.
package com.lambdaworks.crypto;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.SecureRandom;import static com.lambdaworks.codec.Base64.*;
/**
* Simple {@link SCrypt} interface for hashing passwords using the
* scrypt key derivation function
* and comparing a plain text password to a hashed one. The hashed output is an
* extended implementation of the Modular Crypt Format that also includes the scrypt
* algorithm parameters.
*
* Format: $s0$PARAMS$SALT$KEY.
*
*- PARAMS
32-bit hex integer containing log2(N) (16 bits), r (8 bits), and p (8 bits) - SALT
base64-encoded salt - KEY
base64-encoded derived key - *
- s0 identifies version 0 of the scrypt format, using a 128-bit salt and 256-bit derived key.
* -
@author Will Glozer
/
public class SCryptUtil {
/*- Hash the supplied plaintext password and generate output in the format described
- in {@link SCryptUtil}.
* - @param passwd Password.
- @param N CPU cost parameter.
- @param r Memory cost parameter.
- @param p Parallelization parameter.
* - @return The hashed password.
*/
public static String scrypt(String passwd, int N, int r, int p) {
try {
byte[] salt = new byte[16];
SecureRandom.getInstance("SHA1PRNG").nextBytes(salt);byte[] derived = SCrypt.scrypt(passwd.getBytes("UTF-8"), salt, N, r, p, 32); String params = Long.toString(log2(N) << 16L | r << 8 | p, 16); StringBuilder sb = new StringBuilder((salt.length + derived.length) * 2); sb.append("$s0$").append(params).append('$'); sb.append(encode(salt)).append('$'); sb.append(encode(derived)); return sb.toString();} catch (UnsupportedEncodingException e) {
throw new IllegalStateException("JVM doesn't support UTF-8?");
} catch (GeneralSecurityException e) {
throw new IllegalStateException("JVM doesn't support SHA1PRNG or HMAC_SHA256?");
}
}
/*
* Compare the supplied plaintext password to a hashed password.
*
* @param passwd Plaintext password.
* @param hashed scrypt hashed password.
*
* @return true if passwd matches hashed value.
/
public static boolean check(String passwd, String hashed) {
try {
String[] parts = hashed.split("\$");if (parts.length != 5 || !parts[1].equals("s0")) { throw new IllegalArgumentException("Invalid hashed value"); } long params = Long.parseLong(parts[2], 16); byte[] salt = decode(parts[3].toCharArray()); byte[] derived0 = decode(parts[4].toCharArray()); int N = (int) Math.pow(2, params >> 16 & 0xffff); int r = (int) params >> 8 & 0xff; int p = (int) params & 0xff; byte[] derived1 = SCrypt.scrypt(passwd.getBytes("UTF-8"), salt, N, r, p, 32); if (derived0.length != derived1.length) return false; int result = 0; for (int i = 0; i < derived0.length; i++) { result |= derived0[i] ^ derived1[i]; } return result == 0; } catch (UnsupportedEncodingException e) { throw new IllegalStateException("JVM doesn't support UTF-8?"); } catch (GeneralSecurityException e) { throw new IllegalStateException("JVM doesn't support SHA1PRNG or HMAC_SHA256?"); }}
private static int log2(int n) {
int log = 0;
if ((n & 0xffff0000 ) != 0) { n >>>= 16; log = 16; }
if (n >= 256) { n >>>= 8; log += 8; }
if (n >= 16 ) { n >>>= 4; log += 4; }
if (n >= 4 ) { n >>>= 2; log += 2; }
return log + (n >>> 1);
}
}
```
- PARAMS
