可认证的DH密钥交换协议，供大家参考，具体内容如下

一、实验目的

通过使用密码学库实现可认证的DH密钥交换协议（简化STS协议），能够编写简单的实验代码进行正确的协议实现和验证。

二、实验要求

1、熟悉DH密钥交换算法基本原理；
2、理解原始DH密钥交换算法存在的中间人攻击；
3、理解简化STS协议抗中间人攻击的原理。
4、掌握使用java编写实验代码进行正确的简化STS协议实现和验证。

三、 开发环境

JDK 1.7，Java开发环境（本实验采用Windows+eclipse作为实验环境），要求参与实验的同学按照对称加密提供的方法，提前安装好JDK。

四、实验原理

通过使用密码学库实现可认证的DH密钥交换协议（简化STS协议），能够编写简单的实验代码进行正确的协议实现和验证。

代码段：

AuthDHKeyAgree

import java.math.BigInteger;import java.util.Random;public class AuthDHKeyAgree { private static final int securityParam = 1023; public static BigInteger p; public static BigInteger q; public static BigInteger g; //生成安全素数p,p=2q+1,q为一个1023 bits的大素数 public static void safePGen() { BigInteger one = new BigInteger("1",10); BigInteger two = new BigInteger("2",10); do { p = new BigInteger("0",10); q = new BigInteger(securityParam, 100, new Random()); p = p.add(q.multiply(two).add(one)); }while( p.isProbablePrime(100) == false ); } //选取随机生成元g,通过随机选择[2,p-2]之间的数g,然后判断g^q mod p是否等于1,如果不等于1,则g为生成元 public static void generatorGGen() { BigInteger one = new BigInteger("1",10); BigInteger two = new BigInteger("2",10); BigInteger result; do { g = new BigInteger(securityParam, new Random()); g = g.mod(p.subtract(one)); result = g.modPow(q, p); }while( g.compareTo(two) < 0 || result.compareTo(one) == 0 ); } public static void main(String[] args) { System.out.println("系统初始化,生成安全素数p,选取随机生成元g..."); safePGen(); System.out.println("p: "+p.toString(16)); System.out.println("q: "+q.toString(16)); generatorGGen(); System.out.println("g: "+g.toString(16)); //Alice选择随机秘密值 0<=r1<=p-1 BigInteger r1 = new BigInteger(securityParam, new Random()); BigInteger A; r1 = r1.mod(p); //Alice计算g^r1 mod p A = g.modPow(r1, p); //Bob选择随机秘密值0<=r2<=p-1 BigInteger r2 = new BigInteger(securityParam, new Random()); BigInteger B; //Bob计算g^r2 mod p B = g.modPow(r2, p); //Bob初始化一个RSA签名算法对象 RSASignatureAlgorithm BobRSA = new RSASignatureAlgorithm(); BobRSA.initKeys(); byte[] BobM = (A.toString()+B.toString()+"Alice"+"Bob").getBytes(); //Bob生成签名 BigInteger BobSig = BobRSA.signature(BobM); //Alice验证签名 BobM = (A.toString()+B.toString()+"Alice"+"Bob").getBytes(); boolean result = BobRSA.verify(BobM, BobSig); if( result == true ) System.out.println("Alice验证签名通过。"); else System.out.println("Alice验证签名不通过。"); //Alice计算会话密钥 BigInteger sessionKey = (A.multiply(B)).mod(p); System.out.println("Alice计算得到的会话密钥为:"+sessionKey.toString(16)); //Alice初始化一个RSA签名算法对象 RSASignatureAlgorithm AliceRSA = new RSASignatureAlgorithm(); AliceRSA.initKeys(); byte[] AliceM = (A.toString()+B.toString()+"Alice"+"Bob").getBytes(); //Alice生成签名 BigInteger AliceSig = AliceRSA.signature(AliceM); //Bob验证签名 AliceM = (A.toString()+B.toString()+"Alice"+"Bob").getBytes(); result = AliceRSA.verify(AliceM, AliceSig); if ( result == true ) System.out.println("Bob验证签名通过。"); else System.out.println("Bob验证签名不通过"); //Bob计算会话密钥 sessionKey = (B.multiply(A)).mod(p); System.out.println("Bob计算得到的会话密钥为:"+sessionKey.toString(16)); }}

RSASignatureAlgorithm

import java.math.BigInteger;import java.math.BigInteger;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;import java.util.Random;public class RSASignatureAlgorithm { BigInteger n; BigInteger e; BigInteger d; public BigInteger __hash(byte m[]) { MessageDigest md; try { md = MessageDigest.getInstance("SHA-256"); md.update(m); byte b[] = new byte[33]; System.arraycopy(md.digest(), 0, b, 1, 32); return new BigInteger(b); } catch (NoSuchAlgorithmException e) { System.out.println("this cannot happen."); } return null; } public void initKeys() { BigInteger p = new BigInteger(1024, 500, new Random()); BigInteger q = new BigInteger(1024, 500, new Random()); assert(p.compareTo(q) != 0); n = p.multiply(q); BigInteger fi_n = p.subtract(BigInteger.ONE) .multiply(q.subtract(BigInteger.ONE)); e = new BigInteger(512, 100, new Random()); d = e.modInverse(fi_n); System.out.println("n : " + n.toString(16)); System.out.println("e : " + e.toString(16)); System.out.println("d : " + d.toString(16)); } public BigInteger signature(byte m[]) { BigInteger s = __hash(m).modPow(d, n); System.out.println("s : " + s); return s; } public boolean verify(byte m[], BigInteger s) { BigInteger left = __hash(m).mod(n); BigInteger right = s.modPow(e, n); return left.compareTo(right) == 0; }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。