rsaalgo.java

非常完整的rsa加密解密软件 有多完整？自己看吧

/******************************************************
 *COPYRIGHT@author YIMINGHE , 创建日期 : 2005-12-11
 *
 *         @FUDAN UNIVERSITY
 *
 *Email : [e-mail],[e-mail]
 *
 *MSN   : [e-mail] 
 *
 *TODO
 ******************************************************/

package algo;

import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.StringTokenizer;

import tool.BinaryInteger;

/**
 * rsa加密算法 注意： 1:rsa的位数一定要比加密的数据位数大??!! 2:对中文支持不太好，原因不明，会出现乱码
 * 
 * @author YiMingHe
 * 
 */
public class RsaAlgo {
	/**
	 * p1,p2为随机的两个大素数 n1=p1*p2,为公匙 fn1=(p1-1)*(p2-1) d1为随机选取满足(d1,fn1)=1，为密匙
	 * e1满足 e1*d1 mod fn1= 1 ，为公匙 plaintext为密文 ciphertext为明文
	 */
	private BinaryInteger prime1 = null, prime2 = null, n1 = null, fn1 = null,
			d1 = null, e1 = null, plaintext = null, ciphertext = null;

	private int bitlength = 512 / 2;

	private int block = 512;

	// 加密
	public static final int ENCRYPT = 1;

	// 解密
	public static final int DECRYPT = 2;

	// 随机数
	private final static SecureRandom random = new SecureRandom();

	/**
	 * 构造函数，得到指定位数的密匙
	 * 
	 * @param bits,所需素数的位数
	 */
	public RsaAlgo(int bits) {
		this.bitlength = bits/2;
		setCipher();
	}

	/**
	 * 专为加密解密构造，rsa
	 * 
	 * @param n
	 * @param ed
	 * @param type，
	 */
	public RsaAlgo(String n, String ed, int type) {

		n1 = new BinaryInteger(n, 10);
		if (type == RsaAlgo.ENCRYPT) {
			e1 = new BinaryInteger(ed, 10);
		} else if (type == RsaAlgo.DECRYPT) {
			d1 = new BinaryInteger(ed, 10);
		}

	}

	/**
	 * 产生公匙密匙
	 * 
	 */

	private void setCipher() {

		prime1 = BinaryInteger.probablePrime(bitlength, random);
		prime2 = BinaryInteger.probablePrime(bitlength, random);
		// 产生公匙n1
		n1 = prime1.multiply(prime2);
		fn1 = (prime1.subtract(BinaryInteger.ONE)).multiply(prime2
				.subtract(BinaryInteger.ONE));

		// 产生密匙
		while (true) {

			d1 = new BinaryInteger(bitlength, random);
			// d1 = BinaryInteger.probablePrime(bitlength, random);
			// if (fn1.gcd(d1).intValue() ==
			// 1&&d1.compareTo(n1)==-1&&d1.compareTo(prime1.max(prime2))!=-1)
			if (fn1.gcd(d1).intValue() == 1)
				break;
		}

		// 产生公匙e1
		e1 = d1.modInverse(fn1);

	}

	/**
	 * 得到公匙
	 * 
	 * @return，第一个为n1,第二个为e1
	 */
	public BinaryInteger[] getPublicCiphers() {
		BinaryInteger[] publiciphers = new BinaryInteger[2];
		publiciphers[0] = n1;
		publiciphers[1] = e1;
		return publiciphers;

	}

	/**
	 * 得到密匙
	 * 
	 * @return d1，密匙
	 */
	public BinaryInteger getPrivateCipher() {
		return d1;
	}

	/**
	 * 用于加密时设置
	 * 
	 * @param n
	 * @param e
	 */

	public void setEncryptCiphers(String n, String e) {

		n1 = new BinaryInteger(n, 10);
		e1 = new BinaryInteger(e, 10);
	}

	/**
	 * 用于解密是设置
	 * 
	 * @param n
	 * @param d
	 */
	public void setDecryptCiphers(String n, String d) {

		n1 = new BinaryInteger(n, 10);
		d1 = new BinaryInteger(d, 10);
	}

	/**
	 * 
	 * @param plain，名文
	 * @param n1，公匙
	 * @param e1，公匙
	 * @return，加密后的byte数组
	 */
	public String encrypt(String bplain) {

		// if (bitlength < bplain.length()*2*8)
		// throw new Exception("注意：rsa的位数一定要比加密的数据位数大??!!");
		BinaryInteger plain = new BinaryInteger(bplain.getBytes());
		return new String(plain.modPow(e1, n1).toString(10));

	}

	/**
	 * 
	 * @param ciphertext，密文
	 * @param n1,公匙
	 * @param d1，密匙
	 * @return，返回解密后的byte[]数组
	 */

	public String decrypt(String sciphertext) {

		BinaryInteger ciphertext = new BinaryInteger(sciphertext, 10);

		return new String(ciphertext.modPow(d1, n1).toByteArray());

	}

	/**
	 * 大量文本的分段加密
	 * 
	 * @param s
	 *            ,大量明文
	 * @return ,加密后密文，密文端之间以空格隔开
	 */
	public String largeEncrypt(String s) {
		int strsize = block / 8 / 4;
		String result = "";

		for (int i = 0; i < s.length(); i += strsize) {
			String part = "";
			if (i + strsize < s.length())
				part = s.substring(i, i + strsize);
			else
				part = s.substring(i);
			result += encrypt(part) + "\n";
		}

		return result;
	}

	/**
	 * 密文的分段解密
	 * 
	 * @param s
	 *            ，以空格隔开的密文端
	 * @return，明文
	 */
	public String largeDecrypt(String s) {
		StringTokenizer token = new StringTokenizer(s);
		String result = "";
		while (token.hasMoreTokens()) {
			result += decrypt(token.nextToken());
		}
		return result;
	}

	/**
	 * byte[] c=c1+c2
	 * 
	 * @param c1
	 * @param c2
	 * @return
	 */
	public static byte[] connect(byte[] c1, byte[] c2) {
		byte[] c = new byte[c1.length + c2.length];
		int index = 0;
		for (int i = 0; i < c1.length; i++)
			c[index++] = c1[i];
		for (int i = 0; i < c2.length; i++)
			c[index++] = c2[i];

		return c;
	}

	public static void main(String[] argv) {
		// !rsa的位数一定要比加密数据的位数大!!??

		String test = "134568796中国1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf1354sdfsadf";
		ArrayList store = new ArrayList();

		// rsa的位数
		int block = 512;

		// 每16个unicode字符加密一次
		int strsize = block / 8 / 4;

		RsaAlgo rsa = new RsaAlgo(block);

		/*
		 * for(int i=0;i<test.length();i+=strsize) { String part="";
		 * if(i+strsize<test.length()) part=test.substring(i,i+strsize); else
		 * part=test.substring(i); String re=rsa.encrypt(part); store.add(re); }
		 * 
		 * for(int i=0;i<store.size();i++)
		 * System.out.println((String)store.get(i));
		 * 
		 * for(int i=0;i<store.size();i++) {
		 * System.out.print(rsa.decrypt((String)store.get(i))); }
		 */
		String e = rsa.largeEncrypt(test);
		System.out.println(e);
		System.out.println(rsa.largeDecrypt(e));

	}

}