JAVA RSA 数字签名

import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;

public class GenerateKeyPair {

	private String priKey;
	private String pubKey;

	public void run() {
		try {
			java.security.KeyPairGenerator keygen = java.security.KeyPairGenerator
					.getInstance("RSA");
			SecureRandom secrand = new SecureRandom();
			secrand.setSeed("java".getBytes()); // 初始化随机产生器
			keygen.initialize(1024, secrand);
			KeyPair keys = keygen.genKeyPair();

			PublicKey pubkey = keys.getPublic();
			PrivateKey prikey = keys.getPrivate();

			pubKey = bytesToHexStr(pubkey.getEncoded());
			priKey = bytesToHexStr(prikey.getEncoded());

			System.out.println("pubKey=" + pubKey);
			System.out.println("priKey=" + priKey);

			System.out.println("写入对象 pubkeys ok");
			System.out.println("生成密钥对成功");
		} catch (java.lang.Exception e) {
			e.printStackTrace();
			System.out.println("生成密钥对失败");
		}
		;

	}

	/**
	 * Transform the specified byte into a Hex String form.
	 */
	public static final String bytesToHexStr(byte[] bcd) {
		StringBuffer s = new StringBuffer(bcd.length * 2);

		for (int i = 0; i < bcd.length; i++) {
			s.append(bcdLookup[(bcd[i] >>> 4) & 0x0f]);
			s.append(bcdLookup[bcd[i] & 0x0f]);
		}

		return s.toString();
	}

	/**
	 * Transform the specified Hex String into a byte array.
	 */
	public static final byte[] hexStrToBytes(String s) {
		byte[] bytes;

		bytes = new byte[s.length() / 2];

		for (int i = 0; i < bytes.length; i++) {
			bytes[i] = (byte) Integer.parseInt(s.substring(2 * i, 2 * i + 2),
					16);
		}

		return bytes;
	}

	private static final char[] bcdLookup = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘,
			‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		GenerateKeyPair n = new GenerateKeyPair();
		n.run();
	}
}

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;

public class SignatureData {

	public void run() {
		try {
			String prikeyvalue = "123";// 这是GenerateKeyPair输出的私钥编码
			PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(
					hexStrToBytes(prikeyvalue));
			KeyFactory keyf = KeyFactory.getInstance("RSA");
			PrivateKey myprikey = keyf.generatePrivate(priPKCS8);

			String myinfo = String.valueOf(Math.random()); // 要签名的信息
			// 用私钥对信息生成数字签名
			java.security.Signature signet = java.security.Signature
					.getInstance("MD5withRSA");
			signet.initSign(myprikey);
			signet.update(myinfo.getBytes("ISO-8859-1"));
			byte[] signed = signet.sign(); // 对信息的数字签名

			System.out.println("signed(签名内容)=" + bytesToHexStr(signed));
			System.out.println("info（原值）=" + myinfo);

			System.out.println("签名并生成文件成功");
		} catch (java.lang.Exception e) {
			e.printStackTrace();
			System.out.println("签名并生成文件失败");
		}
		;

	}

	/**
	 * Transform the specified byte into a Hex String form.
	 */
	public static final String bytesToHexStr(byte[] bcd) {
		StringBuffer s = new StringBuffer(bcd.length * 2);

		for (int i = 0; i < bcd.length; i++) {
			s.append(bcdLookup[(bcd[i] >>> 4) & 0x0f]);
			s.append(bcdLookup[bcd[i] & 0x0f]);
		}

		return s.toString();
	}

	/**
	 * Transform the specified Hex String into a byte array.
	 */
	public static final byte[] hexStrToBytes(String s) {
		byte[] bytes;

		bytes = new byte[s.length() / 2];

		for (int i = 0; i < bytes.length; i++) {
			bytes[i] = (byte) Integer.parseInt(s.substring(2 * i, 2 * i + 2),
					16);
		}

		return bytes;
	}

	private static final char[] bcdLookup = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘,
			‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SignatureData s = new SignatureData();
		s.run();

	}
}

import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;
public class VerifySignature {
	public static void main(String[] args) {
		new VerifySignature().run1();
	}
	
	public void run1() {
		try {
			String pubkeyvalue = "30819f300d0609";// 这是GenerateKeyPair输出的公钥编码
			X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(
					hexStrToBytes(pubkeyvalue));
			KeyFactory keyFactory = KeyFactory.getInstance("RSA");
			PublicKey pubKey = keyFactory.generatePublic(bobPubKeySpec);

			//String info = "";
			byte[] signed = hexStrToBytes("32323");// 这是SignatureData输出的数字签名
			java.security.Signature signetcheck = java.security.Signature
					.getInstance("MD5withRSA");
			signetcheck.initVerify(pubKey);
			//signetcheck.update(info.getBytes());
			if (signetcheck.verify(signed)) {
				//System.out.println("info=" + info);
				System.out.println("签名正常");
			} else
				System.out.println("非签名正常");
		} catch (java.lang.Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * Transform the specified byte into a Hex String form.
	 */
	public static final String bytesToHexStr(byte[] bcd) {
		StringBuffer s = new StringBuffer(bcd.length * 2);

		for (int i = 0; i < bcd.length; i++) {
			s.append(bcdLookup[(bcd[i] >>> 4) & 0x0f]);
			s.append(bcdLookup[bcd[i] & 0x0f]);
		}

		return s.toString();
	}

	/**
	 * Transform the specified Hex String into a byte array.
	 */
	public static final byte[] hexStrToBytes(String s) {
		byte[] bytes;

		bytes = new byte[s.length() / 2];

		for (int i = 0; i < bytes.length; i++) {
			bytes[i] = (byte) Integer.parseInt(s.substring(2 * i, 2 * i + 2),
					16);
		}

		return bytes;
	}

	private static final char[] bcdLookup = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘,
			‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };
}