RSA加密

今天终于理解了Java使用RSA算法的原理和步骤
基本方法就是生成KeyPair
然后通过encoder 再base64 变成byte数据
然后在传输后进行反向操作

在实验的 过程中也发现了其中密钥生成和加密的过程比较费时，如果考虑到大量的用户同时操作可能会导致系统性能不足以支持，另外，较长的处理信息时间要求有更好的并发性能，可以采用类似线程池的方法来进行并发操作，如果不改变当前算法，可以通过将加密这一过程分布到多台计算机上进行运算，可以有效的避免这一瓶颈，按照这样的伸缩性要求，加密和解密模块可以进行进一步分离，预留接口以备分布式操作。

性能数据：
slevenc@linux-7vvc:/my/projects/IMYOURS/rsaTest/bin> java RsaTest
初始化
18
生成密钥
653
加密文本
466
message sth阿斯顿会计法片尾urqpeqwpeiurqwpeurwqpeirupwqeiurpwioeurpoqwieurpowqeirupoqweirupqoweirupoqweirup
解密文本
24
slevenc@linux-7vvc:/my/projects/IMYOURS/rsaTest/bin> java RsaTest
初始化
17
生成密钥
506
加密文本
582
message sth阿斯顿会计法片尾urqpeqwpeiurqwpeurwqpeirupwqeiurpwioeurpoqwieurpowqeirupoqweirupqoweirupoqweirup
解密文本
36

相关代码：

public static void main(String args[]) {
		String text = "message sth阿斯顿会计法片尾urqpeqwpeiurqwpeurwqpeirupwqeiurpwioeurpoqwieurpowqeirupoqweirupqoweirupoqweirup";
		Date d = new Date();

		try {
			KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
			kpg.initialize(1024);

			System.out.println("初始化");
			System.out.println((new Date()).getTime() - d.getTime());
			d = new Date();

			KeyPair kp = kpg.generateKeyPair();
			
			
			System.out.println("生成密钥");
			System.out.println((new Date()).getTime() - d.getTime());
			d = new Date();

//			System.out.println("public:\n" + getKey(kp.getPublic()));
//			System.out.println("private:\n" + getKey(kp.getPrivate()));
//			
//			System.out.println("屏幕打印");
//			System.out.println((new Date()).getTime() - d.getTime());
//			d = new Date();
			
			byte[] eb = EncoderByPublicKey(text,getKey(kp.getPublic()));
			
			
			System.out.println("加密文本");
			System.out.println((new Date()).getTime() - d.getTime());
			d = new Date();
			
			System.out.println(DecoderByPrivateKey(eb,getKey(kp.getPrivate())));
			
			System.out.println("解密文本");
			System.out.println((new Date()).getTime() - d.getTime());
			d = new Date();
			
			

		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	
	private static byte[] EncoderByPublicKey(String text,String key)throws Exception{
		byte[] keyBytes = (new BASE64Decoder()).decodeBuffer(key);
		
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key publicKey = keyFactory.generatePublic(x509KeySpec);
		
		
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);
		
		return cipher.doFinal(text.getBytes("utf-8"));
			
		
	}
	
	
	private static String DecoderByPrivateKey(byte[] data,String key)throws Exception{
		
		byte[] keyBytes = (new BASE64Decoder()).decodeBuffer(key);
		
		PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance("RSA");
		Key privateKey = keyFactory.generatePrivate(keySpec);
		
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateKey);
		
		return new String(cipher.doFinal(data),"utf-8");
		
		
		
	}

	private static String getKey(Key key) {
		return (new BASE64Encoder()).encode(key.getEncoded());

	}

评论

1 楼 364902709 2011-05-18  

超过117字节怎么处理？