java的非对称性加密服务技术分析.doc

java的非对称性加密服务技术分析鉴于rsa加密的重要性与拖累源代码的匮乏，经过整顿特此贴出。需要下载bcprov-jdk14-123.jar。import javax.crypto.Cipher;import java.security.*;import java.security.spec.RSAPublicKeySpec;import java.security.spec.RSAPrivateKeySpec;import java.security.spec.InvalidKeySpecException;import erfaces.RSAPrivateKey;import erfaces.RSAPublicKey;import java.io.*;import java.math.BigInteger;/* RSA 东西类。供给加密，解密，天生密钥平匀办法。* 需要到下载bcprov-jdk14-123.jar。*/public class RSAUtil /* 天生密钥对* return KeyPair* throws EncryptException*/public static KeyPair generateKeyPair() throws EncryptException try KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(RSA,new vider.BouncyCastleProvider();final int KEY_SIZE = 1024;/没什么好说的了，这个值相干到块加密的大小，可以变幻，然而不要太大，不然服从会低keyPairGen.initialize(KEY_SIZE, new SecureRandom();KeyPair keyPair = keyPairGen.genKeyPair();return keyPair; catch (Exception e) throw new EncryptException(e.getMessage();/* 天生公钥* param modulus* param publicExponent* return RSAPublicKey* throws EncryptException*/public static RSAPublicKey generateRSAPublicKey(byte modulus, byte publicExponent) throws EncryptException KeyFactory keyFac = null;try keyFac = KeyFactory.getInstance(RSA, new vider.BouncyCastleProvider(); catch (NoSuchAlgorithmException ex) throw new EncryptException(ex.getMessage();RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(modulus), new BigInteger(publicExponent);try return (RSAPublicKey) keyFac.generatePublic(pubKeySpec); catch (InvalidKeySpecException ex) throw new EncryptException(ex.getMessage();/* 天生私钥* param modulus* param privateExponent* return RSAPrivateKey* throws EncryptException*/public static RSAPrivateKey generateRSAPrivateKey(byte modulus, byte privateExponent) throws EncryptException KeyFactory keyFac = null;try keyFac = KeyFactory.getInstance(RSA, new vider.BouncyCastleProvider(); catch (NoSuchAlgorithmException ex) throw new EncryptException(ex.getMessage();RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(modulus), new BigInteger(privateExponent);try return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec); catch (InvalidKeySpecException ex) throw new EncryptException(ex.getMessage();/* 加密* param key 加密的密钥* param data 待加密的明文数据* return 加密后的数据* throws EncryptException*/public static byte encrypt(Key key, byte data) throws EncryptException try Cipher cipher = Cipher.getInstance(RSA, new vider.BouncyCastleProvider();cipher.init(Cipher.ENCRYPT_MODE, key);int blockSize = cipher.getBlockSize();/失掉加密块大小，如:加密前数据为128个byte，而key_size=1024 加密块大小为127 byte,加密后为128个byte;于是共有2个加密块，第一个127 byte第二个为1个byteint outputSize = cipher.getOutputSize(data.length);/失掉加密块加密后块大小int leavedSize = data.length % blockSize;int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize;byte raw = new byteoutputSize * blocksSize;int i = 0;while (data.length - i * blockSize 0) if (data.length - i * blockSize blockSize)cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize);elsecipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize);/这内中doUpdate办法不可用，查抄源代码后缔造每次doUpdate后并无什么实际行动除了把byte放到ByteArrayOutputStream中，而末了doFinal的时分才将全体的byte发展加密，然而到了此时加密块大小极梗概已经超出了OutputSize所以只好用dofinal办法。i+;return raw; catch (Exception e) throw new EncryptException(e.getMessage();/* 解密* param key 解密的密钥* param raw 已经加密的数据* return 解密后的明文* throws EncryptException*/public static byte decrypt(Key key, byte raw) throws EncryptException try Cipher cipher = Cipher.getInstance(RSA, new vider.BouncyCastleProvider();cipher.init(cipher.DECRYPT_MODE, key);int blockSize = cipher.getBlockSize();ByteArrayOutputStream bout = new ByteArrayOutputStream(64);int j = 0;while (raw.length - j * blockSize 0) bout.write(cipher.doFinal(raw, j * blockSize, blockSize);j+;return bout.toByteArray(); catch (Exception e) throw new EncryptException(e.getMessage();/* param args* throws Exception*/public static void main(String args) throws Exception File file = new File(test.html);FileInputStream in = new FileInputStream(file);ByteArrayOutputStream bout = new ByteArrayOutputStream();byte tmpbuf = new byte1024;int count = 0;while (count = in.read(tmpbuf) != -1) bout.write(tmpbuf, 0, count);tmpbuf = new byte1024;in.close();byte orgData = bout.toByteArray();KeyPair keyPair = RSAUtil.generateKeyPair();RSAPublicKey pubKey = (RSAPublicKey) keyPair.getPublic();RSAPrivateKey priKey = (RSAPrivateKey) keyPair.getPrivate();byte pubModBytes = pubKey.getModulus().toByteArray();byte pubPubExpBytes = pubKey.getPublicExponent().toByteArray();byte priModBytes = priKey.getModulus().toByteArray();byte priPriExpBytes = priKey.getPrivateExponent().toByteArray();RSAPublicKey recoveryPubKey = RSAUtil.generateRSAPublicKey(pubModBytes,pubPubExpBytes);RSAPrivateKey recoveryPriKey = RSAUtil.generateRSAPrivateKey(priModBytes,priPriExpBytes);byte raw = RSAUtil.encrypt(priKey, orgData);file = new File(encrypt_result.dat);OutputStream out = new FileOutputStream(file);out.write(raw);out.close();byte data = RSAUtil.decrypt(