本文目录一览：
- 1、怎样用Java实现RSA加密
- 2、JAVA写RSA加密，公钥私钥都是一样的，为什么每次加密的结果不一样
- 3、Java中RSA的方式如何实现非对称加密的示例
- 4、java rsa加密，高并发如何解决
怎样用Java实现RSA加密
提供加密，解密，生成密钥对等方法。�梢愿�模��遣灰��螅�裨蛐�驶岬� keyPairGen.initialize(KEY_SIZE, new SecureRandom()); KeyPair keyPair = keyPairGen.genKeyPair(); return keyPair; } catch (Exception e) { throw new Exception(e.getMessage()); } } /** * 生成公钥 * @param modulus * @param publicExponent * @return RSAPublicKey * @throws Exception */ public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(modulus), new BigInteger(publicExponent)); try { return (RSAPublicKey) keyFac.generatePublic(pubKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(ex.getMessage()); } } /** * 生成私钥 * @param modulus * @param privateExponent * @return RSAPrivateKey * @throws Exception */ public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(modulus), new BigInteger(privateExponent)); try { return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(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 Exception */ public static byte[] encrypt(Key key, byte[] data) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, key); int blockSize = cipher.getBlockSize();//获得加密块大小� i++; } return raw; } catch (Exception e) { throw new Exception(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 Exception */ public static byte[] decrypt(Key key, byte[] raw) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.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 Exception(e.getMessage()); } } /** * * @param args * @throws Exception */ public static void main(String[] args) throws Exception { File file = new File("c:/test.html"); FileInputStream in = new FileInputStream(file); ByteArrayOutputStream bout = new ByteArrayOutputStream(); byte[] tmpbuf = new byte[1024]; int count = 0; while ((count = in.read(tmpbuf)) != -1) { bout.write(tmpbuf, 0, count); tmpbuf = new byte[1024]; } in.close(); byte[] orgData = bout.toByteArray(); KeyPair keyPair = RSA.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 = RSA.generateRSAPublicKey(pubModBytes,pubPubExpBytes); RSAPrivateKey recoveryPriKey = RSA.generateRSAPrivateKey(priModBytes,priPriExpBytes); byte[] raw = RSA.encrypt(priKey, orgData); file = new File("c:/encrypt_result.dat"); OutputStream out = new FileOutputStream(file); out.write(raw); out.close(); byte[] data = RSA.decrypt(recoveryPubKey, raw); file = new File("c:/decrypt_result.html"); out = new FileOutputStream(file); out.write(data); out.flush(); out.close(); } } （责任编辑：云子）
JAVA写RSA加密，公钥私钥都是一样的，为什么每次加密的结果不一样
因为rsa是非对称加密，它使用的是随机大素数的抽取，每次随机生成的，所以每次加密的结果不可能一样
Java中RSA的方式如何实现非对称加密的示例
代码如下，需要依赖一个jar包commons-codec-1.9.jar，用于Base64转换，请自行下载。
import org.apache.commons.codec.binary.Base64;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
public class RSAUtils {
// 加密方式
public static final String ALGORITHM = "RSA";
// 签名算法
private static final String SIGNATURE_ALGORITHM = "SHA1WithRSA";
// 创建密钥对初始长度
private static final int KEY_SIZE = 512;
// 字符编码格式
private static final String CHARSET = "UTF-8";
// RSA最大加密明文大小
private static final int MAX_ENCRYPT_BLOCK = 117;
// RSA最大解密密文大小
private static final int MAX_DECRYPT_BLOCK = 128;
private KeyFactory keyFactory;
public RSAUtils() throws NoSuchAlgorithmException {
keyFactory = KeyFactory.getInstance(ALGORITHM);
}
/**
* 私钥加密
*
* @param content 待加密字符串
* @param privateKey 私钥
* @return 加密后字符串（BASE64编码）
*/
public String encryptByPrivateKey(String content, String privateKey) throws Exception {
String result;
try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
byte[] keyBytes = new Base64().decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
PrivateKey pKey = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, pKey);
byte[] data = content.getBytes(CHARSET);
write2Stream(cipher, data, out);
byte[] resultBytes = out.toByteArray();
result = Base64.encodeBase64String(resultBytes);
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 公钥解密
*
* @param content 已加密字符串（BASE64加密）
* @param publicKey 公钥
* @return
*/
public String decryptByPublicKey(String content, String publicKey) throws Exception {
String result = "";
try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
byte[] keyBytes = new Base64().decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
PublicKey pKey = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, pKey);
byte[] data = Base64.decodeBase64(content);
write2Stream(cipher, data, out);
byte[] resultBytes = out.toByteArray();
result = new String(resultBytes);
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 公钥加密
*
* @param content 待加密字符串
* @param publicKey 公钥
* @return 加密后字符串（BASE64编码）
*/
public String encryptByPublicKey(String content, String publicKey) throws Exception {
String result = "";
try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
byte[] keyBytes = new Base64().decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
PublicKey pKey = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, pKey);
byte[] data = content.getBytes(CHARSET);
write2Stream(cipher,
data, out);
byte[] resultBytes = out.toByteArray();
result = Base64.encodeBase64String(resultBytes);
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 私钥解密
*
* @param content 已加密字符串
* @param privateKey 私钥
* @return 解密后字符串
*/
public String decryptByPrivateKey(String content, String privateKey) throws Exception {
String result = "";
try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
byte[] keyBytes = new Base64().decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
PrivateKey pKey = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, pKey);
byte[] data = Base64.decodeBase64(content);
write2Stream(cipher, data, out);
byte[] resultBytes = out.toByteArray();
result = new String(resultBytes);
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
private static void write2Stream(Cipher cipher, byte[] data, ByteArrayOutputStream out) throws
BadPaddingException, IllegalBlockSizeException {
int dataLen = data.length;
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (dataLen - offSet 0) {
if (dataLen - offSet MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, dataLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
}
/**
* 用私钥对信息生成数字签名
*
* @param data 已加密数据
* @param privateKey 私钥(BASE64编码)
* @return sign
*/
public String sign(String data, String privateKey) throws Exception {
String result = "";
try {
byte[] keyBytes = new Base64().decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(parse2HexStr(data).getBytes(CHARSET));
result = new Base64().encodeToString(signature.sign());
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 校验数字签名
*
* @param data 已加密数据
* @param publicKey 公钥(BASE64编码)
* @param sign 数字签名
* @return
* @throws Exception
*/
public boolean verify(String data, String publicKey, String sign) throws Exception {
boolean result;
try {
byte[] keyBytes = new Base64().decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(parse2HexStr(data).getBytes(CHARSET));
result = signature.verify(new Base64().decode(sign));
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 将二进制转换成16进制
*
* @param data
* @return
*/
public static String parse2HexStr(String data) throws Exception {
String result = "";
try {
byte[] buf = data.getBytes(CHARSET);
StringBuffer sb = new StringBuffer();
for (int i = 0; i buf.length; i++) {
String hex = Integer.toHexString(buf[i] 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
result = sb.toString();
} catch (UnsupportedEncodingException e) {
throw new Exception(e);
}
return result;
}
/**
* 生成公钥与私钥
*/
public static void createKey() throws Exception {
try {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
keyPairGenerator.initialize(KEY_SIZE);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
String publicKey = Base64.encodeBase64String(rsaPublicKey.getEncoded());
String privateKey = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
System.out.println("publicKey=" + publicKey + "\nprivateKey=" + privateKey);
} catch (NoSuchAlgorithmException e) {
throw new Exception(e);
}
}
public static void main(String[] args) throws Exception {
String PRIVATE_KEY = "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";
String PUBLIC_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCnmBlx+lc/pviri9dUQ0WjXRweGEHmYKqSRj0UsAXpYLxKB7tv3zbNW5oHyYSPJYa/6Px8vBBQfyPww8i3AnFOGwi7caZIvHnQviiUdlr8mH51ZlhHv96to0lSkX/NfOvKvQndzDH60DzLGOMdE0NBrTn/5zEjGwJbVdlvCfOiHwIDAQAB";
RSAUtils rsaUtil = new RSAUtils();
String encryptByPublicKey = rsaUtil.encryptByPublicKey("你好！", PUBLIC_KEY);
System.out.println(encryptByPublicKey);
String decryptByPrivateKey = rsaUtil.decryptByPrivateKey(encryptByPublicKey, PRIVATE_KEY);
System.out.println(decryptByPrivateKey);
String encryptByPrivateKey = rsaUtil.encryptByPrivateKey("你好！", PRIVATE_KEY);
System.out.println(encryptByPrivateKey);
String decryptByPublicKey = rsaUtil.decryptByPublicKey(encryptByPrivateKey, PUBLIC_KEY);
System.out.println(decryptByPublicKey);
String sign = rsaUtil.sign("1234", PRIVATE_KEY);
System.out.println("sign:" + sign);
System.out.println(rsaUtil.verify("1234", PUBLIC_KEY, sign));
}
}
java rsa加密，高并发如何解决
既然高并发了务必要考虑吞吐量吧，进行同步不是一个好的选择。
其实你可以把加密算法与私钥封装进一个类里，然后每次请求实例化这个类，创建一个实体，之后进行解密就行了。
