Java中使用OpenSSL生成公钥私钥进行数据加解密
当前使用的是Linux系统，已经安装OpenSSL软件包。
一、使用OpenSSL来生成私钥和公钥
1、执行命令openssl version -a 验证机器上已经安装openssl
$ openssl version -a
2、生成私钥
这条命令让openssl随机生成一份私钥，加密长度是1024位。加密长度是指理论上最大允许”被加密的信息“长度的限制，也就是明文的长度限制。随着这个参数的增大（比方说2048），允许的明文长度也会增加，但同时也会造成计算复杂度的极速增长。一般推荐的长度就是2048位。
$ openssl genrsa -out rsa_private_key.pem 2048
运行结果：
生成私钥文件：C:\Users\PC\rsa_private_key.pem，内容都是标准的ASCII字符，开头一行和结尾一行有明显的标记，真正的私钥数据是中间的不规则字符。
-----BEGIN RSA PRIVATE KEY-----
MIIEpAIBAAKCAQEAyF3lqF456UvWSyvj5iP5oS4hIprE1fUqR0hHXMHN48f/4ycj
tAml3MSHHeE0j3cnutI5xh5WlZAKI1GLZwcZeg0WNDFiRP6pAdz32w==
-----END RSA PRIVATE KEY-----
3、根据私钥生成公钥：C:\Users\PC\rsa_public_key.pem
$ openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem
运行结果：
公钥内容：
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAyF3lqF456UvWSyvj5iP5
grP5WGPmTggfh6vo2NLdvAngk62UgAALdvokmM4xFs/qj8bDBQ8R2Wqvl3JsX/rd
-----END PUBLIC KEY-----
注意：此时的私钥还不能直接被使用，需要进行PKCS#8编码：
4、PKCS#8编码：指明输入私钥文件为rsa_private_key.pem，输出私钥文件为pkcs8_rsa_private_key.pem，不采用任何二次加密（-nocrypt）
$ openssl pkcs8 -topk8 -in rsa_private_key.pem -out pkcs8_rsa_private_key.pem -nocrypt
C:\Users\PC\可以看到pkcs8_rsa_private_key.pem文件。
至此：可用的密钥对已经生成好了，私钥使用pkcs8_rsa_private_key.pem，公钥采用rsa_public_key.pem
二、java使用
1、RSAEncrypt.java -- 读取pem文件格式
package io.xjar.util;
import org.apache.commons.codec.binary.Base64;
import sun.misc.BASE64Decoder;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.*;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
public class RSAEncrypt {
/**
* 字节数据转字符串专用集合
*/
private static final char[] HEX_CHAR = {'0', '1', '2', '3', '4', '5', '6',
'7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
private static final String PRIVATE_KEY = "/pkcs8_rsa_private_key.pem";
private static final String PUBLIC_KEY = "/rsa_public_key.pem";
/**
* 随机生成密钥对
*/
public static void genKeyPair(String filePath) {
// KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
KeyPairGenerator keyPairGen = null;
try {
keyPairGen = KeyPairGenerator.getInstance("RSA");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
// 初始化密钥对生成器，密钥大小为96-1024位
keyPairGen.initialize(1024, new SecureRandom());
// 生成一个密钥对，保存在keyPair中
KeyPair keyPair = keyPairGen.generateKeyPair();
// 得到私钥
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
// 得到公钥
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
try {
// 得到公钥字符串
Base64 base64 = new Base64();
String publicKeyString = new String(base64.encode(publicKey.getEncoded()));
// 得到私钥字符串
String privateKeyString = new String(base64.encode(privateKey.getEncoded()));
// 将密钥对写入到文件
FileWriter pubfw = new FileWriter(filePath + PUBLIC_KEY);
FileWriter prifw = new FileWriter(filePath + PRIVATE_KEY);
BufferedWriter pubbw = new BufferedWriter(pubfw);
BufferedWriter pribw = new BufferedWriter(prifw);
pubbw.write(publicKeyString);
pribw.write(privateKeyString);
pubbw.flush();
pubbw.close();
pubfw.close();
pribw.flush();
pribw.close();
prifw.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 从文件中输入流中加载公钥
*
* @param path 公钥输入流
* @throws Exception 加载公钥时产生的异常
*/
public static String loadPublicKeyByFile(String path) throws Exception {
try {
BufferedReader br = new BufferedReader(new FileReader(path
+ PUBLIC_KEY));
String readLine = null;
StringBuilder sb = new StringBuilder();
while ((readLine = br.readLine()) != null) {
if (readLine.charAt(0) == '-') {
continue;
} else {
sb.append(readLine);
sb.append('\r');
}
}
br.close();
return sb.toString();
} catch (IOException e) {
throw new Exception("公钥数据流读取错误");
} catch (NullPointerException e) {
throw new Exception("公钥输入流为空");
}
}
/**
* 从字符串中加载公钥
*
* @param publicKeyStr 公钥数据字符串
* @throws Exception 加载公钥时产生的异常
*/
public static RSAPublicKey loadPublicKeyByStr(String publicKeyStr)
throws Exception {
try {
BASE64Decoder base64 = new BASE64Decoder();
byte[] buffer = base64.decodeBuffer(publicKeyStr);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
return (RSAPublicKey) keyFactory.generatePublic(keySpec);
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此算法");
} catch (InvalidKeySpecException e) {
throw new Exception("公钥非法");
} catch (NullPointerException e) {
throw new Exception("公钥数据为空");
}
}
/**
* 从文件中加载私钥
*
* @param path 私钥文件名
* @return 是否成功
* @throws Exception
*/
public static String loadPrivateKeyByFile(String path) throws Exception {
try {
BufferedReader br = new BufferedReader(new FileReader(path
+ PRIVATE_KEY));
String readLine = null;
StringBuilder sb = new StringBuilder();
while ((readLine = br.readLine()) != null) {
if (readLine.charAt(0) == '-') {
continue;
} else {
sb.append(readLine);
sb.append('\r');
}
}
br.close();
return sb.toString();
} catch (IOException e) {
throw new Exception("私钥数据读取错误");
} catch (NullPointerException e) {
throw new Exception("私钥输入流为空");
}
}
public static RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr)
throws Exception {
try {
BASE64Decoder base64Decoder = new BASE64Decoder();
byte[] buffer = base64Decoder.decodeBuffer(privateKeyStr);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此算法");
} catch (InvalidKeySpecException e) {
throw new Exception("私钥非法");
} catch (NullPointerException e) {
throw new Exception("私钥数据为空");
}
}
/**
* 公钥加密过程
*
* @param publicKey 公钥
* @param plainTextData 明文数据
* @return
* @throws Exception 加密过程中的异常信息
*/
public static byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData)
throws Exception {
if (publicKey == null) {
throw new Exception("加密公钥为空, 请设置");
}
Cipher cipher = null;
try {
// 使用默认RSA
cipher = Cipher.getInstance("RSA");
// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] output = cipher.doFinal(plainTextData);
return output;
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此加密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
} catch (InvalidKeyException e) {
throw new Exception("加密公钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("明文长度非法");
} catch (BadPaddingException e) {
throw new Exception("明文数据已损坏");
}
}
/**
* 私钥加密过程
*
* @param privateKey 私钥
* @param plainTextData 明文数据
* @return
* @throws Exception 加密过程中的异常信息
*/
public static byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData)
throws Exception {
if (privateKey == null) {
throw new Exception("加密私钥为空, 请设置");
}
Cipher cipher = null;
try {
// 使用默认RSA
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] output = cipher.doFinal(plainTextData);
return output;
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此加密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
} catch (InvalidKeyException e) {
throw new Exception("加密私钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("明文长度非法");
} catch (BadPaddingException e) {
throw new Exception("明文数据已损坏");
}
}
/**
* 私钥解密过程
*
* @param privateKey 私钥
* @param cipherData 密文数据
* @return 明文
* @throws Exception 解密过程中的异常信息
*/
public static byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData)
throws Exception {
if (privateKey == null) {
throw new Exception("解密私钥为空, 请设置");
}
Cipher cipher = null;
try {
// 使用默认RSA
cipher = Cipher.getInstance("RSA");
// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] output = cipher.doFinal(cipherData);
return output;
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此解密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
} catch (InvalidKeyException e) {
throw new Exception("解密私钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("密文长度非法");
} catch (BadPaddingException e) {
throw new Exception("密文数据已损坏");
}
}
/**
* 公钥解密过程
*
* @param publicKey 公钥
* @param cipherData 密文数据
* @return 明文
* @throws Exception 解密过程中的异常信息
*/
public static byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData)
throws Exception {
if (publicKey == null) {
throw new Exception("解密公钥为空, 请设置");
}
Cipher cipher = null;
try {
// 使用默认RSA
cipher = Cipher.getInstance("RSA");
// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
cipher.init(Cipher.DECRYPT_MODE, publicKey);
byte[] output = cipher.doFinal(cipherData);
return output;
} catch (NoSuchAlgorithmException e) {
throw new Exception("无此解密算法");
} catch (NoSuchPaddingException e) {
e.printStackTrace();
return null;
} catch (InvalidKeyException e) {
throw new Exception("解密公钥非法,请检查");
} catch (IllegalBlockSizeException e) {
throw new Exception("密文长度非法");
} catch (BadPaddingException e) {
throw new Exception("密文数据已损坏");
}
}
/**
* 字节数据转十六进制字符串
*
* @param data 输入数据
* @return 十六进制内容
*/
public static String byteArrayToString(byte[] data) {
StringBuilder stringBuilder = new StringBuilder();
for (int i = 0; i < data.length; i++) {
// 取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移
stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]);
// 取出字节的低四位 作为索引得到相应的十六进制标识符
stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);
if (i < data.length - 1) {
stringBuilder.append(' ');
}
}
return stringBuilder.toString();
}
2、RSASignature.java -- SHA256withRSA签名
package io.xjar.util;
import java.security.PrivateKey;
import java.security.PublicKey;
public class RSASignature {
/**
* 签名算法
*/
public static final String SIGN_ALGORITHMS = "hwU-gARp25KqMFVxw-9J3eCfRNXSN9QM0,ymavRvG0ByPpWEx-IJ{I0DE3w6LMP0fUwKDmSevTpFf=1Q}-h8B,14UGHs4-{flavC";
/**
* RSA签名
*
* @param content 待签名数据
* @param privateKey 商户私钥
* @param encode 字符集编码
* @return 签名值
*/
public static String sign(String content, PrivateKey privateKey, String encode) {
try {
java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
signature.initSign(privateKey);
signature.update(content.getBytes(encode));
byte[] signed = signature.sign();
return byte2Hex(signed);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static String sign(String content, PrivateKey privateKey) {
try {
java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
signature.initSign(privateKey);
signature.update(content.getBytes());
byte[] signed = signature.sign();
return byte2Hex(signed);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 将byte[] 转换成字符串
*/
public static String byte2Hex(byte[] srcBytes) {
StringBuilder hexRetSB = new StringBuilder();
for (byte b : srcBytes) {
String hexString = Integer.toHexString(0x00ff & b);
hexRetSB.append(hexString.length() == 1 ? 0 : "").append(hexString);
}
return hexRetSB.toString();
}
/**
* RSA验签名检查
*
* @param content 待签名数据
* @param sign 签名值
* @param publicKey 分配给开发商公钥
* @param encode 字符集编码
* @return 布尔值
*/
public static boolean doCheck(String content, String sign, PublicKey publicKey, String encode) {
try {
java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
signature.initVerify(publicKey);
signature.update(content.getBytes(encode));
boolean bverify = signature.verify(hex2Bytes(sign));
return bverify;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
public static boolean doCheck(String content, String sign, PublicKey publicKey) {
try {
java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
signature.initVerify(publicKey);
signature.update(content.getBytes());
boolean bverify = signature.verify(hex2Bytes(sign));
return bverify;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
/**
* 将16进制字符串转为转换成字符串
*/
public static byte[] hex2Bytes(String source) {
byte[] sourceBytes = new byte[source.length() / 2];
for (int i = 0; i < sourceBytes.length; i++) {
sourceBytes[i] = (byte) Integer.parseInt(source.substring(i * 2, i * 2 + 2), 16);
}
return sourceBytes;
}
}
3、ApplicationTests.java -- 测试类
package io.xjar.util;
import org.apache.commons.codec.binary.Base64;
public class ApplicationTests {
public static void main(String[] args) throws Exception {
String publicPath = "C:\\Users\\PC\\Desktop\\jar"; //公匙存放位置
String privatePath = "C:\\Users\\PC"; //私匙存放位置
Base64 base64 = new Base64();
System.out.println("--------------公钥加密私钥解密过程-------------------");
String signKey = "ihep_公钥加密私钥解密";
// 公钥加密过程
byte[] cipherData = RSAEncrypt.encrypt(RSAEncrypt.loadPublicKeyByStr(RSAEncrypt.loadPublicKeyByFile(publicPath)),
signKey.getBytes());
String cipher = new String(base64.encode(cipherData));
// 私钥解密过程
byte[] res = RSAEncrypt.decrypt(RSAEncrypt.loadPrivateKeyByStr(RSAEncrypt.loadPrivateKeyByFile(privatePath)),
base64.decode(cipher));
String restr = new String(res);
System.out.println("原文：" + signKey);
System.out.println("加密：" + cipher);
System.out.println("解密：" + restr);
System.out.println();
System.out.println("--------------私钥加密公钥解密过程-------------------");
// 私钥加密过程
cipherData = RSAEncrypt.encrypt(RSAEncrypt.loadPrivateKeyByStr(RSAEncrypt.loadPrivateKeyByFile(privatePath)), signKey.getBytes());
cipher = new String(base64.encode(cipherData));
// 公钥解密过程
res = RSAEncrypt.decrypt(RSAEncrypt.loadPublicKeyByStr(RSAEncrypt.loadPublicKeyByFile(publicPath)), base64.decode(cipher));
restr = new String(res);
System.out.println("原文：" + signKey);
System.out.println("加密：" + cipher);
System.out.println("解密：" + restr);
System.out.println();
}
}
执行返回结果：
--------------公钥加密私钥解密过程-------------------
原文：ihep_公钥加密私钥解密
加密：NoHUCeWh89dww+zcWT4+iLFlg/oJb1N7SqahbOsNCfE+F/7PZQ/tnRFaQ+TKEXpsZORQ+w0Zix40BJayWInU9jdXKc6zgafChnj/W5NHrAYNWskMGPTGzon1TBmae8V9E+EgZs7VAi2qLYSxGeczMGN8Ak08qpziGQpJp/ciStf76VkhTjSSb/4RpyxhgsJAyzTRv45traXaSj3IHP0zwYYD8gfXb3Yla/x95Ypys8/E3fggronXG6q98J+1sSF1U/4baWk/nx0s3/al60HnImWlJFCus9zz684g4iyn5PsEoRz1gpyjavXvK9cfGdPkPbitlcbMEMdQHV7cMOr1XQ==
解密：ihep_公钥加密私钥解密
--------------私钥加密公钥解密过程-------------------
原文：ihep_公钥加密私钥解密
加密：v3Y+8RDZMFTnHyMgBsBr2jqvYosqymuhY+CJESF6kPNyanYBaay0Hp++C7iHAnPs3QBTXQZVdUrd4X9dCW0TvO94t5uCM9C5hIZQa1dqhv//i5O3fK6YUfFBR8UcnGXa6OlHz3WCBdEiG/xgpKlix4e99Yk5oJVVGu+TmcsaxbrTZMSFMkKx2SQvF5AiVZWCMV4ZIqPyBe+DOtiQBDPQs8ruExVbM+L5m+3M6bWeWzlmQnwDBqxFgFdbfVqnB4hrXQwUqt4DgPTiuIlQmEpQGjTr+p+bFkxtR0itt8Bba+XBLR9uiDsQ7q4MMRZnJk0/c5e1ek15rQyAqAJKZrvdWA==
解密：ihep_公钥加密私钥解密
