RSA2实例详解
包含内容: 源码,全套工具
作者QQ549710689
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RSA文章: http://wisdomdd.cn/Wisdom/resource/articleDetail.htm?resourceId=322
关于RSA2的理论其实与RSA类似，想具体了解的可以参考上面的链接,下面直接上代码
函数test1中使用RSA2的私钥对数据进行加密，使用RSA2的公钥对数据进行解密
下面代码中的密钥字符串是对密钥字节数组进行了base64加密而得到的，在使用时将密串进行base64解密即可
//私钥加密，公钥解密
public static void test1(String src){
try {
//1.初始化密钥
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
//String strPublicKey = Base64.encodeBase64String(rsaPublicKey.getEncoded());
//String strPrivateKey = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
String strPublicKey = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAgdQVFyYvJQ38hBAEJ3Zr3BJFtp
XauN83ghWtgJ1m92XvshGomjEgKpAxyQf9HqqvZB8U0nW+eNIgTAcKZemIQci/6/+oXMhu+WgdIxlJGLzvhZWa
z7UzfKfCFTiUAh6X+hHRlPisekt/y70pbpkxd+GVbmVF5bGxSBnlhdnKa+lAbZd2sO8jv3fzSD0w3dWDmjKg9O
jPxXt1jnwbj0BmwN4TDiMPSmmDBEz7JHadb6A99cswCVXWz3pgioHzq20ipDZDUdAphtgcyT6TO1eZdwHth1tw
0UIcPfUmx5wMGSVBkP/42/AnvG8Y9ROwvg9XpCu2HI+o/n7Ljht5tknDKwIDAQAB";
String strPrivateKey = "MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCB1BUXJi8lDfy
EEAQndmvcEkW2ldq43zeCFa2AnWb3Ze+yEaiaMSAqkDHJB/0eqq9kHxTSdb540iBMBwpl6YhByL/r/6hcyG75aB0j
GUkYvO+FlZrPtTN8p8IVOJQCHpf6EdGU+Kx6S3/LvSlumTF34ZVuZUXlsbFIGeWF2cpr6UBtl3aw7yO/d/NIPTDd1YO
aMqD06M/Fe3WOfBuPQGbA3hMOIw9KaYMETPskdp1voD31yzAJVdbPemCKgfOrbSKkNkNR0CmG2BzJPpM7V5l3Ae2HW3DRQh
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0VO7kbm8jGFPR+Lt2jBR75z8wa77s190H9AE28bicUaSSJ0oQ0RYwMMcPKPkRwRoiM1bngeg4+Rqkp37s9DdTZWie5lkoxk
HRQnNcpLnXy63aSOiQnFbGj+eXDXpwOWXuRm1YdVz2cBm1U71Fy4pKNKU8B/Z/gLucnxotXWVQjhguKIrY0BEdH/0TJlPzl
AQQYYuCItA7gJUNivCv0ecDswG0AchkdAIwbjRFS9Jpc4sWkvlgdYaP33uNjzXQrG7QZxSaCADorB8vFM/c7MxJZuS5hOvI
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dY5yYkTY2gWIgwf1f3HxEOY0ZuydTjrppkBnngGs2L03x2F+ZEnHYrg3DwUdahRxxqI/DyzKOUWUOt48ESaoMLUUFmdTrR7
Bw5inS1WNhirv/XQKBgQCE7TfDTGe2O9CdKl6UGm6qFgXroWesBle5/2WDklVevo70xgOzKFtkVMbsRMb+9e6qZZbyCjDh6
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Ym0H6+2stYUHC4ucrmHw3FbvS4ko9omWMj5xyPDUP2x/Ls2AfJSZR9lqPty8yqDTObHiuEPv8q0e0qw+PJIp4kaY8tAFwc
IXlphANJIeKgAmbfEYyboKzG8Qe+u5gA1gYKFl5zr/WZX0drqM5NG/CZzqfQ=";
System.out.println("Public Key : " + strPublicKey);
System.out.println("Private Key : " + strPrivateKey);
//1.私钥加密加密
byte[] keyPrivateBytes = Base64.decodeBase64(strPrivateKey);
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyPrivateBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("私钥加密、公钥解密——加密 : " + Base64.encodeBase64String(result));
//2.公钥解密
byte[] keyPublicBytes = Base64.decodeBase64(strPublicKey);
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(keyPublicBytes);
keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, publicKey);
result = cipher.doFinal(result);
System.out.println("私钥加密、公钥解密——解密：" + new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}注意:由于密钥长度的原因，明文的长度有一定的限制， 如果明文数据太长的话，会报如下错误
javax.crypto.IllegalBlockSizeException: Data must not be longer than 245 bytes at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:337) at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:382) at javax.crypto.Cipher.doFinal(Cipher.java:2087) at com.wisdomdd.rsa2.RSA2Test.test2(RSA2Test.java:94) at com.wisdomdd.rsa2.RSA2Test.main(RSA2Test.java:118)
报错原因:
不管明文长度是多少，RSA 生成的密文长度总是固定的。
但是明文长度不能超过密钥长度。比如 Java 默认的 RSA 加密实现不允许明文长度超过密钥长度减去 11(单位是字节，也就是 byte)。也就是说，如果我们定义的密钥(我们可以通过 java.security.KeyPairGenerator.initialize(int keysize) 来定义密钥长度)长度为 1024(单位是位，也就是 bit)，生成的密钥长度就是 1024位 / 8位/字节 = 128字节，那么我们需要加密的明文长度不能超过 128字节 -
11 字节 = 117字节。也就是说，我们最大能将 117 字节长度的明文进行加密，否则会出问题(抛诸如 javax.crypto.IllegalBlockSizeException: Data must not be longer than 53 bytes 的异常)
http://wisdomdd.cn/Wisdom/resource/articleDetail.htm?resourceId=322 一文中在加密与解密时使用小技艺对加密与解密的字节进行拆份,解决明文长度太长的问题
函数test2中使用RSA2的公钥对数据进行加密，使用RSA2私钥对数据进行解密
public static void test2(String src){
try {
//1.初始化密钥
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
//String strPublicKey = Base64.encodeBase64String(rsaPublicKey.getEncoded());
//String strPrivateKey = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
String strPublicKey = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAgdQVFyYvJQ38hBAEJ3Zr3BJ
FtpXauN83ghWtgJ1m92XvshGomjEgKpAxyQf9HqqvZB8U0nW+eNIgTAcKZemIQci/6/+oXMhu+WgdIxlJGLzvhZWaz
7UzfKfCFTiUAh6X+hHRlPisekt/y70pbpkxd+GVbmVF5bGxSBnlhdnKa+lAbZd2sO8jv3fzSD0w3dWDmjKg9OjPxXt
1jnwbj0BmwN4TDiMPSmmDBEz7JHadb6A99cswCVXWz3pgioHzq20ipDZDUdAphtgcyT6TO1eZdwHth1tw0UIcPfUmx
5wMGSVBkP/42/AnvG8Y9ROwvg9XpCu2HI+o/n7Ljht5tknDKwIDAQAB";
String strPrivateKey = "MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCB1BUXJi8lDfyEEAQndm
vcEkW2ldq43zeCFa2AnWb3Ze+yEaiaMSAqkDHJB/0eqq9kHxTSdb540iBMBwpl6YhByL/r/6hcyG75aB0jGUkYvO+FlZrP
tTN8p8IVOJQCHpf6EdGU+Kx6S3/LvSlumTF34ZVuZUXlsbFIGeWF2cpr6UBtl3aw7yO/d/NIPTDd1YOaMqD06M/Fe3WOfB
uPQGbA3hMOIw9KaYMETPskdp1voD31yzAJVdbPemCKgfOrbSKkNkNR0CmG2BzJPpM7V5l3Ae2HW3DRQhw99SbHnAwZJUGQ
//jb8Ce8bxj1E7C+D1ekK7Ycj6j+fsuOG3m2ScMrAgMBAAECggEAEnDqkgA1gCDtdmDEBkr25SqfRmEg0VO7kbm8jGFPR+
Lt2jBR75z8wa77s190H9AE28bicUaSSJ0oQ0RYwMMcPKPkRwRoiM1bngeg4+Rqkp37s9DdTZWie5lkoxkHRQnNcpLnXy63
aSOiQnFbGj+eXDXpwOWXuRm1YdVz2cBm1U71Fy4pKNKU8B/Z/gLucnxotXWVQjhguKIrY0BEdH/0TJlPzlAQQYYuCItA7g
JUNivCv0ecDswG0AchkdAIwbjRFS9Jpc4sWkvlgdYaP33uNjzXQrG7QZxSaCADorB8vFM/c7MxJZuS5hOvIZN5FYTZJ7NW
6ujepHaZKaPfexjYCQKBgQD6CIVP0I6jsqhLsqXr89x2hNqnvxhynfot3bGJzeGhuGYnAnfI/YzhekZ25mqdY5yYkTY2gW
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FORZLH7o+VPS9ADC9BfhGvm+7d0eczKG6YP79Icqz/E7N6PzOzB2E2HjuYlqJRxkGeUSXcvr7Rvljampd1WY3qo8koDj8w
lkOGzjOwMRL3kpikhZw285jZ9czu5ExW8wQYr0gERPpqLBcEnaCmwvYokATBkCgYEA1lPCbn8um4e7faqDVYm0H6+2stYU
HC4ucrmHw3FbvS4ko9omWMj5xyPDUP2x/Ls2AfJSZR9lqPty8yqDTObHiuEPv8q0e0qw+PJIp4kaY8tAFwcIXlphANJIeK
gAmbfEYyboKzG8Qe+u5gA1gYKFl5zr/WZX0drqM5NG/CZzqfQ=";
System.out.println("Public Key : " + strPublicKey);
System.out.println("Private Key : " + strPrivateKey);
System.out.println("加密前数据:" + src);
//1.公钥加密
byte[] keyPublicBytes = Base64.decodeBase64(strPublicKey);
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(keyPublicBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] result = cipher.doFinal(src.getBytes());
System.out.println("公钥加密、私钥解密——加密 : " + Base64.encodeBase64String(result));
//2.私钥解密
byte[] keyPrivateBytes = Base64.decodeBase64(strPrivateKey);
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyPrivateBytes);
keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
result = cipher.doFinal(result);
System.out.println("公钥加密、私钥解密——解密：" + new String(result));
} catch (Exception e) {
e.printStackTrace();
}
}公钥，私钥生成工具, 本文代码适用于 1024, 2048两种规则生成的密钥
实例代码中提供了 公钥私钥生成工具
