RSA加密解密演算法工具類
阿新 • • 發佈:2019-02-09
1.RSA介紹
2.RSA加密解密工具類實現
import javax.crypto.Cipher;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
/**
* author:houkai
* Date: 2017/11/6
* describe: 非對稱加密。私鑰加密 & 私鑰解密 & 私鑰簽名
*/
public class RSAUtil {
public static void main(String ...args){ RSAUtil rsa = RSAUtil.create(); String pubKey = rsa.getPublicKey(); String priKey = rsa.getPrivateKey(); System.out.println("公鑰:"+ pubKey); System.out.println("私鑰:"+ priKey); //原文 StringBuffer res = new StringBuffer(); res.append("123456"); System.out.println("原文對比:"+res.toString()); System.out.println("-----------------------"); String enStr = rsa.encodeByPublicKey(res.toString(), pubKey); String deStr = rsa.decodeByPrivateKey(enStr, priKey); System.out.println("公鑰加密:"+enStr); System.out.println("私鑰解密:"+deStr); System.out.println("------------------------"); enStr = rsa.encodeByPrivateKey(res.toString(), priKey); deStr = rsa.decodeByPublicKey(enStr, pubKey); System.out.println("私鑰加密:"+enStr); System.out.println("公鑰解密:"+deStr); } public static final String KEY_ALGORITHM = "RSA"; public static final String split = " ";//分隔符 public static final int max = 117; //加密分段長度//不可超過117 private static RSAUtil me; private RSAUtil(){}//單例 /** * RSA 公鑰 私鑰對 * @return */ public static RSAUtil create(){ if (me==null) { me = new RSAUtil(); } //生成公鑰、私鑰 try { KeyPairGenerator kpg = KeyPairGenerator.getInstance(KEY_ALGORITHM); kpg.initialize(512); KeyPair kp = kpg.generateKeyPair(); me.publicKey = (RSAPublicKey) kp.getPublic(); me.privateKey = (RSAPrivateCrtKey) kp.getPrivate(); } catch (Exception e) { e.printStackTrace(); } return me; } private RSAPublicKey publicKey; private RSAPrivateCrtKey privateKey; /**獲取公鑰*/ public String getPublicKey(){ return parseByte2HexStr(publicKey.getEncoded()); } /**獲取私鑰*/ public String getPrivateKey(){ return parseByte2HexStr(privateKey.getEncoded()); } /** * 加密-公鑰 * */ public String encodeByPublicKey(String res,String key){ byte[] resBytes = res.getBytes(); byte[] keyBytes = parseHexStr2Byte(key);//先把公鑰轉為2進位制 StringBuffer result = new StringBuffer();//結果 //如果超過了100個位元組就分段 if (keyBytes.length<=max) {//不超過直接返回即可 return encodePub(resBytes, keyBytes); }else { int size = resBytes.length/max + (resBytes.length%max>0?1:0); for (int i = 0; i < size; i++) { int len = i==size-1?resBytes.length%max:max; byte[] bs = new byte[len];//臨時陣列 System.arraycopy(resBytes, i*max, bs, 0, len); result.append(encodePub(bs, keyBytes)); if(i!=size-1)result.append(split); } return result.toString(); } } /** * 加密-私鑰 * */ public String encodeByPrivateKey(String res,String key){ byte[] resBytes = res.getBytes(); byte[] keyBytes = parseHexStr2Byte(key); StringBuffer result = new StringBuffer(); //如果超過了100個位元組就分段 if (keyBytes.length<=max) {//不超過直接返回即可 return encodePri(resBytes, keyBytes); }else { int size = resBytes.length/max + (resBytes.length%max>0?1:0); for (int i = 0; i < size; i++) { int len = i==size-1?resBytes.length%max:max; byte[] bs = new byte[len];//臨時陣列 System.arraycopy(resBytes, i*max, bs, 0, len); result.append(encodePri(bs, keyBytes)); if(i!=size-1)result.append(split); } return result.toString(); } } /** * 解密-公鑰 * */ public String decodeByPublicKey(String res,String key){ byte[] keyBytes = parseHexStr2Byte(key); //先分段 String[] rs = res.split("\\"+split); //分段解密 if(rs!=null){ int len = 0; //組合byte[] byte[] result = new byte[rs.length*max]; for (int i = 0; i < rs.length; i++) { byte[] bs = decodePub(parseHexStr2Byte(rs[i]), keyBytes); System.arraycopy(bs, 0, result, i*max, bs.length); len+=bs.length; } byte[] newResult = new byte[len]; System.arraycopy(result, 0, newResult, 0, len); //還原字串 return new String(newResult); } return null; } /**解密-私鑰*/ public String decodeByPrivateKey(String res,String key){ byte[] keyBytes = parseHexStr2Byte(key); //先分段 String[] rs = res.split("\\"+split); //分段解密 if(rs!=null){ int len = 0; //組合byte[] byte[] result = new byte[rs.length*max]; for (int i = 0; i < rs.length; i++) { byte[] bs = decodePri(parseHexStr2Byte(rs[i]), keyBytes); System.arraycopy(bs, 0, result, i*max, bs.length); len+=bs.length; } byte[] newResult = new byte[len]; System.arraycopy(result, 0, newResult, 0, len); //還原字串 return new String(newResult); } return null; } /**將二進位制轉換成16進位制 */ private static String parseByte2HexStr(byte buf[]) { 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()); } return sb.toString(); } /** * 將16進位制轉換為二進位制 * */ private static byte[] parseHexStr2Byte(String hexStr) { if (hexStr.length() < 1) return null; byte[] result = new byte[hexStr.length()/2]; for (int i = 0;i< hexStr.length()/2; i++) { int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16); int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16); result[i] = (byte) (high * 16 + low); } return result; } /**加密-公鑰-無分段*/ private String encodePub(byte[] res,byte[] keyBytes){ X509EncodedKeySpec x5 = new X509EncodedKeySpec(keyBytes);//用2進位制的公鑰生成x509 try { KeyFactory kf = KeyFactory.getInstance(KEY_ALGORITHM); Key pubKey = kf.generatePublic(x5);//用KeyFactory把x509生成公鑰pubKey Cipher cp = Cipher.getInstance(kf.getAlgorithm());//生成相應的Cipher cp.init(Cipher.ENCRYPT_MODE, pubKey);//給cipher初始化為加密模式,以及傳入公鑰pubKey return parseByte2HexStr(cp.doFinal(res));//以16進位制的字串返回 } catch (Exception e) { System.out.println("公鑰加密失敗"); e.printStackTrace(); } return null; } /**加密-私鑰-無分段*/ private String encodePri(byte[] res,byte[] keyBytes){ PKCS8EncodedKeySpec pk8 = new PKCS8EncodedKeySpec(keyBytes); try { KeyFactory kf = KeyFactory.getInstance(KEY_ALGORITHM); Key priKey = kf.generatePrivate(pk8); Cipher cp = Cipher.getInstance(kf.getAlgorithm()); cp.init(Cipher.ENCRYPT_MODE, priKey); return parseByte2HexStr(cp.doFinal(res)); } catch (Exception e) { System.out.println("私鑰加密失敗"); e.printStackTrace(); } return null; } /**解密-公鑰-無分段*/ private byte[] decodePub(byte[] res,byte[] keyBytes){ X509EncodedKeySpec x5 = new X509EncodedKeySpec(keyBytes); try { KeyFactory kf = KeyFactory.getInstance(KEY_ALGORITHM); Key pubKey = kf.generatePublic(x5); Cipher cp = Cipher.getInstance(kf.getAlgorithm()); cp.init(Cipher.DECRYPT_MODE, pubKey); return cp.doFinal(res); } catch (Exception e) { System.out.println("公鑰解密失敗"); e.printStackTrace(); } return null; } /**解密-私鑰-無分段*/ private byte[] decodePri(byte[] res,byte[] keyBytes){ PKCS8EncodedKeySpec pk8 = new PKCS8EncodedKeySpec(keyBytes); try { KeyFactory kf = KeyFactory.getInstance(KEY_ALGORITHM); Key priKey = kf.generatePrivate(pk8); Cipher cp = Cipher.getInstance(kf.getAlgorithm()); cp.init(Cipher.DECRYPT_MODE, priKey); return cp.doFinal(res); } catch (Exception e) { System.out.println("私鑰解密失敗"); e.printStackTrace(); } return null; }
}