IOS & JAVA RSA Encryption & Decryption

 

　　在網上找了許多篇關於RSA加密解密的文章與博客，是很有幫助，但比較零散與不簡潔。

　　(至於RSA的基本原理，大家可以看 阮一峰的網絡日志 的 RSA算法原理（一） 和 RSA算法原理（二） )

　　這篇文章只是做一個整理，幫大家理清一下步驟的而已（ 英文版本請看 RSA Encrypt and Decrypt in IOS and JAVA ）。

 

　　一、首先，打開Terminal， 生成必要的公鑰、私鑰、證書:

　　

openssl genrsa -out private_key.pem 1024

openssl req -new -key private_key.pem -out rsaCertReq.csr

openssl x509 -req -days 3650 -in rsaCertReq.csr -signkey private_key.pem -out rsaCert.crt

openssl x509 -outform der -in rsaCert.crt -out public_key.der　　　　　　　　　　　　　　　// Create public_key.der For IOS
 
openssl pkcs12 -export -out private_key.p12 -inkey private_key.pem -in rsaCert.crt　　// Create private_key.p12 For IOS. 這一步，請記住你輸入的密碼，IOS代碼里會用到

openssl rsa -in private_key.pem -out rsa_public_key.pem -pubout　　　　　　　　　　　　　// Create rsa_public_key.pem For Java
　
openssl pkcs8 -topk8 -in private_key.pem -out pkcs8_private_key.pem -nocrypt　　　　　// Create pkcs8_private_key.pem For Java

 

　　上面七個步驟，總共生成7個文件。其中　public_key.der 和 private_key.p12 這對公鑰私鑰是給IOS用的， rsa_public_key.pem 和 pkcs8_private_key.pem　是給JAVA用的。

　　它們的源都來自一個私鑰：private_key.pem ， 所以IOS端加密的數據，是可以被JAVA端解密的，反過來也一樣。

 

　　二、IOS 端:

　　2017.0306更新，文章過時了啦，大家請參考一個大神的Github: Objective-C-RSA 

 

　　三、 JAVA 端：

　　RSAEncryptor.java：

package com.modules.Encryptor;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
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;
import java.util.ArrayList;
import java.util.List;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class RSAEncryptor {

    
    public static void main(String[] args){  
        
        String privateKeyPath = "/Users/Love/Desktop/RSA_KEYS/rsa_public_key.pem";        // replace your public key path here
        String publicKeyPath =  "/Users/Love/Desktop/RSA_KEYS/pkcs8_private_key.pem";     // replace your private path here
        RSAEncryptor rsaEncryptor = new RSAEncryptor(privateKeyPath, publicKeyPath);

        try {
            
            String test = "JAVA";
            String testRSAEnWith64 = rsaEncryptor.encryptWithBase64(test);
            String testRSADeWith64 = rsaEncryptor.decryptWithBase64(testRSAEnWith64);
            System.out.println("\nEncrypt: \n" + testRSAEnWith64);
            System.out.println("\nDecrypt: \n" + testRSADeWith64);
            
            // NSLog the encrypt string from Xcode , and paste it here.
            // 請粘貼來自IOS端加密后的字符串
//            String rsaBase46StringFromIOS =
//                    "nIIV7fVsHe8QquUbciMYbbumoMtbBuLsCr2yMB/WAhm+S/kGRPlf+k2GH8imZIYQ" + "\r" +
//                    "QBDssVLQmS392QlxS87hnwMRJIzWw6vdRv/k79TgTfu6tI/9QTqIOvNlQIqtIcVm" + "\r" +
//                    "R/suvydoymKgdlB+ce5/tHSxfqEOLLrL1Zl2PqJSP4A=";
//            
//            String decryptStringFromIOS = rsaEncryptor.decryptWithBase64(rsaBase46StringFromIOS);
//            System.out.println("Decrypt result from ios client: \n" + decryptStringFromIOS);
            
        } catch (Exception e) {
            e.printStackTrace();
        }

    }





    /**
     * @param publicKeyFilePath     
     * @param privateKeyFilePath    
     */
    public RSAEncryptor(String publicKeyFilePath, String privateKeyFilePath) throws Exception {
        String public_key = getKeyFromFile(publicKeyFilePath);
        String private_key = getKeyFromFile(privateKeyFilePath);
        loadPublicKey(public_key);  
        loadPrivateKey(private_key);  
    }
    public RSAEncryptor() {
        // load the PublicKey and PrivateKey manually
    }
    
    
    public String getKeyFromFile(String filePath) throws Exception {
        BufferedReader bufferedReader = new BufferedReader(new FileReader(filePath));
        
        String line = null;
        List<String> list = new ArrayList<String>();
        while ((line = bufferedReader.readLine()) != null){
            list.add(line);
        }
        
        // remove the firt line and last line
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 1; i < list.size() - 1; i++) {
            stringBuilder.append(list.get(i)).append("\r");
        }
        
        String key = stringBuilder.toString();
        return key;
    }
    
    public String decryptWithBase64(String base64String) throws Exception {
        //  http://commons.apache.org/proper/commons-codec/ : org.apache.commons.codec.binary.Base64
        // sun.misc.BASE64Decoder
        byte[] binaryData = decrypt(getPrivateKey(), new BASE64Decoder().decodeBuffer(base64String) /*org.apache.commons.codec.binary.Base64.decodeBase64(base46String.getBytes())*/);
        String string = new String(binaryData);
        return string;
    }
    
    public String encryptWithBase64(String string) throws Exception {
        //  http://commons.apache.org/proper/commons-codec/ : org.apache.commons.codec.binary.Base64
        // sun.misc.BASE64Encoder
        byte[] binaryData = encrypt(getPublicKey(), string.getBytes());
        String base64String = new BASE64Encoder().encodeBuffer(binaryData) /* org.apache.commons.codec.binary.Base64.encodeBase64(binaryData) */;
        return base64String;
    }
  
    
    
    // convenient properties
    public static RSAEncryptor sharedInstance = null;
    public static void setSharedInstance (RSAEncryptor rsaEncryptor) {
        sharedInstance = rsaEncryptor;
    }
    
    
    
    
    // From: http://blog.csdn.net/chaijunkun/article/details/7275632

    /** 
     * 私鑰 
     */  
    private RSAPrivateKey privateKey;  
  
    /** 
     * 公鑰 
     */  
    private RSAPublicKey publicKey;  
      
    /** 
     * 獲取私鑰 
     * @return 當前的私鑰對象 
     */  
    public RSAPrivateKey getPrivateKey() {  
        return privateKey;  
    }  
  
    /** 
     * 獲取公鑰 
     * @return 當前的公鑰對象 
     */  
    public RSAPublicKey getPublicKey() {  
        return publicKey;  
    }  
  
    /** 
     * 隨機生成密鑰對 
     */  
    public void genKeyPair(){  
        KeyPairGenerator keyPairGen= null;  
        try {  
            keyPairGen= KeyPairGenerator.getInstance("RSA");  
        } catch (NoSuchAlgorithmException e) {  
            e.printStackTrace();  
        }  
        keyPairGen.initialize(1024, new SecureRandom());  
        KeyPair keyPair= keyPairGen.generateKeyPair();  
        this.privateKey= (RSAPrivateKey) keyPair.getPrivate();  
        this.publicKey= (RSAPublicKey) keyPair.getPublic();  
    }  
  
    /** 
     * 從文件中輸入流中加載公鑰 
     * @param in 公鑰輸入流 
     * @throws Exception 加載公鑰時產生的異常 
     */  
    public void loadPublicKey(InputStream in) throws Exception{  
        try {  
            BufferedReader br= new BufferedReader(new InputStreamReader(in));  
            String readLine= null;  
            StringBuilder sb= new StringBuilder();  
            while((readLine= br.readLine())!=null){  
                if(readLine.charAt(0)=='-'){  
                    continue;  
                }else{  
                    sb.append(readLine);  
                    sb.append('\r');  
                }  
            }  
            loadPublicKey(sb.toString());  
        } catch (IOException e) {  
            throw new Exception("公鑰數據流讀取錯誤");  
        } catch (NullPointerException e) {  
            throw new Exception("公鑰輸入流為空");  
        }  
    }  
  
    /** 
     * 從字符串中加載公鑰 
     * @param publicKeyStr 公鑰數據字符串 
     * @throws Exception 加載公鑰時產生的異常 
     */  
    public void loadPublicKey(String publicKeyStr) throws Exception{  
        try {  
            BASE64Decoder base64Decoder= new BASE64Decoder();  
            byte[] buffer= base64Decoder.decodeBuffer(publicKeyStr);
            KeyFactory keyFactory= KeyFactory.getInstance("RSA");  
            X509EncodedKeySpec keySpec= new X509EncodedKeySpec(buffer);  
            this.publicKey= (RSAPublicKey) keyFactory.generatePublic(keySpec);  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("無此算法");  
        } catch (InvalidKeySpecException e) {  
            throw new Exception("公鑰非法");  
        } catch (IOException e) {  
            throw new Exception("公鑰數據內容讀取錯誤");  
        } catch (NullPointerException e) {  
            throw new Exception("公鑰數據為空");  
        }  
    }  
  
    /** 
     * 從文件中加載私鑰 
     * @param keyFileName 私鑰文件名 
     * @return 是否成功 
     * @throws Exception  
     */  
    public void loadPrivateKey(InputStream in) throws Exception{  
        try {  
            BufferedReader br= new BufferedReader(new InputStreamReader(in));  
            String readLine= null;  
            StringBuilder sb= new StringBuilder();  
            while((readLine= br.readLine())!=null){  
                if(readLine.charAt(0)=='-'){  
                    continue;  
                }else{  
                    sb.append(readLine);  
                    sb.append('\r');  
                }  
            }  
            loadPrivateKey(sb.toString());  
        } catch (IOException e) {  
            throw new Exception("私鑰數據讀取錯誤");  
        } catch (NullPointerException e) {  
            throw new Exception("私鑰輸入流為空");  
        }  
    }  
  
    public void loadPrivateKey(String privateKeyStr) throws Exception{  
        try {  
            BASE64Decoder base64Decoder= new BASE64Decoder();  
            byte[] buffer= base64Decoder.decodeBuffer(privateKeyStr);  
            PKCS8EncodedKeySpec keySpec= new PKCS8EncodedKeySpec(buffer);  
            KeyFactory keyFactory= KeyFactory.getInstance("RSA");  
            this.privateKey= (RSAPrivateKey) keyFactory.generatePrivate(keySpec);  
        } catch (NoSuchAlgorithmException e) {  
            throw new Exception("無此算法");  
        } catch (InvalidKeySpecException e) {  
            e.printStackTrace();
            throw new Exception("私鑰非法");  
        } catch (IOException e) {  
            throw new Exception("私鑰數據內容讀取錯誤");  
        } catch (NullPointerException e) {  
            throw new Exception("私鑰數據為空");  
        }  
    }  
  
    /** 
     * 加密過程 
     * @param publicKey 公鑰 
     * @param plainTextData 明文數據 
     * @return 
     * @throws Exception 加密過程中的異常信息 
     */  
    public byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception{  
        if(publicKey== null){  
            throw new Exception("加密公鑰為空, 請設置");  
        }  
        Cipher cipher= null;  
        try {  
            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("無此加密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        }catch (InvalidKeyException e) {  
            throw new Exception("加密公鑰非法,請檢查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("明文長度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("明文數據已損壞");  
        }  
    }  
  
    /** 
     * 解密過程 
     * @param privateKey 私鑰 
     * @param cipherData 密文數據 
     * @return 明文 
     * @throws Exception 解密過程中的異常信息 
     */  
    public byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception{  
        if (privateKey== null){  
            throw new Exception("解密私鑰為空, 請設置");  
        }  
        Cipher cipher= null;  
        try {  
            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("無此解密算法");  
        } catch (NoSuchPaddingException e) {  
            e.printStackTrace();  
            return null;  
        }catch (InvalidKeyException e) {  
            throw new Exception("解密私鑰非法,請檢查");  
        } catch (IllegalBlockSizeException e) {  
            throw new Exception("密文長度非法");  
        } catch (BadPaddingException e) {  
            throw new Exception("密文數據已損壞");  
        }         
    }  
  
    
    
    /** 
     * 字節數據轉字符串專用集合 
     */  
    private static final char[] HEX_CHAR= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; 
    
    /** 
     * 字節數據轉十六進制字符串 
     * @param data 輸入數據 
     * @return 十六進制內容 
     */  
    public static String byteArrayToString(byte[] data){  
        StringBuilder stringBuilder= new StringBuilder();  
        for (int i=0; i<data.length; i++){  
            //取出字節的高四位 作為索引得到相應的十六進制標識符 注意無符號右移  
            stringBuilder.append(HEX_CHAR[(data[i] & 0xf0)>>> 4]);  
            //取出字節的低四位 作為索引得到相應的十六進制標識符  
            stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);  
            if (i<data.length-1){  
                stringBuilder.append(' ');  
            }  
        }  
        return stringBuilder.toString();  
    }  


｝