java rsa 解密 報:javax.crypto.IllegalBlockSizeException: Data must not be longer than 117 bytes

java教程 · 發表 2018-10-08

    at com.asymmetric.rsa.TestRSA.main(TestRSA.java:33)

異常解釋

加密塊大小錯誤,rsa 加密 塊大小為117 ,解密塊大小為128 ,和公鑰加密或者私鑰加密無關,

測試程式碼如下:

package com.asymmetric.rsa;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

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



public class TestRSA {
    
    public static String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDQgEoj3z9JrdPNI23DbMQkl3gkGuDke7iBr5yrYyqolkTyxuBLWFwHNuGv4VKOj9fXg61QxpaJ/fxDBvMvmkBSRowHBloGFceVTx8wV/8u0DcjvTCu0IZ1zp6wjG6xBn5j66Sg/q+9hvaY2p7fkKmsvcW6VoNPgQHU1Cf01DLZmQIDAQAB+oXcINOiE3AsuZ4VJmwNZg9Y/7fY+OFRS2JAh5YMsrv2qyoGP+Z9ksre26NYR+Lt91B2lhdwJHLpQpziaANZm/ONb31fj/lwIDAQAB";
    public static String privateKey = "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";
    
    private static String algorithm = "RSA"; //$NON-NLS-1$
    
    private static String data = "這是一個test"; //$NON-NLS-1$
    
    public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException {
        byte[] test = testEncrypt(privateKey,data);
        String testDecrypt = testDecrypt(publicKey, test);
        System.out.println(testDecrypt);
    }
    

    /**
     * 加密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeySpecException
     * @throws NoSuchPaddingException
     * @throws IllegalBlockSizeException
     * @throws BadPaddingException
     * @throws InvalidKeyException
     */
    public static byte[] testEncrypt(String key,String data) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException{
        byte[] decode = Base64.getDecoder().decode(key);
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PrivateKey generatePrivate = kf.generatePrivate(pkcs8EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(1, generatePrivate);
        byte[] doFinal = ci.doFinal(data.getBytes());
//        return Base64.getEncoder().encodeToString(doFinal);
        return doFinal;
    }

    
    /**
     * 解密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException 
     * @throws NoSuchPaddingException 
     * @throws InvalidKeySpecException 
     * @throws BadPaddingException 
     * @throws IllegalBlockSizeException 
     */
    public static String testDecrypt(String key,byte[] data) throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException, InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException{
        byte[] decode = Base64.getDecoder().decode(key);
//        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode); //java底層 RSA公鑰只支援X509EncodedKeySpec這種格式
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PublicKey generatePublic = kf.generatePublic(x509EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(1,generatePublic);
//        byte[] doFinal = ci.doFinal(Base64.getDecoder().decode(data));
        byte[] doFinal = ci.doFinal(Base64.getDecoder().decode(data));
        return Base64.getEncoder().encodeToString(doFinal);
    }
    
}

問題點:

後來發現是解密的時候.cipher.init(1,generatePublic)  cipher 模式填錯了,1就代表是加密模式,2是解密模式

將解密方法裡的cipher初始化改為 cipher.init(2,generatePublic) 即可

後來看到這個異常用大量資料去測試,也報這個異常,說明rsa加密必須對加密資料進行分組加密

查api指出:IllegalBlockSizeException - 如果此 Cipher 為 Cipher 塊,未請求任何填充(只針對加密模式),並且由此 Cipher 處理的資料總輸入長度不是塊大小的倍數;如果此加密演算法無法處理所提供的輸入資料。

修正後的程式碼:

package com.asymmetric.rsa;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

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



public class TestRSA {
    
    public static String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDQgEoj3z9JrdPNI23DbMQkl3gkGuDke7iBr5yrYyqolkTyxuBLWFwHNuGv4VKOj9fXg61QxpaJ/fxDBvMvmkBSRowHBloGFceVTx8wV/8u0DcjvTCu0IZ1zp6wjG6xBn5j66Sg/q+9hvaY2p7fkKmsvcW6VoNPgQHU1Cf01DLZmQIDAQAB+oXcINOiE3AsuZ4VJmwNZg9Y/7fY+OFRS2JAh5YMsrv2qyoGP+Z9ksre26NYR+Lt91B2lhdwJHLpQpziaANZm/ONb31fj/lwIDAQAB";
    public static String privateKey = "MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBANCASiPfP0mt080jbcNsxCSXeCQa4OR7uIGvnKtjKqiWRPLG4EtYXAc24a/hUo6P19eDrVDGlon9/EMG8y+aQFJGjAcGWgYVx5VPHzBX/y7QNyO9MK7QhnXOnrCMbrEGfmPrpKD+r72G9pjant+Qqay9xbpWg0+BAdTUJ/TUMtmZAgMBAAECgYBSozY/Z4FW+31h5fPgK+DFu/8TGFAgXuTvCaJnz2Md9IkZTDejxT6cYWUr53toI5zhvz/XLw6FXNQ54KxMJq/s9PiZYUgq/PMrnyU4gBSTm5BmiWjdaGicVEZ1lofHjpkAchPNW/CzwxD8AeKI7QaObE+EkWbLAi6sa+nRdHKgrQJBAOwYLD2DncU15XCKS0RNzTrNohdBQcisOPHdtQO0CGZlxx3xjuU4WL6/EpdmbjTeYbOSDKCmY5vyVbYZdOWfEs8CQQDiFIwWpvW2WLxLVw3i2P55WmMMXuecwEzg++ae3Ht7nW0zNcWSsyvHh40sM8XqEzmWOzMY6JOePbkuVfWTc4cXAkBRzf5mQhiEoKwjVofF3v9hhKbJT/8vPR1uENgLtHHEqTdZFL3ihqeZUDNs6jz9bKCFy/E8KOsSueEg+6kZdwjZAkEAj2RW4fstd2VasDJb5ViaNqAEmJENOBej60L6KCJR07qqy0M8t+oaR2iLOtDvo6Jj8QxFQXQqRMCDVodAxjANKwJAL3KuaqA6kdy9RxdV3uP8nRXLY7C/1ZIK6U0pyZqKXEwpD+7Ar3hwwhPz9TeuoqjB/cCknZjw70BQFQ0/VUHW2g==";
    
    private static String algorithm = "RSA"; //$NON-NLS-1$
    private static final int MAX_ENCRYPT_BLOCK = 117;
    private static final int MAX_DECRYPT_BLOCK = 128;
    private static String data = "test jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihgtest jiojiogeiojigouihg"; //$NON-NLS-1$
    
    public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException, IOException {
        String test = testEncrypt(privateKey,data);
        String testDecrypt = testDecrypt(publicKey, test);
        System.out.println(testDecrypt);
        
    }
    

    /**
     * 加密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeySpecException
     * @throws NoSuchPaddingException
     * @throws IllegalBlockSizeException
     * @throws BadPaddingException
     * @throws InvalidKeyException
     * @throws IOException 
     */
    public static String testEncrypt(String key,String data) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException, IOException{
        byte[] decode = Base64.getDecoder().decode(key);
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PrivateKey generatePrivate = kf.generatePrivate(pkcs8EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(Cipher.ENCRYPT_MODE, generatePrivate);
        
        byte[] bytes = data.getBytes();
        int inputLen = bytes.length;
        int offLen = 0;//偏移量
        int i = 0;
        ByteArrayOutputStream bops = new ByteArrayOutputStream();
        while(inputLen - offLen > 0){
            byte [] cache;
            if(inputLen - offLen > 117){
                cache = ci.doFinal(bytes, offLen,117);
            }else{
                cache = ci.doFinal(bytes, offLen,inputLen - offLen);
            }
            bops.write(cache);
            i++;
            offLen = 117 * i;
        }
        bops.close();
        byte[] encryptedData = bops.toByteArray();
        String encodeToString = Base64.getEncoder().encodeToString(encryptedData);
        return encodeToString;
    }
    


    
    /**
     * 解密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException 
     * @throws NoSuchPaddingException 
     * @throws InvalidKeySpecException 
     * @throws BadPaddingException 
     * @throws IllegalBlockSizeException 
     * @throws IOException 
     */
    public static String testDecrypt(String key,String data) throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException, InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException, IOException{
        byte[] decode = Base64.getDecoder().decode(key);
//      PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode); //java底層 RSA公鑰只支援X509EncodedKeySpec這種格式
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PublicKey generatePublic = kf.generatePublic(x509EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(Cipher.DECRYPT_MODE,generatePublic);
        
        byte[] bytes = Base64.getDecoder().decode(data);
        int inputLen = bytes.length;
        int offLen = 0;
        int i = 0;
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        while(inputLen - offLen > 0){
            byte[] cache;
            if(inputLen - offLen > 128){
                cache = ci.doFinal(bytes,offLen,128); 
            }else{
                cache = ci.doFinal(bytes,offLen,inputLen - offLen);
            }
            byteArrayOutputStream.write(cache);
            i++;
            offLen = 128 * i;
            
        }
        byteArrayOutputStream.close();
        byte[] byteArray = byteArrayOutputStream.toByteArray();
        return new String(byteArray);
    }
    
    
    
}