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我正在开发一个现有的应用程序，但尚未编写它。

在此方法中解密用户名和密码期间，我得到了这个异常（javax.crypto.BadPaddingException：pad block损坏）：

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    byte[] decrypted = cipher.doFinal(encrypted);//ERROR HERE////////////////////////////////////////////////////////////////////////////
    return decrypted;
}

encrypted 的值是一个字节数组，其中包含 -89 到 126 之间的 16 个数值。任何人都可以看到这段代码的问题吗？这是所有重要的代码：

在 Settings 类（Encryptor 类的客户端）内部：

private final String ENCRYPTION_SEED = "MH8734()9Akg&*3d";

    public void loadAuthorization() {
                try {
                    username = getStringEncrypted(sharedPreferences, KEY_USERNAME);
                    password = getStringEncrypted(sharedPreferences, KEY_PASSWORD);
                    isAuthorized = sharedPreferences.getBoolean(KEY_IS_AUTHORIZED,
                            false);
                } catch (Exception e) {
                    Log.e("LOAD ERROR", "Exception during loading authorization");
                }
            }

    public String getStringEncrypted(SharedPreferences sharedPreferences,
            String key) {
        try {
            String valueEncrypted = sharedPreferences.getString(key, "NULL");
            String valueDecrypted = Encryptor.decrypt(ENCRYPTION_SEED + key,
                    valueEncrypted);
            return valueDecrypted;
        } catch (Exception e) {
            return "NULL";
        }
    }

public void saveAuthorization() {
    SharedPreferences.Editor ed = sharedPreferences.edit();
    try {
        setStringEncrypted(ed, KEY_USERNAME, username);
        setStringEncrypted(ed, KEY_PASSWORD, password);
        ed.putBoolean(KEY_IS_AUTHORIZED, isAuthorized);
    } catch (Exception e) {
            Log.e("SAVE ERROR", "Exception during saving authorization");
        }
        ed.commit();
    }

public void setStringEncrypted(SharedPreferences.Editor ed, String key,
            String value) {
        try {
            String valueEncrypted = Encryptor.encrypt(ENCRYPTION_SEED + key,
                    value);
            ed.putString(key, valueEncrypted);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

完整的加密器类：

package com.boolbalabs.petlinx.settings;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class Encryptor {

    private final static String HEX = "0123456789ABCDEF";

    private static void appendHex(StringBuffer sb, byte b) {
        sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
    }

    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decrypted = cipher.doFinal(encrypted);//ERROR HERE////////////////////////////////////////////////////////////////////////////
        return decrypted;
    }


    public static String decrypt(String seed, String encrypted) throws Exception {
        byte[] rawKey = getRawKey(seed.getBytes());
        byte[] enc = toByte(encrypted);
        byte[] result = decrypt(rawKey, enc);
        return new String(result);
    }

    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(clear);
        return encrypted;
    }

    public static String encrypt(String seed, String cleartext) throws Exception {
        byte[] rawKey = getRawKey(seed.getBytes());
        byte[] result = encrypt(rawKey, cleartext.getBytes());
        return toHex(result);
    }
    public static String fromHex(String hex) {
        return new String(toByte(hex));
    }

    private static byte[] getRawKey(byte[] seed) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
        sr.setSeed(seed);
        kgen.init(128, sr); // 192 and 256 bits may not be available
        SecretKey skey = kgen.generateKey();
        byte[] raw = skey.getEncoded();
        return raw;
    }

    public static byte[] toByte(String hexString) {
        int len = hexString.length()/2;
        byte[] result = new byte[len];
        for (int i = 0; i < len; i++)
            result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
        return result;
    }
    public static String toHex(byte[] buf) {
        if (buf == null)
            return "";
        StringBuffer result = new StringBuffer(2*buf.length);
        for (int i = 0; i < buf.length; i++) {
            appendHex(result, buf[i]);
        }
        return result.toString();
    }
    public static String toHex(String txt) {
        return toHex(txt.getBytes());
    }
}

这个答案建议不要使用 SecureRandom 来生成密钥。我正在处理的应用程序中的代码确实为此使用了 SecureRandom。我该如何解决？

这是使用 SecureRandom 的代码。

private static byte[] getRawKey(byte[] seed) throws Exception {
    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
    sr.setSeed(seed);
    kgen.init(128, sr); // 192 and 256 bits may not be available
    SecretKey skey = kgen.generateKey();
    byte[] raw = skey.getEncoded();
    return raw;
}
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