BadPaddingException 在 Android 中解密加密数据

2022-01-10 00:00:00 encryption cryptography android java

我是 Android 安全概念的新手.

I'm new to Android security concepts.

我一直在阅读一些博客以了解我们可以使用公钥加密数据并使用相应的私钥对其进行解密.加密似乎没有任何问题，但是当我尝试解密它时，它会抛出:

I have been reading some blogs to get to know about we can encrypt data using Public key and can decrypt it using respective Private key. Encryption seems to be doesn't have any problem, but when I try to decrypt it, it throws:

javax.crypto.BadPaddingException: error:0407106B:rsa routines:RSA_padding_check_PKCS1_type_2:block type is not 02.

javax.crypto.BadPaddingException: error:0407106B:rsa routines:RSA_padding_check_PKCS1_type_2:block type is not 02.

我的代码如下:

public String RSAEncrypt(final String plain, PublicKey publicKey ) throws NoSuchAlgorithmException, NoSuchPaddingException,
    InvalidKeyException, IllegalBlockSizeException, BadPaddingException {

    Cipher cipher = Cipher.getInstance("RSA");
    cipher.init(Cipher.ENCRYPT_MODE, publicKey);
    byte [] encryptedBytes = cipher.doFinal(plain.getBytes());
    String encrypted = bytesToString(encryptedBytes);
    System.out.println("EEncrypted?????" + encrypted );
    return encrypted;
}

public String RSADecrypt(String encryptedBytes,PrivateKey privateKey ) throws NoSuchAlgorithmException, NoSuchPaddingException,
    InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchProviderException {
    Cipher cipher1 = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    cipher1.init(Cipher.DECRYPT_MODE, privateKey);
    byte [] decryptedBytes = cipher1.doFinal(stringToBytes(encryptedBytes));

    String decrypted = new String(decryptedBytes);
    System.out.println("DDecrypted?????" + decrypted);
    return decrypted;
    }

public  String bytesToString(byte[] b) {
    byte[] b2 = new byte[b.length + 1];
    b2[0] = 1;
    System.arraycopy(b, 0, b2, 1, b.length);
    return new BigInteger(b2).toString(36);
}

public  byte[] stringToBytes(String s) {
    byte[] b2 = new BigInteger(s, 36).toByteArray();
    return Arrays.copyOfRange(b2, 1, b2.length);
}

堆栈跟踪如下:

07-28 11:27:35.119: I/System.out(22933): KEYSTORE : String to encrypt = > Hello
07-28 11:27:35.119: I/System.out(22933): KEYSTORE : [B@41bbf4d0
07-28 11:27:38.422: I/System.out(22933): KEYSTORE : String to Decrypt = > UJGAchuDhu3mqH5YPjmYqKBapJYMjJRk9g6HIy8bANooWorzwqgiEo+dOse6Nfq7i0yzw/Wt7TSdTNiYROxehkZvEx/mW5+Niw1CgZ2y9b/ijTeNTF+7aGPrqfDXJ38hUFdTPc6oNl2FVOIafncGOSK9po1JOAYeK0JiA2KrACfPLPjsLQSRzseThyYGxttRM7qbx/N0VTmlTeuNpLFld8Gtw3fHR8UoLGkH/OTFYPLZBVNE8t/oCCy8FpcCu9SGXxF8vh1R4rq15bfyyh9sBU9RuVtoLM0wDSbKixHhNOwwx2Z/A+SHDaQD9C+x3p1AnS9FYZm0Y07E+VYQWqzOpw
07-28 11:27:38.562: W/System.err(22933): javax.crypto.BadPaddingException: error:0407106B:rsa routines:RSA_padding_check_PKCS1_type_2:block type is not 02
07-28 11:27:41.515: D/WifiNative-wlan0(773): doString: SIGNAL_POLL
07-28 11:27:41.515: W/WifiHW(773): QCOM Debug wifi_send_command "IFNAME=wlan0 SIGNAL_POLL"
07-28 11:27:41.525: D/wpa_supplicant(16189): nl80211: survey data missing!
07-2
07-28 11:27:56.612: W/WifiHW(773): QCOM Debug wifi_send_command "IFNAME=wlan0 SIGNAL_POLL"
07-28 11:27:56.612: D/wpa_supplicant(16189): nl80211: survey data missing!
07-28 11:27:56.622: I/wpa_supplicant(16189): environment dirty rate=0 [0][0][0]
07-28 11:27:56.622: D/WifiStateMachine(773): fetchRssiAndLinkSpeedNative RSSI = -62 abnormalRssiCnt = 0 newLinkSpeed = 58
07-28 11:27:56.622: D/WifiStateMachine(773): fetchRssiAndLinkSpeedNative mLinkspeedCount = 2, mLinkspeedSum: 116

我不确定哪里出错了.

推荐答案

当填充(填充太小的加密块的字节)不匹配指定格式(例如例如 PKCS1、OAEP、...).这可能有几个原因:

A BadPaddingException occurs when the padding (bytes to fill up a too small encryption block) doesn't match a specified format (for example PKCS1, OAEP, ...). This can have a few causes:

  1. 您正在使用不同的 RSA 模式进行加密和解密.
  2. 你从加密中得到的数据(字节[])与你传递给解密的数据不同.
  3. (您使用的密钥对不正确.)

由于您使用 getInstance("RSA") 初始化 RSA 进行加密，使用 getInstance("RSA/ECB/PKCS1Padding") 进行解密，因此可能ECB/PKCS1Padding 不是 Android 上的默认设置(即使它应该在 Desktop-Java 上).

Since you are initializing RSA with getInstance("RSA") for encryption and getInstance("RSA/ECB/PKCS1Padding") for decryption, it could be possible that ECB/PKCS1Padding is not the default on Android (even though it should be on Desktop-Java).

所以在 RSAEncrypt() 中试试这个:

So try this in RSAEncrypt():

cipher.getInstance("RSA/ECB/PKCS1Padding");

如果这不起作用，请确保将加密中从 cipher.doFinal() 获得的完全相同的 byte[] 传递给 cipher.doFinal()在解密中.

If this does not work, make sure that you pass the exact same byte[] you get from cipher.doFinal() in encryption to cipher.doFinal() in decryption.

(顺便说一句，你的代码在我的 Desktop Java7 上运行.)

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