java.security.InvalidKeyException：解密期间密钥大小错误

在解密期间，我得到"Wrong key size"或"Given final block not properly padded"的混合，取决于我正在运行的操作系统 .

在Win7上，使用IBMJCE或SUNJCE（两者都是Java8），解密在25％的时间内失败：

javax.crypto.BadPaddingException：在com.sun.crypto.provider.CipherCore.doFinal（CipherCore.java:811）的com.sun.crypto.provider.CipherCore.doFinal（CipherCore.java:676）中没有正确填充最终块 . ）at com.sun.crypto.provider.DESedeCipher.engineDoFinal（DESedeCipher.java:294）at javax.crypto.Cipher.doFinal（Cipher.java:2087）

在mac上，使用SUNJCE，解密在100％的时间内失败：

java.security.InvalidKeyException：com.sun.crypto.provider.DESedeCrypt.init（DESedeCrypt.java:69）的密钥大小错误，位于com的com.sun.crypto.provider.CipherBlockChaining.init（CipherBlockChaining.java：91） .sun.crypto.provider.CipherCore.init（CipherCore.java:469）at com.sun.crypto.provider.DESedeCipher.engineInit（DESedeCipher.java:197）at javax.crypto.Cipher.implInit（Cipher.java:791） ）在javax.crypto.Cipher.chooseProvider（Cipher.java:849）javax.crypto.Cipher.init（Cipher.java:1348）

使用DESEde，我相信密钥大小必须是24，我可以看到在Windows上，解密后，它总是24字节，而在mac上，它永远不会是24字节 .

这是起点 . 在decryptWithSymmetricKey期间始终抛出异常 . 注意，我对大部分代码（特定于DESede）进行了短循环，无法进一步缩小代码（非常新的安全空间） .

public static void runtest() throws Exception {
    String symmPad = "DESede/CBC/PKCS5Padding";
    String asymmPad = "RSA/ECB/OAEPWithSHA-256AndMGF1Padding";
    String pubKeyFp = "somekey";
    String stringToEncrypt = "abcdefg";

    KeyGenerator kgen = KeyGenerator.getInstance(DESEDE);
    kgen.init(112);
    SecretKey secKey = kgen.generateKey();

    String encryptedKey = encryptSymmetricKey(secKey, asymmPad);
    String encryptedData = encryptDataWithSymmetricKey(stringToEncrypt, secKey, symmPad);

    String decryptedKey = decryptWithPrivateKey(encryptedKey, pubKeyFp, asymmPad);
    String decryptedData = decryptWithSymmetricKey(encryptedData, decryptedKey, symmPad);
}

这里我们加密对称密钥，两个环境中的密钥长度为24

private static String encryptSymmetricKey(SecretKey secKey, String asymmPadding) throws Exception {
    KeyPair keyPair = getKeyPair("self4");
    Cipher cipher = Cipher.getInstance(asymmPadding);

    OAEPParameterSpec ospec = new OAEPParameterSpec(SHA256, MGF1, MGF1ParameterSpec.SHA256, PSource.PSpecified.DEFAULT);
    cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic(), ospec);

    String secKeyEncoded = new String(secKey.getEncoded());
    byte[] encrypted = cipher.doFinal(secKeyEncoded.getBytes());

    char[] encoded = Hex.encodeHex(encrypted);
    return new String(encoded);
}

在这里，我们使用对称密钥加密我们的字符串

private static String encryptDataWithSymmetricKey(String data, SecretKey secretKey, String symmPadding) throws Exception {
    Cipher cipher = Cipher.getInstance(symmPadding);
    IvParameterSpec iv = new IvParameterSpec(new byte[8]);
    cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

    byte[] encrypted = cipher.doFinal(data.getBytes());
    char[] encoded = Hex.encodeHex(encrypted);
    return new String(encoded);
}

解密和解码对称密钥是我第一次看到mac上的可变长度密钥 .

public String decryptWithPrivateKey(String encryptedData, String pubKeyFp, String asymmPadding) throws Exception {
    loadKeystores();
    String alias = fingerPrintAliasMap.get(pubKeyFp);

    KeyPair keyPair = getKeyPair(alias);
    Cipher cipher = Cipher.getInstance(asymmPadding);

    OAEPParameterSpec oParamSpec = new OAEPParameterSpec(SHA256, MGF1, MGF1ParameterSpec.SHA256, PSource.PSpecified.DEFAULT);
    cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate(), oParamSpec);

    byte[] decoded = Hex.decodeHex(encryptedData.toCharArray());
    byte[] decrypted = cipher.doFinal(decoded);
    System.out.println("decoded and decrypted key length: " + decrypted.length); // 24 on windows, random on mac

    return new String(Hex.encodeHex(decrypted));
}

失败发生在这里 - 在Windows上，它在cipher.doFinal 25％的时间内失败，在mac上，它在100％的时间在cipher.init失败 .

public String decryptWithSymmetricKey(String encryptedHexData, String symmKey, String symmPadding) throws Exception {

    byte[] key = Hex.decodeHex(symmKey.toCharArray());
    SecretKey skeySpec = new SecretKeySpec(key, DESEDE);
    IvParameterSpec iv = new IvParameterSpec(new byte[8]);

    Cipher cipher = Cipher.getInstance(symmPadding);
    cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv); // mac: Wrong key size

    byte[] decoded = Hex.decodeHex(encryptedHexData.toCharArray());
    byte[] deciphered = cipher.doFinal(decoded); // windows: Given final block not properly padded

    return new String(deciphered);
}

我假设如果我在mac上解决这个问题，它也应该在Windows上解决它 .