在Android M和旧版本中使用KeyStore加密和解密用户名？

Question

我正在尝试使用KeyStore在应用程序中加密和解密用户名,

使用KeyPairGeneratorSpec在旧版本中创建密钥,如18到22,

KeyPairGeneratorSpec如被depricated android的M的23版本,但版本的Android M支持KeyGenParameterSpec.

此KeyGenParameterSpec是否支持向后兼容性或如何执行此操作？

我尝试了这样的事情,有没有更好的解决方案.现在工作正常!

在加密和解密的Ciper.getInstance时我需要这样做.是否有任何单个参数"RSA/ECB/OAEPWithSHA-256AndMGF1Padding"或"RSA/ECB/PKCS1Padding"我可以通过这两个版本？

if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
            c =  Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
        }else{
            c =  Cipher.getInstance("RSA/ECB/PKCS1Padding");
        }

下面的代码现在工作正常,让我知道如何改善这一点.

密钥生成器:

genkey(){
KeyPairGenerator generator = KeyPairGenerator .getInstance(KeyProperties.KEY_ALGORITHM_RSA, "AndroidKeyStore");
            if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
                TCLog.e(TAG,"Current version is 23(MashMello)");
                //Api level 23

                KeyGenParameterSpec spec = new  KeyGenParameterSpec.Builder(
                             keyName,
                            KeyProperties.PURPOSE_DECRYPT | KeyProperties.PURPOSE_ENCRYPT )
                            .setDigests(KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA512)
                            .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_OAEP)
                            .build();
                generator.initialize(spec);
            }else{
                TCLog.e(TAG,"Current version is < 23(MashMello)");
                //api level 17+ 4.4.3
                KeyPairGeneratorSpec spec = new KeyPairGeneratorSpec.Builder(getActivity())
                        .setAlias(keyName)
                        .setSubject(new X500Principal("CN=Sample Name, O=Android Authority"))
                        .setSerialNumber(BigInteger.ONE)
                        .setStartDate(start.getTime())
                        .setEndDate(end.getTime())
                        .build();
                generator.initialize(spec);
            }
           KeyPair keyPair = generator.generateKeyPair();
}

加密代码:

doEncription(){
 try {
        KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry) ks.getEntry(keyName, null);
        PublicKey publicKey = (PublicKey) privateKeyEntry.getCertificate().getPublicKey();
        Cipher c;
        if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
            c =  Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
        }else{
            c =  Cipher.getInstance("RSA/ECB/PKCS1Padding");
        }

        c.init(Cipher.ENCRYPT_MODE, publicKey);
        encodedUser = c.doFinal(userName.getBytes());
        encodedPassword = c.doFinal(userPassword.getBytes());

        userName = Base64.encodeToString(encodedUser, Base64.DEFAULT);
        userPassword = Base64.encodeToString(encodedPassword, Base64.DEFAULT);
        // Log.e("MainActivity","AES Encription Error.!");
    } catch (Exception e) {
        Log.e("MainActivity", "AES Encription Error.!");
    }
}

解密代码:

doDecryption(){
    try {
        KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry) ks.getEntry(keyName, null);
        PrivateKey privateKey = (PrivateKey) privateKeyEntry.getPrivateKey();

        Cipher c;
        if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
            c =  Cipher.getInstance("RSA/ECB/OAEPWithSHA-256AndMGF1Padding");
        }else{
            c =  Cipher.getInstance("RSA/ECB/PKCS1Padding");
        }
        c.init(Cipher.DECRYPT_MODE, privateKey);
        decodedUser = c.doFinal(encodedUser);
        decodedPassword = c.doFinal(encodedPassword);

    } catch (Exception e) {
        Log.e("MainActivity", "AES Decryption Error.!");
    }

}

Answer 1

密码变换取决于您为KeyGenParameterSpec或提供的参数KeyPairGeneratorSpec。"RSA/ECB/PKCS1Padding"如果您想在两种情况下使用（Android M及以下），请更改

spec.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_OAEP)

到

spec.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_RSA_PKCS1)

您可以使用以下代码检查哪些算法可用：

    Provider[] providers = Security.getProviders();
    for (Provider p : providers) {
        Log.d(TAG, "provider: " + p.getName());
        Set<Provider.Service> services = p.getServices();
        for (Provider.Service s : services) {
            Log.d(TAG, "--> algorithm: " + s.getAlgorithm());
        }
    }

我通过声明一个接口 IKeyStoreHandler 来避免编写大量 if-else，该接口提供所有必要的方法（添加/删除密钥、按别名列出所有密钥、获取私钥/公钥、解密/加密文本）并针对这两种情况实现它。