android sharedpreference怎样进行数据加密

在Android中，SharedPreferences本身不提供内置的数据加密功能。但是，您可以在将数据存储到SharedPreferences之前对其进行加密，并在从SharedPreferences读取数据时进行解密。以下是一个使用AES加密和解密的示例：

首先，您需要添加加密库，例如：

implementation 'com.google.crypto:crypto-commons:1.1.1'

然后，您可以使用以下代码进行加密和解密：

import android.content.Context;
import android.security.keystore.KeyGenParameterSpec;
import android.security.keystore.KeyProperties;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.UnrecoverableKeyException;
import java.util.Base64;

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

public class EncryptionHelper {

    private static final String KEY_ALIAS = "my_key_alias";
    private static final String TRANSFORMATION = "AES";

    public static SecretKey getSecretKey(Context context) throws NoSuchAlgorithmException, UnrecoverableKeyException {
        KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
        keyStore.load(null);

        if (!keyStore.containsAlias(KEY_ALIAS)) {
            KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
            KeyGenParameterSpec keyGenParameterSpec = new KeyGenParameterSpec.Builder(
                    KEY_ALIAS, KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
                    .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
                    .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
                    .build();
            keyGenerator.init(keyGenParameterSpec);
            keyGenerator.generateKey();
        }

        return (SecretKey) keyStore.getKey(KEY_ALIAS, null);
    }

    public static String encrypt(String data, SecretKey secretKey) throws Exception {
        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encryptedBytes = cipher.doFinal(data.getBytes(StandardCharsets.UTF_8));
        return Base64.getEncoder().encodeToString(encryptedBytes);
    }

    public static String decrypt(String encryptedData, SecretKey secretKey) throws Exception {
        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] decodedBytes = Base64.getDecoder().decode(encryptedData);
        byte[] decryptedBytes = cipher.doFinal(decodedBytes);
        return new String(decryptedBytes, StandardCharsets.UTF_8);
    }
}

现在，您可以使用EncryptionHelper类来加密和解密数据：

try {
    Context context = getApplicationContext();
    SecretKey secretKey = EncryptionHelper.getSecretKey(context);

    String originalData = "Hello, World!";
    String encryptedData = EncryptionHelper.encrypt(originalData, secretKey);
    String decryptedData = EncryptionHelper.decrypt(encryptedData, secretKey);

    System.out.println("Original Data: " + originalData);
    System.out.println("Encrypted Data: " + encryptedData);
    System.out.println("Decrypted Data: " + decryptedData);
} catch (Exception e) {
    e.printStackTrace();
}

请注意，这个示例使用了Android KeyStore系统来生成和存储密钥。这样，即使设备受到攻击，密钥也不会轻易泄露。