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Android AESを使用した暗号化/復号化

暗号化と復号化 AndroidのAESで画像やその他のファイルを作成する方法の良い例はありますか？

javaandroidencryptionaes
100
hardartcore

警告：この回答には、安全でないため使用しないコードが含まれています（キーの導出にSHA1PRNGを使用し、ECBモードでAESを使用）

代わりに、PBCDF2WithHmacSHA1を使用して、キー派生とCBCまたはGCMモードのAESを使用します（GCMはプライバシーと整合性の両方を提供します）

次のような関数を使用できます。

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;
}

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);
    return decrypted;
}

そして、次のように呼び出します：

ByteArrayOutputStream baos = new ByteArrayOutputStream();  
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); // bm is the bitmap object   
byte[] b = baos.toByteArray();  

byte[] keyStart = "this is a key".getBytes();
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(keyStart);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] key = skey.getEncoded();    

// encrypt
byte[] encryptedData = encrypt(key,b);
// decrypt
byte[] decryptedData = decrypt(key,encryptedData);

これでうまくいくはずです。私は今、プロジェクトで同様のコードを使用しています。

128
Nacho L.
import Java.security.AlgorithmParameters;
import Java.security.SecureRandom;
import Java.security.spec.KeySpec;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

class SecurityUtils {

  private static final byte[] salt = { (byte) 0xA4, (byte) 0x0B, (byte) 0xC8,
      (byte) 0x34, (byte) 0xD6, (byte) 0x95, (byte) 0xF3, (byte) 0x13 };

  private static int BLOCKS = 128;

  public static byte[] encryptAES(String seed, String cleartext)
      throws Exception {
    byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
    SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
    return cipher.doFinal(cleartext.getBytes("UTF8"));
  }

  public static byte[] decryptAES(String seed, byte[] data) throws Exception {
    byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
    SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    return cipher.doFinal(data);
  }

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

  private static byte[] pad(byte[] seed) {
    byte[] nseed = new byte[BLOCKS / 8];
    for (int i = 0; i < BLOCKS / 8; i++)
      nseed[i] = 0;
    for (int i = 0; i < seed.length; i++)
      nseed[i] = seed[i];

    return nseed;
  }

  public static byte[] encryptPBE(String password, String cleartext)
      throws Exception {
    SecretKeyFactory factory = SecretKeyFactory
        .getInstance("PBKDF2WithHmacSHA1");
    KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 1024, 256);
    SecretKey tmp = factory.generateSecret(spec);
    SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");

    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, secret);
    AlgorithmParameters params = cipher.getParameters();
    byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
    return cipher.doFinal(cleartext.getBytes("UTF-8"));
  }

  public static String decryptPBE(SecretKey secret, String ciphertext,
      byte[] iv) throws Exception {
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
    return new String(cipher.doFinal(ciphertext.getBytes()), "UTF-8");
  }

}
13
Ashok Domadiya

Nacho.Lで述べたように、PBKDF2WithHmacSHA1派生はより安全であるため使用されます。

import Android.util.Base64;

import Java.security.NoSuchAlgorithmException;
import Java.security.spec.InvalidKeySpecException;
import Java.security.spec.KeySpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

public class AESEncyption {

    private static final int pswdIterations = 10;
    private static final int keySize = 128;
    private static final String cypherInstance = "AES/CBC/PKCS5Padding";
    private static final String secretKeyInstance = "PBKDF2WithHmacSHA1";
    private static final String plainText = "sampleText";
    private static final String AESSalt = "exampleSalt";
    private static final String initializationVector = "8119745113154120";

    public static String encrypt(String textToEncrypt) throws Exception {

        SecretKeySpec skeySpec = new SecretKeySpec(getRaw(plainText, AESSalt), "AES");
        Cipher cipher = Cipher.getInstance(cypherInstance);
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(initializationVector.getBytes()));
        byte[] encrypted = cipher.doFinal(textToEncrypt.getBytes());
        return Base64.encodeToString(encrypted, Base64.DEFAULT);
    }

    public static String decrypt(String textToDecrypt) throws Exception {

        byte[] encryted_bytes = Base64.decode(textToDecrypt, Base64.DEFAULT);
        SecretKeySpec skeySpec = new SecretKeySpec(getRaw(plainText, AESSalt), "AES");
        Cipher cipher = Cipher.getInstance(cypherInstance);
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(initializationVector.getBytes()));
        byte[] decrypted = cipher.doFinal(encryted_bytes);
        return new String(decrypted, "UTF-8");
    }

    private static byte[] getRaw(String plainText, String salt) {
        try {
            SecretKeyFactory factory = SecretKeyFactory.getInstance(secretKeyInstance);
            KeySpec spec = new PBEKeySpec(plainText.toCharArray(), salt.getBytes(), pswdIterations, keySize);
            return factory.generateSecret(spec).getEncoded();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return new byte[0];
    }

}
12
Abiranjan

古い質問ですが、以前のAndroidをサポートする回答をアップグレードして4.2を投稿し、 Androidデベロッパーブログ

さらに、 github repo に実際の例を残しています。

import Java.nio.charset.Charset;
import Java.security.AlgorithmParameters;
import Java.security.SecureRandom;

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

import org.Apache.commons.codec.binary.Base64;


/*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will Google be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, as long as the Origin is not misrepresented.
* 
* @author: Ricardo Champa
* 
*/

public class MyCipher {

    private final static String ALGORITHM = "AES";
    private String mySecret;

    public MyCipher(String mySecret){
        this.mySecret = mySecret;
    }

    public MyCipherData encryptUTF8(String data){
        try{
            byte[] bytes = data.toString().getBytes("utf-8");
            byte[] bytesBase64 = Base64.encodeBase64(bytes);
            return encrypt(bytesBase64);
        }
        catch(Exception e){
            MyLogs.show(e.getMessage());
            return null;
        }

    }

    public String decryptUTF8(byte[] encryptedData, IvParameterSpec iv){
        try {
            byte[] decryptedData = decrypt(encryptedData, iv);
            byte[] decodedBytes = Base64.decodeBase64(decryptedData);
            String restored_data = new String(decodedBytes, Charset.forName("UTF8"));
            return restored_data;
        } catch (Exception e) {
            MyLogs.show(e.getMessage());;
            return null;
        }
    }

    //AES
    private MyCipherData encrypt(byte[] raw, byte[] clear) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        //solved using PRNGFixes class
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] data = cipher.doFinal(clear);

        AlgorithmParameters params = cipher.getParameters();
        byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
        return new MyCipherData(data, iv);
    }

    private byte[] decrypt(byte[] raw, byte[] encrypted, IvParameterSpec iv) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
        byte[] decrypted = cipher.doFinal(encrypted);
        return decrypted;
    }

    private byte[] getKey() throws Exception{
        byte[] keyStart = this.mySecret.getBytes("utf-8");
        KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM);

        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
        //      if (Android.os.Build.VERSION.SDK_INT >= 17) {
        //          sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
        //      } else {
        //          sr = SecureRandom.getInstance("SHA1PRNG");
        //      }
        sr.setSeed(keyStart);
        kgen.init(128, sr); // 192 and 256 bits may not be available
        SecretKey skey = kgen.generateKey();
        byte[] key = skey.getEncoded();
        return key;

    }
    ////////////////////////////////////////////////////////////
    private MyCipherData encrypt(byte[] data) throws Exception{
        return encrypt(getKey(),data);
    }
    private byte[] decrypt(byte[] encryptedData, IvParameterSpec iv) throws Exception{
        return decrypt(getKey(),encryptedData, iv);
    }
}
9
Ricardo

テキストファイルを暗号化する場合は、次のテスト/サンプルが役立つ場合があります。次のことを行います。

  1. バイトストリームを作成し、
  2. それをAES暗号化でラップし、
  3. 次にテキスト処理でラップします

  4. 最後にバッファリングします

    // AESdemo

public class AESdemo extends Activity {
    boolean encryptionIsOn = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_aesdemo);
        // needs <uses-permission Android:name="Android.permission.WRITE_EXTERNAL_STORAGE" />
        String homeDirName = Environment.getExternalStorageDirectory().getAbsolutePath() +
                "/" + getPackageName();
        File file = new File(homeDirName, "test.txt");
        byte[] keyBytes = getKey("password");

        try {
            File dir = new File(homeDirName);
            if (!dir.exists())
                dir.mkdirs();
            if (!file.exists())
                file.createNewFile();

            OutputStreamWriter osw;

            if (encryptionIsOn) {
                Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
                SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");
                IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes);
                cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);

                FileOutputStream fos = new FileOutputStream(file);
                CipherOutputStream cos = new CipherOutputStream(fos, cipher);
                osw = new OutputStreamWriter(cos, "UTF-8");
            }
            else    // not encryptionIsOn
                osw = new FileWriter(file);

            BufferedWriter out = new BufferedWriter(osw);
            out.write("This is a test\n");
            out.close();
        }
        catch (Exception e) {
            System.out.println("Encryption Exception "+e);
        }

        ///////////////////////////////////
        try {
            InputStreamReader isr;

            if (encryptionIsOn) {
                Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
                SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, "AES");
                IvParameterSpec ivParameterSpec = new IvParameterSpec(keyBytes);
                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);

                FileInputStream fis = new FileInputStream(file);
                CipherInputStream cis = new CipherInputStream(fis, cipher);
                isr = new InputStreamReader(cis, "UTF-8");
            }
            else
                isr = new FileReader(file);

            BufferedReader in = new BufferedReader(isr);
            String line = in.readLine();
            System.out.println("Text read: <"+line+">");
            in.close();
        }
        catch (Exception e) {
            System.out.println("Decryption Exception "+e);
        }
    }

    private byte[] getKey(String password) throws UnsupportedEncodingException {
        String key = "";
        while (key.length() < 16)
            key += password;
        return key.substring(0, 16).getBytes("UTF-8");
    }
}
7
SoloPilot

AndroidでのAES暗号化/復号化

String encData= encrypt("keykey".getBytes("UTF-16LE"), ("0123000000000215").getBytes("UTF-16LE"));

String decData= decrypt("keykey",Base64.decode(encData.getBytes("UTF-16LE"), Base64.DEFAULT));

暗号化機能

private static String encrypt(byte[] key, byte[] clear) throws Exception
    {
        MessageDigest md = MessageDigest.getInstance("md5");
        byte[] digestOfPassword = md.digest(key);

        SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(clear);
        return Base64.encodeToString(encrypted,Base64.DEFAULT);
    }

復号化機能

private static String decrypt(String key, byte[] encrypted) throws Exception
    {
        MessageDigest md = MessageDigest.getInstance("md5");
        byte[] digestOfPassword = md.digest(key.getBytes("UTF-16LE"));

        SecretKeySpec skeySpec = new SecretKeySpec(digestOfPassword, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS7Padding");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decrypted = cipher.doFinal(encrypted);
        return new String(decrypted, "UTF-16LE");
    }

C＃でのAES暗号化/復号化

 static void Main(string[] args)
        {
            string enc = encryptAES("0123000000000215", "keykey");
            string dec = decryptAES(enc, "keykey");

            Console.ReadKey();
        }

暗号化機能

 public static string encryptAES(string input, string key)
        {
            var plain = Encoding.Unicode.GetBytes(input);

            // 128 bits
            AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
            provider.KeySize = 128;
            provider.Mode = CipherMode.ECB;
            provider.Padding = PaddingMode.PKCS7;

            provider.Key = CalculateMD5Hash(key);

            var enc = provider.CreateEncryptor().TransformFinalBlock(plain, 0, plain.Length);
            return Convert.ToBase64String(enc);
        }

復号化機能

public static string decryptAES(string encryptText, string key)
{
    byte[] enc = Convert.FromBase64String(encryptText);
    // 128 bits
    AesCryptoServiceProvider provider = new AesCryptoServiceProvider();
    provider.KeySize = 128;
    provider.Mode = CipherMode.ECB;
    provider.Padding = PaddingMode.PKCS7;

    provider.Key = CalculateMD5Hash(key);


    var dec = provider.CreateDecryptor().TransformFinalBlock(enc, 0, enc.Length);
    return Encoding.Unicode.GetString(dec);
}

md5を作成

 public static byte[] CalculateMD5Hash(string input)
        {
            MD5 md5 = MD5.Create();
            byte[] inputBytes = Encoding.Unicode.GetBytes(input);
            return md5.ComputeHash(inputBytes);
        }
5
MiladAhmadi

AndroidでAES暗号化を実行するシンプルなAPI。これは、AESCryptライブラリAndroidおよびObj-C（同じデフォルト）に対応するRubyに相当します。

https://github.com/scottyab/AESCrypt-Android

2
Hardip

AES/CBC/PKCS7暗号化/復号化の場合、次のコードをコピーして貼り付け、SecretKeyとIVを独自のSecretKeyに置き換えますIV。

import Java.io.UnsupportedEncodingException;
import Java.security.InvalidAlgorithmParameterException;
import Java.security.InvalidKeyException;
import Java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import Android.util.Base64;


public class CryptoHandler {

    String SecretKey = "xxxxxxxxxxxxxxxxxxxx";
    String IV = "xxxxxxxxxxxxxxxx";

    private static CryptoHandler instance = null;

    public static CryptoHandler getInstance() {

        if (instance == null) {
            instance = new CryptoHandler();
        }
        return instance;
    }

    public String encrypt(String message) throws NoSuchAlgorithmException,
            NoSuchPaddingException, IllegalBlockSizeException,
            BadPaddingException, InvalidKeyException,
            UnsupportedEncodingException, InvalidAlgorithmParameterException {

        byte[] srcBuff = message.getBytes("UTF8");
        //here using substring because AES takes only 16 or 24 or 32 byte of key 
        SecretKeySpec skeySpec = new 
        SecretKeySpec(SecretKey.substring(0,32).getBytes(), "AES");
        IvParameterSpec ivSpec = new 
        IvParameterSpec(IV.substring(0,16).getBytes());
        Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        ecipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec);
        byte[] dstBuff = ecipher.doFinal(srcBuff);
        String base64 = Base64.encodeToString(dstBuff, Base64.DEFAULT);
        return base64;
    }

    public String decrypt(String encrypted) throws NoSuchAlgorithmException,
            NoSuchPaddingException, InvalidKeyException,
            InvalidAlgorithmParameterException, IllegalBlockSizeException,
            BadPaddingException, UnsupportedEncodingException {

        SecretKeySpec skeySpec = new 
        SecretKeySpec(SecretKey.substring(0,32).getBytes(), "AES");
        IvParameterSpec ivSpec = new 
        IvParameterSpec(IV.substring(0,16).getBytes());
        Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        ecipher.init(Cipher.DECRYPT_MODE, skeySpec, ivSpec);
        byte[] raw = Base64.decode(encrypted, Base64.DEFAULT);
        byte[] originalBytes = ecipher.doFinal(raw);
        String original = new String(originalBytes, "UTF8");
        return original;
    }
}
2
Sujeet Kumar Gupta

私のために働いている以下のコードで試してください。

public static String decrypt（String encrypted）throws NoSuchAlgorithmException、NoSuchPaddingException、InvalidKeyException、InvalidAlgorithmParameterException、IllegalBlockSizeException、BadPaddingException、UnsupportedEncodingException {

    byte[] key = your Key in byte array;
    byte[] input = sault in byte array


    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
    IvParameterSpec ivSpec = new IvParameterSpec(input);
    Cipher ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    ecipher.init(Cipher.DECRYPT_MODE, skeySpec, ivSpec);
    byte[] raw = Base64.decode(encrypted, Base64.DEFAULT);
    byte[] originalBytes = ecipher.doFinal(raw);
    String original = new String(originalBytes, "UTF8");
    return original;
}
0
Rhn Bhadani

弾力のある城をAndroidプロジェクトに追加するには： https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk16/1.45

メインアクティビティに次の行を追加します。

static {
    Security.addProvider(new BouncyCastleProvider());
}

public class AESHelper {

    private static final String TAG = "AESHelper";

    public static byte[] encrypt(byte[] data, String initVector, String key) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES");
            c.init(Cipher.ENCRYPT_MODE, k, iv);
            return c.doFinal(data);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    public static byte[] decrypt(byte[] data, String initVector, String key) {
        try {
            IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
            Cipher c = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            SecretKeySpec k = new SecretKeySpec(Base64.decode(key, Base64.DEFAULT), "AES");
            c.init(Cipher.DECRYPT_MODE, k, iv);
            return c.doFinal(data);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    public static String keyGenerator() throws NoSuchAlgorithmException {
        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
        keyGenerator.init(192);

        return Base64.encodeToString(keyGenerator.generateKey().getEncoded(),
                Base64.DEFAULT);
    }
}
0
Matthew Hooker