java - 如何修复 javax.crypto.IllegalBlockSizeException？

Question

我已经使用 RSA 的公钥加密成功地加密了我的 AES key 。在使用 RSA 的私钥解密时，我得到:

javax.crypto.IllegalBlockSizeException

适用于我的加密逻辑是:

KeyGenerator keygen = KeyGenerator.getInstance("AES");
keygen.init(128);
SecretKey key = keygen.generateKey();
Log.d("keyS", encodeToString(key.getEncoded(), Base64.DEFAULT));
Calendar start = new GregorianCalendar();
Calendar stop = new GregorianCalendar();
stop.add(Calendar.YEAR,25);
KeyPairGeneratorSpec spec = new KeyPairGeneratorSpec.Builder(Objects.requireNonNull(getContext()))
        .setKeySize(2048)
        .setAlias(KEYSTORE_PROVIDER_ANDROID_KEYSTORE)
        .setSubject(new X500Principal("CN="+KEYSTORE_PROVIDER_ANDROID_KEYSTORE))
        .setSerialNumber(BigInteger.ZERO)
        .setStartDate(start.getTime()).setEndDate(stop.getTime()).build();
KeyPairGenerator keyPairGenerator;
KeyPair kp;
keyPairGenerator = KeyPairGenerator.getInstance("RSA", KEYSTORE_PROVIDER_ANDROID_KEYSTORE);
keyPairGenerator.initialize(spec);
kp = keyPairGenerator.generateKeyPair();
Cipher cipher = Cipher.getInstance("RSA/None/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, kp.getPublic());
String key64 = encodeToString(key.getEncoded(), Base64.DEFAULT);
editor.putString(SECRET,new String(cipher.doFinal(key64.getBytes()), StandardCharsets.UTF_8)).apply();
Log.d("key2",new String(cipher.doFinal(key64.getBytes()), StandardCharsets.UTF_8));

我目前使用的解密逻辑是:

final SharedPreferences settings = getSharedPreferences(SettingsActivity.PREF_SETTINGS, MODE_PRIVATE);
KeyStore keyStore = KeyStore.getInstance(KEYSTORE_PROVIDER_ANDROID_KEYSTORE);
keyStore.load(null);
KeyStore.Entry entry = keyStore.getEntry(KEYSTORE_PROVIDER_ANDROID_KEYSTORE,null);
PrivateKey privateKey = ((KeyStore.PrivateKeyEntry) entry).getPrivateKey();
Cipher cipher = Cipher.getInstance("RSA/None/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] tmp = Objects.requireNonNull(settings.getString(SECRET, null)).getBytes(StandardCharsets.UTF_8);
Log.d("key3",new String(tmp));
Log.d("key4", encodeToString(cipher.doFinal(tmp), Base64.DEFAULT) );

如何修复 cipher.doFinal() 抛出的错误？

Answer 1

找到我的解决方案。这是解决方案。感谢那些帮助我重新思考解决方案的人。加密代码:

KeyGenerator keygen = KeyGenerator.getInstance("AES");
keygen.init(128);
SecretKey key = keygen.generateKey();
Log.d("keyS", encodeToString(key.getEncoded(), Base64.DEFAULT));
Calendar start = new GregorianCalendar();
Calendar stop = new GregorianCalendar();
stop.add(Calendar.YEAR,25);
KeyPairGeneratorSpec spec = new KeyPairGeneratorSpec.Builder(Objects.requireNonNull(getContext()))
                            .setKeySize(2048)
                            .setAlias(KEYSTORE_PROVIDER_ANDROID_KEYSTORE)
                            .setSubject(new X500Principal("CN="+KEYSTORE_PROVIDER_ANDROID_KEYSTORE))
                            .setSerialNumber(BigInteger.ZERO)
                            .setStartDate(start.getTime()).setEndDate(stop.getTime()).build();
KeyPairGenerator keyPairGenerator;
KeyPair kp;
keyPairGenerator = KeyPairGenerator.getInstance("RSA", KEYSTORE_PROVIDER_ANDROID_KEYSTORE);
keyPairGenerator.initialize(spec);
kp = keyPairGenerator.generateKeyPair();
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, kp.getPublic());
               editor.putString(SECRET,encodeToString(cipher.doFinal(key.getEncoded()), Base64.DEFAULT)).apply();
Log.d("key2",encodeToString(cipher.doFinal(key.getEncoded()), Base64.DEFAULT));

解密代码:

final SharedPreferences settings = getSharedPreferences(SettingsActivity.PREF_SETTINGS, MODE_PRIVATE);
KeyStore keyStore = KeyStore.getInstance(KEYSTORE_PROVIDER_ANDROID_KEYSTORE);
keyStore.load(null);
KeyStore.Entry entry = keyStore.getEntry(KEYSTORE_PROVIDER_ANDROID_KEYSTORE,null);
PrivateKey privateKey = ((KeyStore.PrivateKeyEntry) entry).getPrivateKey();
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
String k64 = Objects.requireNonNull(settings.getString(SECRET, null));
byte[] tmp = decode(k64, Base64.DEFAULT);
Log.d("key3",k64);
MainActivity.key = new SecretKeySpec(cipher.doFinal(tmp),"AES");
Log.d("key4", encodeToString(MainActivity.key.getEncoded(),Base64.DEFAULT));