Decryption Output has strange symbols - android

I am working on encrypting (and later decrypting) strings in .Net and Java (on Android), using AES encryption , in the .Net side every thing is OK, in the Android(Java) side the output string of the posted code has unknown symbols.
String stdiv = "1234567890123456";
String txtinput = txtview1.getText().toString();
String mainkey = "0000999988887777";
byte[] key;
key = mainkey.getBytes("UTF8");
byte[] iv = stdiv.getBytes("UTF8");
byte[] input = txtinput.getBytes("UTF8");
Cipher cipher;
cipher = Cipher.getInstance("AES/CBC/PKCS7PADDING");
SecretKeySpec keyspec = new SecretKeySpec(key, "AES" );
IvParameterSpec paramspec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, keyspec, paramspec);
byte[] result = cipher.doFinal(input);
String str=new String(result,"UTF8");
txtview2.setText(str);

Related

Cross platform AES/CBC encryption decryption between openssl C and android

I just want AES/CBC 128 bit encryption decryption in openSSl c and Android with identical result.
I have to send encrypted data using pre defined 16 bytes key from android to c via bluetooth.
So is there any common mechanism which i can use in both to produce identical result of encryption and decryption.
Any help would be appreciate.
Thank you.
I found a solution which work perfectly for Android.
I am going to post the answer if it would help anyone.
static String IV = "AAAAAAAAAAAAAAAA";
static String encryptionKey = "0123456789ABCDEF";
public static String decrypt(byte[] cipherText, String encryptionKey) throws Exception{
Cipher cipher = Cipher.getInstance("AES/CBC/ZeroBytePadding"/*, "SunJCE"*/);
SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
cipher.init(Cipher.DECRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
return new String(cipher.doFinal(cipherText),"UTF-8");
}
public static byte[] encrypt(String plainText, String encryptionKey) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/ZeroBytePadding"/*, "SunJCE"*/);
SecretKeySpec key = new SecretKeySpec(encryptionKey.getBytes("UTF-8"), "AES");
cipher.init(Cipher.ENCRYPT_MODE, key,new IvParameterSpec(IV.getBytes("UTF-8")));
return cipher.doFinal(plainText.getBytes("UTF-8"));
}
//To Encrypt
byte[] cipher = encrypt(plaintext, encryptionKey);
System.out.print("cipher: ");
//To Decrypt
String decrypted = decrypt(cipher, encryptionKey);
System.out.println("decrypt: " + decrypted);

How to encrypt without a random number in Android

I currently have an accessory that uses AES/CBC without a random number on the key. Instead, the message itself includes a random number and the key is hard-coded. I'm trying to do the same thing on my Android to exchange with the accessory through BLE. Somehow I can't figure out how generate a Key-class object without using a random number.
Here's an example of what I'd like to be able to do:
public byte[] encrypt(byte[] key, byte[] input) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding ");
cipher.init(Cipher.ENCRYPT_MODE, key);
return cipher.doFinal(input);
}
Here's what I've tried:
public byte[] encrypt(byte[] key, byte[] input) throws Exception {
KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
SecureRandom secureRandom = new SecureRandom(key);
secureRandom.setSeed(key);
keyGenerator.init(128, secureRandom);
SecretKey secretkey = keyGenerator.generateKey();
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding ");
cipher.init(Cipher.ENCRYPT_MODE, secretkey);
return cipher.doFinal(input);
}
public byte[] encrypt(byte[] key, byte[] input) throws Exception {
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES/CBC/NoPadding ");
Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding ");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
return cipher.doFinal(input);
}
Unfortunately both of those alter the key before the encryption.
How can I use my key "as is"?
If you want to encrypt with your own key without salt or using any random, you can do as following.
byte[] keyBuf= new byte[32];
byte[] b= key.getBytes("UTF-8");
int len= b.length;
if (len > keyBuf.length) len = keyBuf.length;
System.arraycopy(b, 0, keyBuf, 0, len);
SecretKey keySpec = new SecretKeySpec(keyBuf, "AES");
byte[] ivBuf= new byte[16];
IvParameterSpec ivSpec = new IvParameterSpec(ivBuf);
cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);
Where key is my custom key as a String and b my key as a bytes[]. Initializing the cipher this way avoid the salting and allow you to always use your own key to encrypt anything.

RC2 and PKCS7 Encryption in iOS and Android

I'm trying to encrypt data using RC2 algorithm with PKCS7 padding in Android and iOS, but results are different.
I need to get the exact results. The KEY and IV are already provided but I'm not sure what to do with them. I need to get the same result as the codes in ios.
Values for
IV = "11223344"
KEY = "Sample"
IOS Code:
NSString *iv = IV ;
NSData *data = [s dataUsingEncoding:NSASCIIStringEncoding];
//key
NSString *key = KEY;
const char *keyPtr = [key cStringUsingEncoding:NSASCIIStringEncoding];
const char *cIv = [iv cStringUsingEncoding:NSASCIIStringEncoding];
NSUInteger dataLength = [data length];
size_t bufferSize = dataLength + kCCBlockSizeRC2;
void *buffer = malloc(bufferSize);
//kCCBlockSizeAES128
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmRC2,
kCCOptionPKCS7Padding,keyPtr,
[key length],
cIv,
[data bytes],
dataLength,
buffer,
bufferSize,
&numBytesEncrypted);
Android Code:
SecretKeySpec skeySpec = new SecretKeySpec(Constant.RC2_KEY.getBytes("US-ASCII"), "PBEWITHSHAAND128BITRC2-CBC");
IvParameterSpec iv = new IvParameterSpec(Constant.RC2_IV.getBytes("US-ASCII"));
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = cipher.doFinal(data);
return encrypted;
With this code, the cipher.init() does not execute and it results to an error. but when i change "AES/CBC/PKCS7Padding" or "AES/CBC/PKCS5Padding" to "PBEWITHSHAAND128BITRC2-CBC" it doesn't. It encrypts the data but different from the ios code's result.
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
Can anyone please help me solve this encryption thingy?
Your Java code looks quite broken - you certainly don't want to be referencing AES as your algorithm.
The following code will use RC2 correctly. I don't have the capability to test your iOS code, so perhaps there are other problems too.
byte[] iv = "87654321".getBytes("US-ASCII");
byte[] key = "SampleKey".getBytes("US-ASCII");
byte[] data = new byte[30]; // for example
SecretKeySpec skeySpec = new SecretKeySpec(key, "RC2");
RC2ParameterSpec ivSpec = new RC2ParameterSpec(key.length * 8, iv);
Cipher cipher = Cipher.getInstance("RC2/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec);
byte[] encrypted = cipher.doFinal(data);
// ....
Note the use of RC2ParameterSpec, which is required by the algorithm, plus the reference to PKCS5Padding rather than PKCS7Padding.

How to Encrypt String with special characters in android?

I need to encrypt the username and password and encode them and send it via SOAP header.
I used DES algorithm to encrypt the plainText `
String key = "qwer1234qwetr123wqw";
String x = "sadgsagd:%%^%ghsagdh";
byte[] keyBytes = new byte[1024];
byte[] plaintext = x.getBytes();
byte[] tdesKeyData = key.getBytes();
Cipher c3des = Cipher.getInstance("DESede/CBC/PKCS5Padding");
SecretKeySpec myKey = new SecretKeySpec(tdesKeyData, "DESede");
IvParameterSpec ivspec = new IvParameterSpec(keyBytes);
c3des.init(Cipher.ENCRYPT_MODE, myKey, ivspec);
byte[] cipherText = c3des.doFinal(plaintext);
int hash = Base64.encode(cipherText).hashCode();
return Base64.encode(cipherText);`
At runtime i am getting an Exception:
javax.crypto.BadPaddingException: Given
if you are using byte buffer of 64,i probably is too long change it to 32,
or use the length of file like this byte[] buffer = new byte[(int)new File("data").length()];
my problem get solved after doing this..

Encryption that works equally for iPhone and Android

I am trying to write an encryption class that will allow iPhone to send encrypted text to Android and vice versa. While this is quite straightforward in Android (following code)
private static final String CIPHER_ALGORITHM = "AES";
private static final String RANDOM_GENERATOR_ALGORITHM = "SHA1PRNG";
private static final int RANDOM_KEY_SIZE = 128;
// Encrypts string and encode in Base64
public static String encrypt( String password, String data ) throws Exception
{
byte[] secretKey = generateKey( password.getBytes() );
byte[] clear = data.getBytes();
SecretKeySpec secretKeySpec = new SecretKeySpec( secretKey, CIPHER_ALGORITHM );
Cipher cipher = Cipher.getInstance( CIPHER_ALGORITHM );
cipher.init( Cipher.ENCRYPT_MODE, secretKeySpec );
byte[] encrypted = cipher.doFinal( clear );
String encryptedString = Base64.encodeToString( encrypted, Base64.DEFAULT );
return encryptedString;
}
// Decrypts string encoded in Base64
public static String decrypt( String password, String encryptedData ) throws Exception
{
byte[] secretKey = generateKey( password.getBytes() );
SecretKeySpec secretKeySpec = new SecretKeySpec( secretKey, CIPHER_ALGORITHM );
Cipher cipher = Cipher.getInstance( CIPHER_ALGORITHM );
cipher.init( Cipher.DECRYPT_MODE, secretKeySpec );
byte[] encrypted = Base64.decode( encryptedData, Base64.DEFAULT );
byte[] decrypted = cipher.doFinal( encrypted );
return new String( decrypted );
}
public static byte[] generateKey( byte[] seed ) throws Exception
{
KeyGenerator keyGenerator = KeyGenerator.getInstance( CIPHER_ALGORITHM );
SecureRandom secureRandom = SecureRandom.getInstance( RANDOM_GENERATOR_ALGORITHM );
secureRandom.setSeed( seed );
keyGenerator.init( RANDOM_KEY_SIZE, secureRandom );
SecretKey secretKey = keyGenerator.generateKey();
return secretKey.getEncoded();
}
}
I have seen tens of answers on similar topics but did not get a really working piece of code for iOS that gives identical results. Most of the pieces of code don't even compile properly. Does somebody has a real working piece of code for that?
See RNCryptor on iOS, and JNCryptor for Java. They implement the same file format. It correctly handles AES-CBC-256 with a random IV, PBKDF2 generated passwords with random salt, and validated HMAC for data authentication and integrity.

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