AES Encryption for Windows Phone

Question

Hi,
We are developing a windows phone app and the same app is also being developed in Android and IOS. All three platforms are using a JSON web service for data access. Parameters to be passed are encrypted using AES algorithm.
The web service uses the Encryption and Decryption as shown in the following link : 
https://msdn.microsoft.com/en-us/library/system.security.cryptography.aesmanaged(v=vs.110).aspx
The same is Encryption is available in IOS and Android and working fine.
I am unable to achieve the same encryption in Windows Phone as System.Security.Cryptography is not available in Windows Phone. I did browse around and found a few alternatives as shown below but i am not getting the desired result i.e. Encrypted data is
not the same and hence Decryption is not giving the same result in server side.
public static byte[] Encrypt(string plainText, string pw, string salt)
IBuffer pwBuffer = CryptographicBuffer.ConvertStringToBinary(pw, BinaryStringEncoding.Utf8);
IBuffer saltBuffer = CryptographicBuffer.ConvertStringToBinary(salt, BinaryStringEncoding.Utf16LE);
IBuffer plainBuffer = CryptographicBuffer.ConvertStringToBinary(plainText, BinaryStringEncoding.Utf16LE);
// Derive key material for password size 32 bytes for AES256 algorithm
KeyDerivationAlgorithmProvider keyDerivationProvider = Windows.Security.Cryptography.Core.KeyDerivationAlgorithmProvider.OpenAlgorithm("PBKDF2_SHA1");
// using salt and 1000 iterations
KeyDerivationParameters pbkdf2Parms = KeyDerivationParameters.BuildForPbkdf2(saltBuffer, 1000);
// create a key based on original key and derivation parmaters
CryptographicKey keyOriginal = keyDerivationProvider.CreateKey(pwBuffer);
IBuffer keyMaterial = CryptographicEngine.DeriveKeyMaterial(keyOriginal, pbkdf2Parms, 32);
CryptographicKey derivedPwKey = keyDerivationProvider.CreateKey(pwBuffer);
// derive buffer to be used for encryption salt from derived password key
IBuffer saltMaterial = CryptographicEngine.DeriveKeyMaterial(derivedPwKey, pbkdf2Parms, 16);
// display the buffers – because KeyDerivationProvider always gets cleared after each use, they are very similar unforunately
string keyMaterialString = CryptographicBuffer.EncodeToBase64String(keyMaterial);
string saltMaterialString = CryptographicBuffer.EncodeToBase64String(saltMaterial);
SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");
// create symmetric key from derived password key
CryptographicKey symmKey = symProvider.CreateSymmetricKey(keyMaterial);
// encrypt data buffer using symmetric key and derived salt material
IBuffer resultBuffer = CryptographicEngine.Encrypt(symmKey, plainBuffer, saltMaterial);
byte[] result;
CryptographicBuffer.CopyToByteArray(resultBuffer, out result);
return result;
public static string Decrypt(byte[] encryptedData, string pw, string salt)
IBuffer pwBuffer = CryptographicBuffer.ConvertStringToBinary(pw, BinaryStringEncoding.Utf8);
IBuffer saltBuffer = CryptographicBuffer.ConvertStringToBinary(salt, BinaryStringEncoding.Utf16LE);
IBuffer cipherBuffer = CryptographicBuffer.CreateFromByteArray(encryptedData);
// Derive key material for password size 32 bytes for AES256 algorithm
KeyDerivationAlgorithmProvider keyDerivationProvider = Windows.Security.Cryptography.Core.KeyDerivationAlgorithmProvider.OpenAlgorithm("PBKDF2_SHA1");
// using salt and 1000 iterations
KeyDerivationParameters pbkdf2Parms = KeyDerivationParameters.BuildForPbkdf2(saltBuffer, 1000);
// create a key based on original key and derivation parmaters
CryptographicKey keyOriginal = keyDerivationProvider.CreateKey(pwBuffer);
IBuffer keyMaterial = CryptographicEngine.DeriveKeyMaterial(keyOriginal, pbkdf2Parms, 32);
CryptographicKey derivedPwKey = keyDerivationProvider.CreateKey(pwBuffer);
// derive buffer to be used for encryption salt from derived password key
IBuffer saltMaterial = CryptographicEngine.DeriveKeyMaterial(derivedPwKey, pbkdf2Parms, 16);
// display the keys – because KeyDerivationProvider always gets cleared after each use, they are very similar unforunately
string keyMaterialString = CryptographicBuffer.EncodeToBase64String(keyMaterial);
string saltMaterialString = CryptographicBuffer.EncodeToBase64String(saltMaterial);
SymmetricKeyAlgorithmProvider symProvider = SymmetricKeyAlgorithmProvider.OpenAlgorithm("AES_CBC_PKCS7");
// create symmetric key from derived password material
CryptographicKey symmKey = symProvider.CreateSymmetricKey(keyMaterial);
// encrypt data buffer using symmetric key and derived salt material
IBuffer resultBuffer = CryptographicEngine.Decrypt(symmKey, cipherBuffer, saltMaterial);
string result = CryptographicBuffer.ConvertBinaryToString(BinaryStringEncoding.Utf16LE, resultBuffer);
return result;
public static string AES_Encrypt(string input, string pass)
SymmetricKeyAlgorithmProvider SAP = SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithmNames.AesEcbPkcs7);
CryptographicKey AES;
HashAlgorithmProvider HAP = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Md5);
CryptographicHash Hash_AES = HAP.CreateHash();
string encrypted = "";
try
byte[] hash = new byte[32];
Hash_AES.Append(CryptographicBuffer.CreateFromByteArray(System.Text.Encoding.UTF8.GetBytes(pass)));
byte[] temp;
CryptographicBuffer.CopyToByteArray(Hash_AES.GetValueAndReset(), out temp);
Array.Copy(temp, 0, hash, 0, 16);
Array.Copy(temp, 0, hash, 15, 16);
AES = SAP.CreateSymmetricKey(CryptographicBuffer.CreateFromByteArray(hash));
IBuffer Buffer = CryptographicBuffer.CreateFromByteArray(System.Text.Encoding.UTF8.GetBytes(input));
encrypted = CryptographicBuffer.EncodeToBase64String(CryptographicEngine.Encrypt(AES, Buffer, null));
return encrypted;
catch (Exception ex)
return null;
public static string AES_Decrypt(string input, string pass)
SymmetricKeyAlgorithmProvider SAP = SymmetricKeyAlgorithmProvider.OpenAlgorithm(SymmetricAlgorithmNames.AesEcbPkcs7);
CryptographicKey AES;
HashAlgorithmProvider HAP = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Md5);
CryptographicHash Hash_AES = HAP.CreateHash();
string decrypted = "";
try
byte[] hash = new byte[32];
Hash_AES.Append(CryptographicBuffer.CreateFromByteArray(System.Text.Encoding.UTF8.GetBytes(pass)));
byte[] temp;
CryptographicBuffer.CopyToByteArray(Hash_AES.GetValueAndReset(), out temp);
Array.Copy(temp, 0, hash, 0, 16);
Array.Copy(temp, 0, hash, 15, 16);
AES = SAP.CreateSymmetricKey(CryptographicBuffer.CreateFromByteArray(hash));
IBuffer Buffer = CryptographicBuffer.DecodeFromBase64String(input);
byte[] Decrypted;
CryptographicBuffer.CopyToByteArray(CryptographicEngine.Decrypt(AES, Buffer, null), out Decrypted);
decrypted = System.Text.Encoding.UTF8.GetString(Decrypted, 0, Decrypted.Length);
return decrypted;
catch (Exception ex)
return null;
Both methods shown above are not giving the same result.
I would require the following scenario :
Plain Text : "login@123"
Key : "0123456789abcdef"
IV : "fedcba9876543210"
Hex : 356F65678C82C137BDBB2A2C8F824A68
Encrypted Text : 5oegåÇ¡7Ωª*,èÇJh
Request you to please suggest alternative to obtain the same AES Encryption using a Key and IV in Windows Phone.
Thanks in advance.
Regards,
Vinay D

Answer 1

Hi,
The encryption and decryption in : http://dotnetspeak.com/2011/11/encrypting-and-decrypting-data-in-winrt-2 is
not giving me the desired result.
I would require the following scenario :
Plain Text : "login@123"
Key : "0123456789abcdef"
IV : "fedcba9876543210"
Encrypted Text : 5oegåÇ¡7Ωª*,èÇJh
But what i am getting from the above link is : 
I would require the following scenario :
Plain Text : "login@123"
Key : "0123456789abcdef"
IV : "fedcba9876543210"
Encrypted Text : NW9lZ4yCwTe9uyosj4JKaA==
As u can see the encrypted string is not the same and hence i would get a different decrypt string on the server.
I cannot change the server as it is in production and working with Android and IOS.
Regards,
Vinay D