Problem in Encryption Decryption

Ravinder Reddy

Hi,
I am working on the Login screen. In my database I have USERNAME and PASSWORD in Encrypted format. From my Login screen I am reading the values (login name, password which are in plain text format) and I have to compare these values with the database values(which are in Encrypted format) How can I do this. Please help me out.

2 Replies

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Bikesh Srivastava10y ago
See this code to encrypt and decrypt username and password.
I have done already in my application ,its working fine .
privatestringEncrypt(stringclearText)
{
stringEncryptionKey="MAKV2SPBNI99212";
byte[]clearBytes=Encoding.Unicode.GetBytes(clearText);
using(Aesencryptor=Aes.Create())
{
Rfc2898DeriveBytespdb=newRfc2898DeriveBytes(EncryptionKey,newbyte[]{0x49,0x76,0x61,0x6e,0x20,0x4d,0x65,0x64,0x76,0x65,0x64,0x65,0x76});
encryptor.Key=pdb.GetBytes(32);
encryptor.IV=pdb.GetBytes(16);
using(MemoryStreamms=newMemoryStream())
{
using(CryptoStreamcs=newCryptoStream(ms,encryptor.CreateEncryptor(),CryptoStreamMode.Write))
{
cs.Write(clearBytes,0,clearBytes.Length);
cs.Close();
}
clearText=Convert.ToBase64String(ms.ToArray());
}
}
returnclearText;
}
privatestringDecrypt(stringcipherText)
{
stringEncryptionKey="MAKV2SPBNI99212";
byte[]cipherBytes=Convert.FromBase64String(cipherText);
using(Aesencryptor=Aes.Create())
{
Rfc2898DeriveBytespdb=newRfc2898DeriveBytes(EncryptionKey,newbyte[]{0x49,0x76,0x61,0x6e,0x20,0x4d,0x65,0x64,0x76,0x65,0x64,0x65,0x76});
encryptor.Key=pdb.GetBytes(32);
encryptor.IV=pdb.GetBytes(16);
using(MemoryStreamms=newMemoryStream())
{
using(CryptoStreamcs=newCryptoStream(ms,encryptor.CreateDecryptor(),CryptoStreamMode.Write))
{
cs.Write(cipherBytes,0,cipherBytes.Length);
cs.Close();
}
cipherText=Encoding.Unicode.GetString(ms.ToArray());
}
}
returncipherText;
}
mark as answer if resolve your problem.
Ananth G10y ago
Encryption
Sometimes we want to encrypt the values that time we use MD5 Encryption and Decryption
Here i give the code for Encryption and Decryption.
passPhrase ,saltValue ,initVector this variables are the key for Encryption and Decryption
public static string passPhrase = "YOUR KEY1";
public static string saltValue = "YOUR KE2";
public static string initVector = "YOUR KE3";

public static string FunForEncrypt(string objText)
{
int keySize = 256;
int passwordIterations = 03;
string hashAlgorithm = "MD5";
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(objText);
PasswordDeriveBytes password = new PasswordDeriveBytes
(
passPhrase,
saltValueBytes,
hashAlgorithm,
passwordIterations
);
byte[] keyBytes = password.GetBytes(keySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform encryptor = symmetricKey.CreateEncryptor
(
keyBytes,
initVectorBytes
);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream
(
memoryStream,
encryptor,
CryptoStreamMode.Write
);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
string cipherText = Convert.ToBase64String(cipherTextBytes);
cipherText = HttpUtility.UrlEncode(cipherText);
return cipherText;
}

Decryption :
this below code used to Decrypt the text
public static string FunForDecrypt(string cipherText)
{
string plainText = "";
int keySize = 256;
int passwordIterations = 03;
string hashAlgorithm = "MD5";
try
{
cipherText = HttpUtility.UrlDecode(cipherText);
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
PasswordDeriveBytes password = new PasswordDeriveBytes
(
passPhrase,
saltValueBytes,
hashAlgorithm,
passwordIterations
);
byte[] keyBytes = password.GetBytes(keySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
ICryptoTransform decryptor = symmetricKey.CreateDecryptor
(
keyBytes,
initVectorBytes
);
MemoryStream memoryStream = new MemoryStream(cipherTextBytes);
CryptoStream cryptoStream = new CryptoStream
(
memoryStream,
decryptor,
CryptoStreamMode.Read
);
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read
(
plainTextBytes,
0,
plainTextBytes.Length
);
memoryStream.Close();
cryptoStream.Close();
plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
catch (Exception ex)
{
plainText = "";
}
return plainText;
}