Encryption and Decryption

priya mishra

11y1.6kVisual Basic .NET

i want to insert encrypted password into database and check the password from Decrypted password to login login.

Pls help me how to check encrypted password with decrypted password from database to login

6 Replies

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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;
}
Demir Acar11y ago
What's your lenght of your field ? increase your's field lenght if still continue your's method is wrong .
priya mishra11y ago
Hi,
my encryption code is working but at the time of decryption.This gives error :
Invalid length for a Base-64 char array or string.

My code is

public DataSet Add_CheckData()
{
System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
System.Text.Decoder passDecode = encoder.GetDecoder();
byte[] decodedPassword = Convert.FromBase64String(_Password);
int charCount = passDecode.GetCharCount(decodedPassword, 0, decodedPassword.Length);
char[] decodedChar = new char[charCount];
passDecode.GetChars(decodedPassword, 0, decodedPassword.Length, decodedChar, 0);
string result = new string(decodedChar);

SqlParameter[] p = new SqlParameter[]
{
new SqlParameter("@uname",_UserName),
new SqlParameter("@pwd",result)

};
return SqlHelper.ExecuteDataset(Obj_con.get_Connection(), CommandType.StoredProcedure, "SP_CheckData", p);

}
}
}
Sibeesh Venu11y ago
Hi ,
You can create those functions as mentioned in this articles.

http://www.codeproject.com/Articles/14150/Encrypt-and-Decrypt-Data-with-C
http://www.codeproject.com/Articles/5719/Simple-encrypting-and-decrypting-data-in-C

Please read those article , you will get complete idea behind encryption and decryption.

Please accept as answer if it helped you
Kindest Regards
Sibeesh
http://sibeeshpassion.com/
priya mishra11y ago
Is there is any method like convert.ToEncrypt() and Convert.ToDecrypt () to encrypt and decrypt data.
Pls tell me i am begineer
Thank you
Sibeesh Venu11y ago
HI Priya,
Please see the below links
http://www.aspsnippets.com/Articles/Encrypt-and-Decrypt-Username-or-Password-stored-in-database-in-ASPNet-using-C-and-VBNet.aspx

http://www.codeproject.com/Questions/304187/how-to-create-password-encrypt-decrypt-in-csharp

http://www.codeproject.com/Questions/304187/how-to-create-password-encrypt-decrypt-in-csharp

Please accept as answer if it helped you
Kindest Regards
Sibeesh
http://sibeeshpassion.com/