Password Encrypt and Decrypt Utility
June 28, 2011 Leave a comment
Password Encrypt and Decrypt Utility
Developing a secure application you need to apply security features, like securing your password. Explaining the how to encrypt and decrypt password. First create static class name is PasswordUtility. Here I am using SHA1 algorithm you can use the MD5 algorithm also. This is 16 bit encryption.
public static class PasswordUtility
{
private static string strPassPhrase = “pa$$w0rd”;// can be any string
private static string strSaltValue = “s@1tValue”;// can be any string
private static string strHashAlgorithm = “SHA1”;// can be “MD5”
private static int intPasswordIterations = 2; // can be any number
private static string strInitVector = “@1B2c3D4e5F6g7H8”;
// must be 16 bytes
private static int intKeySize = 128; // can be 192 or 128
// Here calling Encrypt method, the given string(password)
// Parameter string to encrypt
//return type is encrypted password
public static string Encrypt(string plainPassword)
{
return Encrypt(plainPassword, strPassPhrase, strSaltValue, strHashAlgorithm, intPasswordIterations, strInitVector, intKeySize);
}
// Encrypt the given string(password)
//Parameters are Password to encrypt,can be any string,can be any //string,MD5,no of iterations,must be 16 bytes,keysize 256,128 or 192
//Return type encrypted value
public static string Encrypt(string plainText,
string passPhrase,
string saltValue,
string hashAlgorithm,
int passwordIterations,
string initVector,
int keySize)
{
// Convert strings into byte arrays.
// Let us assume that strings only contain ASCII codes.
// If strings include Unicode characters, use Unicode, UTF7, or UTF8
// encoding.
byte[] byInitVectorBytes = Encoding.ASCII.GetBytes(strInitVector);
byte[] bySaltValueBytes = Encoding.ASCII.GetBytes(strSaltValue);
// Convert our plaintext into a byte array.
// Let us assume that plaintext contains UTF8-encoded characters.
byte[] byPlainTextBytes = Encoding.UTF8.GetBytes(plainText);
// First, we must create a password, from which the key will be derived.
// This password will be generated from the specified passphrase and
// salt value. The password will be created using the specified hash
// algorithm. Password creation can be done in several iterations.
PasswordDeriveBytes password = new PasswordDeriveBytes(
passPhrase,
bySaltValueBytes,
hashAlgorithm,
passwordIterations);
// Use the password to generate pseudo-random bytes for the encryption
// key. Specify the size of the key in bytes (instead of bits).
byte[] byKeyBytes = password.GetBytes(keySize / 8);
// Create uninitialized Rijndael encryption object.
RijndaelManaged symmetricKey = new RijndaelManaged();
// It is reasonable to set encryption mode to Cipher Block Chaining
// (CBC). Use default options for other symmetric key parameters.
symmetricKey.Mode = CipherMode.CBC;
// Generate encryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(
byKeyBytes,
byInitVectorBytes);
// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = new MemoryStream();
// Define cryptographic stream (always use Write mode for encryption).
CryptoStream cryptoStream = new CryptoStream(memoryStream,
encryptor,
CryptoStreamMode.Write);
// Start encrypting.
cryptoStream.Write(byPlainTextBytes, 0, byPlainTextBytes.Length);
// Finish encrypting.
cryptoStream.FlushFinalBlock();
// Convert our encrypted data from a memory stream into a byte array.
byte[] byCipherTextBytes = memoryStream.ToArray();
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert encrypted data into a base64-encoded string.
string strCipherText = Convert.ToBase64String(byCipherTextBytes);
// Return encrypted string.
return strCipherText;
}
//Calling Decrypts method the given string(password)
//Parameter is Encrypted string
//Retrun type is decrypted string
// If condition was added to check empty and null
public static string Decrypt(string encryptedPassword)
{
if (encryptedPassword == “” || encryptedPassword == null)
return string.Empty;
return Decrypt(encryptedPassword, strPassPhrase, strSaltValue, strHashAlgorithm, intPasswordIterations, strInitVector, intKeySize);
}
public static string Decrypt(string cipherText,
string passPhrase,
string saltValue,
string hashAlgorithm,
int passwordIterations,
string initVector,
int keySize)
{
// Convert strings defining encryption key characteristics into byte
// arrays. Let us assume that strings only contain ASCII codes.
// If strings include Unicode characters, use Unicode, UTF7, or UTF8
// encoding.
byte[] byInitVectorBytes = Encoding.ASCII.GetBytes(strInitVector);
byte[] bySaltValueBytes = Encoding.ASCII.GetBytes(strSaltValue);
// Convert our ciphertext into a byte array.
byte[] byCipherTextBytes = Convert.FromBase64String(cipherText);
// First, we must create a password, from which the key will be
// derived. This password will be generated from the specified
// passphrase and salt value. The password will be created using
// the specified hash algorithm. Password creation can be done in
// several iterations.
PasswordDeriveBytes password = new PasswordDeriveBytes(
passPhrase,
bySaltValueBytes,
hashAlgorithm,
passwordIterations);
// Use the password to generate pseudo-random bytes for the encryption
// key. Specify the size of the key in bytes (instead of bits).
byte[] byKeyBytes = password.GetBytes(keySize / 8);
// Create uninitialized Rijndael encryption object.
RijndaelManaged symmetricKey = new RijndaelManaged();
// It is reasonable to set encryption mode to Cipher Block Chaining
// (CBC). Use default options for other symmetric key parameters.
symmetricKey.Mode = CipherMode.CBC;
// Generate decryptor from the existing key bytes and initialization
// vector. Key size will be defined based on the number of the key
// bytes.
ICryptoTransform decryptor = symmetricKey.CreateDecryptor(
byKeyBytes,
byInitVectorBytes);
// Define memory stream which will be used to hold encrypted data.
MemoryStream memoryStream = new MemoryStream(byCipherTextBytes);
// Define cryptographic stream (always use Read mode for encryption).
CryptoStream cryptoStream = new CryptoStream(memoryStream,
decryptor,
CryptoStreamMode.Read);
// Since at this point we don’t know what the size of decrypted data
// will be, allocate the buffer long enough to hold ciphertext;
// plaintext is never longer than ciphertext.
byte[] byPlainTextBytes = new byte[byCipherTextBytes.Length];
// Start decrypting.
int iDecryptedByteCount = cryptoStream.Read(byPlainTextBytes, 0, byPlainTextBytes.Length);
// Close both streams.
memoryStream.Close();
cryptoStream.Close();
// Convert decrypted data into a string.
// Let us assume that the original plaintext string was UTF8-encoded.
string strPlainText = Encoding.UTF8.GetString(byPlainTextBytes, 0, iDecryptedByteCount);
// Return decrypted string.
return strPlainText;
}
}//Class ends here
You can call the these methods like this
PasswordUtility.Encrypt(strUserPwd)
PasswordUtility.Decrypt(strUserPwd)
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