In cryptography, the Advanced Encryption Standard (AES) is a symmetric-key encryption standard. This standard comprises three block ciphers, AES-128, AES-192 and AES-256, adopted from a larger collection originally published as Rijndael. Each of these ciphers has a 128-bit block size, with key sizes of 128, 192 and 256 bits.

What Is Encryption?

Encryption is the process of changing data into a form that can be read only by the intended receiver. To decipher the message, the receiver of the encrypted data must have the proper decryption key (password). In traditional encryption schemes, the sender and the receiver use the same key to encrypt and decrypt data. In this case the key is the password you supply.

Example Uses For Encryption

Many modern day systems process data which is considered sensitive. For example, doctors store patient information, stock brokers store client financial data and home computer users store personal information on their computers — their own personal information. All this information is vulnerable to exposure in the event of the theft of the computer itself.

Should you find yourself fortunate enough to be developing software in C# then you may find the following code snippets beneficial.

Helper:

public static string Encrypt(string PlainText, string Password, string Salt, string HashAlgorithm, int PasswordIterations, string InitialVector, int KeySize)
{
try
{
byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
byte[] PlainTextBytes = Encoding.UTF8.GetBytes(PlainText);
PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.Mode = CipherMode.CBC;
ICryptoTransform Encryptor = SymmetricKey.CreateEncryptor(KeyBytes, InitialVectorBytes);
MemoryStream MemStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(MemStream, Encryptor, CryptoStreamMode.Write);
cryptoStream.Write(PlainTextBytes, 0, PlainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] CipherTextBytes = MemStream.ToArray();
MemStream.Close();
cryptoStream.Close();
MemStream.Dispose();
cryptoStream.Dispose();
Encryptor.Dispose();
return Convert.ToBase64String(CipherTextBytes);
}
catch (Exception ex)
{
throw ex;
}
}

Implementation:

Encrypt("mykey", "mypassword", "mysalt", "MD5",5, "qwertyuiqwertyui", 256);

Helper:

public static string Decrypt(string CipherText, string Password, string Salt, string HashAlgorithm, int PasswordIterations, string InitialVector, int KeySize)
{
try
{
byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
byte[] CipherTextBytes = Convert.FromBase64String(CipherText);
PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.Mode = CipherMode.CBC;
ICryptoTransform Decryptor = SymmetricKey.CreateDecryptor(KeyBytes, InitialVectorBytes);
MemoryStream MemStream = new MemoryStream(CipherTextBytes);
CryptoStream cryptoStream = new CryptoStream(MemStream, Decryptor, CryptoStreamMode.Read);
byte[] PlainTextBytes = new byte[CipherTextBytes.Length];
int ByteCount = cryptoStream.Read(PlainTextBytes, 0, PlainTextBytes.Length);
MemStream.Close();
cryptoStream.Close();
MemStream.Dispose();
cryptoStream.Dispose();
Decryptor.Dispose();
return Encoding.UTF8.GetString(PlainTextBytes, 0, ByteCount);
}
catch (Exception ex)
{
throw ex;
}
}

Implementation:

Decrypt("ND5lYPo4czOk5ZT7KNmU2Q==", "mypassword", "mysalt", "MD5",5, "qwertyuiqwertyui", 256);

There you have it. Now there is no reason to secure your sensitive data.