com.overset.dev» Blog Archive » Simple AES (Rijndael) C# Encrypt & Decrypt functions

4.17.08

Simple AES (Rijndael) C# Encrypt & Decrypt functions

I simply re-purposed Bobby Derosa’s Triple DES (3DES) Encrypt() and Decrypt() functions to provide a simple and straight-forward way to use AES symmetrical encryption safe for use on such things as UTF-8 and/or HTTP GET string compatibility. I’m using this in ASP.NET AJAX-enabled applications.

I’m only using a 256bit (32byte) key for these example functions.

Encrypt()

publicstaticstring Encrypt(string toEncrypt){
byte[] keyArray = UTF8Encoding.UTF8.GetBytes("12345678901234567890123456789012");
byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);
    RijndaelManaged rDel = new RijndaelManaged();

    rDel.Key = keyArray;

    rDel.Mode = CipherMode.ECB;

    rDel.Padding = PaddingMode.PKCS7;
    ICryptoTransform cTransform = rDel.CreateEncryptor();

    byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
    return Convert.ToBase64String(resultArray, 0, resultArray.Length);

}

Download this code: rijndael.encrypt.cs

Encrypt()

publicstaticstring Decrypt(string toDecrypt){
byte[] keyArray = UTF8Encoding.UTF8.GetBytes("12345678901234567890123456789012");
byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);
    RijndaelManaged rDel = new RijndaelManaged();

    rDel.Key = keyArray;

    rDel.Mode = CipherMode.ECB;

    rDel.Padding = PaddingMode.PKCS7;
    ICryptoTransform cTransform = rDel.CreateDecryptor();

    byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
    return UTF8Encoding.UTF8.GetString(resultArray);

}

Download this code: rijndael.decrypt.cs

No comments