encode in windows decode in linux - decode

Question

I created (more or less rewrited from the net) the shortest possible program to encode and decode strings.
namespace crypto
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private static string Encrypt(string toEncrypt, bool useHashing)
{
byte[] keyArray;
byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);
System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
hashmd5.Clear();
}
else
keyArray = UTF8Encoding.UTF8.GetBytes(key);
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
tdes.Key = keyArray;
tdes.Mode = CipherMode.ECB;
tdes.Padding = PaddingMode.PKCS7;
ICryptoTransform cTransform = tdes.CreateEncryptor();
byte[] resultArray =
cTransform.TransformFinalBlock(toEncryptArray, 0,
toEncryptArray.Length);
tdes.Clear();
return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}
private static string Decrypt(string cipherString, bool useHashing)
{
byte[] keyArray;
byte[] toEncryptArray = Convert.FromBase64String(cipherString);
System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
hashmd5.Clear();
}
else
{
keyArray = UTF8Encoding.UTF8.GetBytes(key);
}
TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
tdes.Key = keyArray;
tdes.Mode = CipherMode.ECB;
tdes.Padding = PaddingMode.PKCS7;
ICryptoTransform cTransform = tdes.CreateDecryptor();
try
{
byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
return UTF8Encoding.UTF8.GetString(resultArray);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
return null;
}
finally
{
tdes.Clear();
}
}
private void button1_Click(object sender, EventArgs e)
{
this.rtfENC.Text = Encrypt(this.rtfDEC.Text, true);
this.rtfDEC.Text = "";
}
private void button2_Click(object sender, EventArgs e)
{
this.rtfDEC.Text = Decrypt(this.rtfENC.Text, true);
this.rtfENC.Text = "";
}
}
It has only two methods Decrypt and Encrypt and it works as I expect. I wonder IF I could create program/script with exactly the same functionality in Linux. Or maybe the better question HOW to do it? Is bash suitable for it ? Do I need any special/external libraries, packages ? Would it be difficult?

Answer 1

The method is not very secure.
3DES should not be used for new work, use AES.
If deriving a key MD5 is not secure, use PKBKDF2.
Do not use ECB mode, it is not secure, use CBC with a random iv, prepend the iv to the encrypted data.
Use a key of exactly the correct length, do not rely on any default padding.
Most languages include at least a few cryptographic functions and AES is the current standard. If possible find one that is FIPS certified and that has hardware support, reasonably current Intel chips have such support as do the A- series chips. Hardware support can eaisly be 500 to 1000 times faster.
The issue with scripting languages, and to some extent overall, is keeping the encryption key secure.
Finally, encryption by itself and/or not used with best practices does not create much security, mnore of a illusion of security.