Update readme

Readme.md

@@ -1 +1,15 @@
-#DataEncrypter
+# DataEncrypter
+*DataEncrypter* is an easy to use tool for encryption and decryption. It is build to be lightweight and not memory intensive. It currently has a custom implementation of the Advanced Encryption Standard, but is open to be used with different algorithms as well, if they implement the ICryptMethod interface.
+
+File encryption by using the SecureFile class is very simple to handle. Files are saved as .secf (SECureFile) and provide a encrypted header with previous filename and extension, to restore the file completely after decryption.
+
+Basic usage of SecureFile:
+```C#
+  var secureFile = new SecureFile(path, key);
+
+  //Handles Memory and feeds the algorithms the correct data
+  secureFile.Encrypt();
+  secureFile.Decrypt();
+
+  secureFile.Save(newPath); //saves the file
+```