DES

Java implementation of DES for university cryptography course, only ECB mode is implemented (weak I know..)

Mostly used BigInteger class and String Manipulation to do bit operations

DES is the Data Encryption Standard, predecessor of the AES block cipher widely used today

It is 64-bit and as specified in FIPS Pub 46

To Run

Download the DES.java file

Open Terminal and cd into directory you downloaded to

eg. cd ~/Downloads/DES

Compile the java file

javac -c DES.java

Now you can run with

javaw DES.jar -k1 <key> -m <message_to_encrypt>

and the program will print the encrypted message to standard output

Options

To Decrypt simply add the -d option

eg. javaw DES.jar -d -k1 <key> -m <message_to_decrypt>

To use TripleDES encryption provide three keys like so:

javaw DES.jar -k1 <key1> -k2 <key2> -k3 <key3> -m <message_to_encrypt>

And for decryption again use -d:

javaw DES.jar -d -k1 <key1> -k2 <key2> -k3 <key3> -m <message_to_decrypt>