DES Calculator encrypt or decrypt test data values using DES block cipher. It takes a 64-bit (16 hex digit) data value and a 128-bit (32 hex digit) key. It can optionally provide a trace of the calculations performed, with varying degrees of detail.

You can use the DES Calculator applet displayed below to encrypt or decrypt using DES the specified 64-bit (16 hex digit) data value with the 64-bit (16 hex digit) key, with a trace of the calculations.

To use the calculator fill in the Input Data value (being 16 hexadecimal digits), and the DES Key (being 32 hexadecimal digits), and press either the Encrypt or Decrypt button, as required. The resulting value will be displayed, along with the trace of the calculation, at the level of detail specified by te Trace Level radio buttons. If there is an error in the supplied values, an error message will be displayed in red.

Encrypting the plaintext with the key should give the ciphertext, decrypting the ciphertext with the key should give the plaintext.

The provides details of:
1. the 64-bit (16 hex digit) key used (should be same as specified)
2. the 64-bit (16 hex digit) data value used (should be same as specified), and whether encrypt or decrypt has been requested
3. the left and right data halves after the initial permutation
4. for each of the 16 rounds, the 32-bit right half data value, the 48-bit (as 8 x 6-bit values) subkey, and the output of the non-linear function f which will be XOR'd with the left half data value (which was the right half in the previous round)
5. and the final value computed (being the en/decrypted original data value), after the final permutation, which should be as shown as the result.

Requirements:
* Java

The license of this software is Freeware, you can free download and free use this calculator software.