Simplified Data Encryption Standard (S-DES) is a simple version of the DES Algorithm. It is similar to the DES algorithm but is a smaller algorithm and has fewer parameters than DES. It was made for educational purposes so that understanding DES would become simpler.
Enter 10-bit Master Key (using space)
1 0 0 1 0 0 0 0 0 1 0
KEY GENERATION..
After P10 Permutation: 1 0 0 0 0 0 1 1 0 0
After split,
l = 1 0 0 0 0
r = 0 1 1 0 0
After LeftShift-1,
l = 0 0 0 0 1
r = 1 1 0 0 0
After P8, Key-1: 1 0 1 0 0 1 0 0
After LeftShift-2,
l = 0 0 1 0 0
r = 0 0 0 1 1
After P8, Key-2: 0 1 0 0 0 0 1 1
_____________________________________________________________________________
Enter e for Encryption | Enter d for Decryption | Enter b for Both
b
Enter 8-bit Plain Text (using space)
1 0 0 1 0 1 1 1
ENCRYPTING..
After IP: 0 1 0 1 1 1 0 1
After split,
l = 0 1 0 1
r = 1 1 0 1
Round Function(fk)-1
After EP: 1 1 1 0 1 0 1 1
XOR with key
0 1 0 0 1 1 1 1
After Split
l = 0 1 0 0
r = 1 1 1 1
After S-Box: 1 1 1 1
After P4
1 1 1 1
XOR with leftarray
1 0 1 0
After combine
1 0 1 0 1 1 0 1
After Swap
l = 1 1 0 1
r = 1 0 1 0
Round Function(fk)-2
After EP: 0 1 0 1 0 1 0 1
XOR with key
0 0 0 1 0 1 1 0
After Split
l = 0 0 0 1
r = 0 1 1 0
After S-Box: 1 1 1 1
After P4
1 1 1 1
XOR with leftarray
0 0 1 0
After combine
0 0 1 0 1 0 1 0
After IP-Inverse, 8-bit Cipher Text is:
0 0 1 1 1 0 0 0
_____________________________________________________________________________
IP
0 0 1 0 1 0 1 0
Split
0 0 1 0
1 0 1 0
Round Function(fk)-1
After EP: 0 1 0 1 0 1 0 1
XOR with key
0 0 0 1 0 1 1 0
After Split
l = 0 0 0 1
r = 0 1 1 0
After S-Box: 1 1 1 1
After P4
1 1 1 1
XOR with leftarray
1 1 0 1
After combine
1 1 0 1 1 0 1 0
swap
1 0 1 0
1 1 0 1
Round Function(fk)-2
After EP: 1 1 1 0 1 0 1 1
XOR with key
0 1 0 0 1 1 1 1
After Split
l = 0 1 0 0
r = 1 1 1 1
After S-Box: 1 1 1 1
After P4
1 1 1 1
XOR with leftarray
0 1 0 1
After combine
0 1 0 1 1 1 0 1
After IP-Inverse, 8-bit Plain Text is:
1 0 0 1 0 1 1 1