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