S-DES Visualization

Step 1: Initial Permutation (IP)

Input Plaintext:

Permutation Table (IP):[2, 6, 3, 1, 4, 8, 5, 7]

Output after IP:

Step 2: Key Generation

Initial 10-bit Key:

Permutation P10:[3, 5, 2, 7, 4, 10, 1, 9, 8, 6]

After P10:

Left Shift 1 (LS-1) on left 5 bits:

Left Shift 1 (LS-1) on right 5 bits:

Combined after LS-1:

Permutation P8:[6, 3, 7, 4, 8, 5, 10, 9]

Subkey K1:

Left Shift 2 (LS-2) on LS-1 left bits:

Left Shift 2 (LS-2) on LS-1 right bits:

Combined after LS-2:

Permutation P8:[6, 3, 7, 4, 8, 5, 10, 9]

Subkey K2:

Step 3: Round 1 Function (f_k)

Input to Round 1 (Output of IP):

Subkey K1:

Function f_k Details:

Right Half Input:

Expansion/Permutation (E/P):[4, 1, 2, 3, 2, 3, 4, 1]

Output of E/P:

XOR with K1: XOR

XOR Result:

S-Box Input (S0 | S1):

S0 Output: | S1 Output:

Combined S-Box Output:

Permutation P4:[2, 4, 3, 1]

Output of P4 (Result of f_k):

Left Half Input:

XOR Left Half with P4 Output: XOR

XOR Result:

Output after Round 1 (Before Swap):

Step 4: Swap Halves

Input before Swap:

Output after Swap:

Step 5: Round 2 Function (f_k)

Input to Round 2 (Output of Swap):

Subkey K2:

Function f_k Details:

Right Half Input:

Expansion/Permutation (E/P):[4, 1, 2, 3, 2, 3, 4, 1]

Output of E/P:

XOR with K2: XOR

XOR Result:

S-Box Input (S0 | S1):

S0 Output: | S1 Output:

Combined S-Box Output:

Permutation P4:[2, 4, 3, 1]

Output of P4 (Result of f_k):

Left Half Input:

XOR Left Half with P4 Output: XOR

XOR Result:

Output after Round 2:

Step 6: Final Permutation (IP^-1)

Input to Final Permutation:

Permutation Table (IP^-1):[4, 1, 3, 5, 7, 2, 8, 6]

Final Ciphertext:

Result

Plaintext:

Key:

Ciphertext / Keys: