SDES Encryption Example with K1 = 00010011, K2 = 00100100, and Plaintext = 00100011

First, let's convert all the given numbers into binary:

K1 = 00010011 K2 = 00100100 Plaintext = 00100011

Now, let's apply the SDES encryption process:

1. Initial Permutation (IP) We apply the initial permutation to the plaintext: 00100011 -> 10000110

2. Round 1 We use K1 as the key for the first round. We split the output of the IP into two halves: L0 and R0, each with 4 bits. Then, we apply the following operations:

• Expansion/Permutation (EP) on R0: 01000100
• XOR with K1: 01010111
• Split into two halves: 0101 and 0111
• Apply S0 and S1 substitution boxes: S0(0101) = 0010 and S1(0111) = 1010
• Concatenate the outputs of the S-boxes: 00101010
• Apply a Permutation/Transposition (P4) to obtain the output of round 1: 10100001

3. Round 2 We use K2 as the key for the second round. We split the output of round 1 into two halves: L1 and R1, each with 4 bits. Then, we apply the following operations:

• Expansion/Permutation (EP) on R1: 10001000
• XOR with K2: 10101100
• Split into two halves: 1010 and 1100
• Apply S0 and S1 substitution boxes: S0(1010) = 1001 and S1(1100) = 0000
• Concatenate the outputs of the S-boxes: 10010000
• Apply a Permutation/Transposition (P4) to obtain the final ciphertext: 00001001

4. Final Permutation (IP-1) We apply the final permutation to the output of round 2: 00001001 -> 01000010

Therefore, the encrypted ciphertext is 01000010.