Symmetric-Encrypt-Algorithm/Pseudocode.txt at main · Adam-ZS/Symmetric-Encrypt-Algorithm · GitHub

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# Pseudo-Code for the Proposed Algorithm

    1. Initialize S-Boxes and Permutation Patterns

       - S-Boxes ( 10 unique 16-element substitution boxes)

       - Permutation (Define 16-bit permutation pattern)

       - Generate Inverse S-Boxes for decryption.

       - Generate Inverse Permutation pattern.


    2. Function: Generate Subkeys

       INPUT: 16-bit Master Key

       OUTPUT: 4 Subkeys

       FOR i = 0 to 3:

           Rotate the key left by i bits.

           Store the result as a subkey.


    3. Function: Substitute Block

       INPUT: 16-bit Block, S-Box

       OUTPUT: Substituted 16-bit Block

       a. Split the block into 4 nibbles (4 bits each).

       b. Replace each nibble using the S-Box.

       c. Recombine substituted nibbles into a 16-bit block.


    4. Function: Permute Block

       INPUT: 16-bit Block, Permutation Pattern

       OUTPUT: Permuted 16-bit Block

       a. Rearrange the bits of the block based on the pattern.


    5. Function: Encrypt Block

       INPUT: 16-bit Plaintext Block, Subkeys

       OUTPUT: Ciphertext Block

       a. FOR round = 0 to 3:

           i. Apply S-Box substitution.

           ii. Apply bit permutation.

           iii. XOR the block with the current subkey.

       b. Return the resulting ciphertext block.


    6. Function: Decrypt Block

       INPUT: 16-bit Ciphertext Block, Subkeys

       OUTPUT: Plaintext Block

       a. FOR round = 3 to 0 (in reverse):

           i. XOR the block with the current subkey.

           ii. Apply inverse permutation.

           iii. Apply inverse S-Box substitution.

       b. Return the resulting plaintext block.


    7. Function: Convert String to Hex Blocks

       INPUT: Plaintext String

       OUTPUT: List of 16-bit Hexadecimal Blocks

       a. Convert each character to its hexadecimal representation.

       b. Group the hex values into 16-bit blocks.

       c. Pad the final block if necessary.


    8. Function: Convert Hex Blocks to String

       INPUT: List of Decrypted Hexadecimal Blocks

       OUTPUT: Plaintext String

       a. Convert each block into characters.

       b. Remove any padding.


    9. Main Encryption Process

       INPUT: Plaintext String, 16-bit Key

       OUTPUT: Ciphertext Blocks

       a. Generate subkeys using the master key.

       b. Convert plaintext to hex blocks.

       c. Encrypt each block using the `Encrypt Block` function.

       d. Return the list of ciphertext blocks.


    10. Main Decryption Process

        INPUT: Ciphertext Blocks, 16-bit Key

        OUTPUT: Plaintext String

        a. Generate subkeys using the master key.

        b. Decrypt each block using the `Decrypt Block` function.

        c. Convert decrypted blocks to a plaintext string.

        d. Return the plaintext string.


    11. End.