AES Cipher Encryption & Decryption with Example

AES Cipher (AES) is a symmetric encryption algorithm that converts plaintext (readable text) into ciphertext (unreadable text) using a secret key. 1. INPUTS Plaintext (ASCII → Hex) "Password Rama41S" plain text in Hex->50 61 73 73 77 6F 72 64 20 52 61 6D 61 34 31 53 Key "Tanav Bank Accnt" Key in Hex->54 61 6E 61 76 20 42 61 6E 6B 20 41 63 63 6E 74 AES-128 requires 16-byte plaintext and 16-byte key. 2. AES STATE (Column-wise) Plaintext State [ 50 77 20 61 61 6F 52 34 73 72 61 31 73 64 6D 53] Key State (K₀) [ 54 76 6E 63 61 20 6B 63 6E 42 20 6E 61 61 41 74] 3. Steps performed for encryption Plaintext │ ▼ Initial AddRoundKey │ ▼ Round 1 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼ Round 2 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼ Round 3 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼ Round 4 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼ Round 5 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼ Round 6 SubBytes → ShiftRows → MixColumns → AddRoundKey │ ▼