Cryptography is the science of protecting information by converting it into an unreadable form so that only authorized users can access it. It ensures confidentiality, integrity, authentication, and non-repudiation of data during transmission over insecure communication channels such as the Internet. The secure transmission of data using cryptography involves a sequence of well-defined steps that safeguard information from unauthorized access, modification, and impersonation. The process begins when the sender prepares the original information, known as plaintext. Plaintext may include text, images, files, financial records, or any digital information that needs protection. Before transmission, the sender and receiver agree upon a cryptographic algorithm and the required keys. Depending on the cryptographic system, either symmetric key cryptography or asymmetric key cryptography is used. In symmetric key cryptography, both the sender and receiver share the same secret encryption key. The sender applies an encryption algorithm such as the Advanced Encryption Standard (AES) to convert the plaintext into ciphertext. Ciphertext is an unreadable