Encryption is the two-way process of converting plaintext (normally readable data) into ciphertext (encrypted data) using an algorithm that can be reversed back into its original format using a specific secret key. The purpose of encryption is to protect the confidentiality and integrity of information. In simpler terms, encryption takes information and scrambles it in a way that only authorized parties with the correct key can unscramble and read it. It ensures that if someone intercepts or gains unauthorized access to the encrypted data, they won't be able to understand or make sense of it.

Types of Encryption

1. Symmetric: In symmetric encryption, the same key is used for both the encryption and decryption processes. Two parties can share a message using a shared key without worrying about unauthorized access, as long as the key remains secret. Symmetric keys: The key's secrecy is of the utmost importance. If the key is exposed, anyone can decrypt the encrypted data. Therefore, the key must be securely shared between the sender and receiver. Popular symmetric encryption algorithm - AES: AES (Advanced Encryption Standard) is widely used for all forms of data encryption. It operates on blocks of data (128 bits in size) and uses a secret key that can be 128, 192, or 256 bits long. The choice of key size provides a trade-off between security and performance. The process of AES uses complex mathematical operations, but the basic idea is that AES takes data, cuts it up, and scrambles it repeatedly so that it can't be unscrambled without the key. Using a puzzle as an analogy, AES operates as follows: 1. Start with a picture (Data): The original data you want to protect is your starting point. AES cuts this picture into small, equal-sized pieces (blocks of data). 2. Create the puzzle solution (Key Expansion): AES prepares the secret key. This key is like a secret puzzle solution guide. 3. Shake up the picture (Rounds): AES scrambles the pictures up to 14 times (rounds - depending on the key size). In each round, it substributes pieces (SubBytes), shuffles rows (ShiftRows), mixes up columns (MixColumns), and uses a piece of the secret key (AddRoundKey). 4. Finish the puzzle (Final Round): In the final round, AES leaves out the MixColumns step but still does the rest. This leaves us with an entirely new picture (the encrypted data) that looks nothing like the original. The only way to get back to the original picture (decrypt the data) is to reverse the entire process, and you can only do that if you have the secret key (the puzzle solution guide). 2. Asymmetric Encryption Asymmetric encryption, also known as public key encryption, uses two different but mathematically related keys for encryption and decryption: the public and private keys. The public key, as the name implies, is open to everyone, while the private key is kept secret. Any message encrypted with the public key can only be decrypted using the private key, and vice versa. This means that if Justin wants to send a secret message to Coltyn, he can encrypt the message using Coltyn's public key. When Coltyn receives the message, he can decrypt it using his private key. This mechanism provides a very high level of security and is the basis for many security protocols, including SSL and TLS. Asymmetric keys: Key management becomes easier with asymmetric keys because the public key can be openly shared without jeopardizing security. However, the private key must remain confidential. If a private key is exposed, all data encrypted with its corresponding public key becomes vulnerable. Popular asymmetric encryption algorithm - RSA: RSA (Rivest-Shamir-Adleman) is a widely used algorithm for asymmetric encryption and forms the basis of many secure communication protocols, including SSL and TLS. The security of RSA lies in the fact that, while the public key is known, deriving the private key from it would require factoring the modulus into its original prime numbers. This is a computationally difficult task, especially as the prime numbers used in practice are large. At a high level, RSA operates as follows: 1. Key generation: RSA begins with the selection of two large prime numbers. These numbers are used to generate the public and private keys. The public key consists of a modulus, which is the product of the two primes, and an exponent. The private key is also derived from these primes but is kept secret. 2. Encryption: If someone wants to send an encrypted message, they will use the recipient's public key to encrypt the plaintext. The resulting ciphertext can then be securely transmitted without fear of interception. 3. Decryption: Upon receiving the ciphertext, the recipient uses their private key to decrypt it back into the original plaintext. Encyption is a fascinating field that delves deep into mathematics, algorithms, and computer science. It is important to acknowledge that there is much more to learn beyond these basics, but I hope I have been able to outline the fundamentals in this article.