Types of Cryptography: Symmetric, Asymmetric, and Hash Functions
Cryptographic systems can be broadly classified into three categories: symmetric encryption, asymmetric encryption, and hash functions.
Symmetric Cryptography: In symmetric cryptography, the same key is used for both encryption and decryption. This method is fast and efficient but has the challenge of securely sharing the key between parties before communication. If the key is intercepted, the entire system is compromised.
Example: The Advanced Encryption Standard (AES) is a widely used symmetric encryption algorithm.
Asymmetric Cryptography: Asymmetric cryptography, also known as public-key cryptography, uses a pair of keys: a public key (known to everyone) and a private key (kept secret). Data encrypted with the public key can only be decrypted by the corresponding private key, and vice versa. This system eliminates the need for secure key distribution and is the foundation of secure communications over the internet.
Example: RSA (Rivest–Shamir–Adleman) is one of the most popular asymmetric encryption algorithms.
Hash Functions: A hash function takes an input (or message) and produces a fixed-length output, typically called a hash or digest. Hash functions are used primarily for data integrity checks, ensuring that data has not been altered during transmission. They are one-way functions, meaning you cannot reverse the process to obtain the original message.
Example: SHA-256 (part of the SHA-2 family) is a commonly used cryptographic hash function.