What Is a Cipher?
A cipher is a type of encryption technique used to protect data from unauthorized access. It involves the use of an algorithm, or mathematical formula, to scramble plain text into an unreadable form known as ciphertext. The process of deciphering this encrypted information back into its original form is called decryption. Ciphers are commonly used in computer networks and other communication systems for secure transmission of sensitive information such as passwords and credit card numbers.
Cipher algorithms can be divided into two main categories: symmetric-key ciphers and public-key ciphers. Symmetric-key ciphers involve using one key (or secret) that both the sender and receiver must know in order to encrypt and decrypt messages; examples include AES, DES, RC4, etc. Public-key ciphers require two different keys – one for encryption (public key) and another for decryption (private key). Examples include RSA, Diffie–Hellman Key Exchange Protocols, ElGamal Encryption Scheme etc. Both types have their own advantages and disadvantages depending on the application they are being used for; however they all provide strong security against malicious attacks if implemented correctly with proper protocols in place.