In cryptography, ciphertext is the result of encryption performed on plaintext using an algorithm, called a cipher.
Cryptography began thousands of years ago.Early 20th century, the invention of complex mechanical and electromechanical machines.
Throughout history, the need for secrecyhas been important.Abu Yusuf Ya’qub ibn e Ishaaq Al-Kindi wasthe first to De-Cipher an encryptedmessage.
Historical pen and paper ciphers used in the past are sometimes known as classical ciphers. They include:Substitution cipher: the units of plaintext are replaced with ciphertext (Caesar cipher)Transposition cipher: the ciphertext is a permutation of the plaintext (Rail fence cipher)Polyalphabetic substitution cipher: a substitution cipher using multiple substitution alphabets (Vigenère cipher and Enigma machine)Permutation cipher: a transposition cipher in which the key is a permutationPrivate-key cryptography (symmetric key algorithm): the same key is used for encryption and decryptionPublic-key cryptography (asymmetric key algorithm): two different keys are used for encryption and decryption