Purpose of Cryptography is to protect information from being read and understood by anyone except the intended recipient.
In practice encryption can be a function of time, the effort and time required for an unauthorized person is so large it is impractical. By the time it is decrypted it is of little value.
Block Cipher – Breaks the plaintext into blocks and encrypts each with the same algorithm
Cipher – Cryptographic transformation operates on the characters or bites
Ciphertext or Cryptogram – unintelligible message
Clustering – plaintext message generates identical ciphertext using the same algorithm but different keys
Codes – A cryptographic transformation that operates at the word or phrase level
Cryptanalysis – act of obtaining plaintext or key from ciphertext
Cryptographic Algorithm – Step-by-step procedure used to encipher plaintext and decipher ciphertext
Cryptography – Art and Science of hiding the meaning of communication
Cryptology – encompasses cryptography and cryptanalysis
Cryptosystem – set of transformations from message space to ciphertext space
Decipher - to undo cipherment process
Encipher – to make a message unintelligible to all except recipient
End-to-end encryption – Encrypted information that is sent from sender to receiver