Digital security 01 of many: Cipher… Basic encryption

This series “Digital security” is from my notes prepared for certifications.

A cipher is any message that follows a pattern based on which it can be converted back to the original intelligible message.

Substitution cipher is one such algorithm of creating ciphers.

ABCDE….YZ can be substituted with letters of the same index position after circular-rotating the standard English alphabet to the left by two letters: CDEFG….AB.

Name = Pcog

and so on.

Ciphers are the earliest form of encryption.

The substitution cipher shown above, is trivial and can be easily ‘De-ciphered’ by trial and error or with a good eye for recurring patterns in language.

Any message that isn’t encrypted is called Cleartext.

Any input to encryption is called Plaintext.

Any output of encryption is called Ciphertext.

                  Cipher Key
Plaintext   ====================>  Ciphertext

Binary representation of the plaintext, allows for binary operations on which are hard even for computers to crack without knowing the cipher key.