Encryption

Encryption

1. Encryption- is when the plaintext is converted into the ciphertext

2. Plaintext- is the unencrypted message

3. Ciphertext

   • Caesar Cipher
     • Keyword- Is where a word is chosen to be the keyword and then when encrypting and decryptin it is placed at the beginning of the alphabet and has any duplicated letters taken out, the entire alphabet is then wrote out in order excluding any letters in the keyword.
     • Shift- This is were the entire alphabet is shifted along by a certain amount of spaces. For example if the shift was 3 then A would become D and so on.
   • Railfence- Is where the plain text is written in a pattern containing a certain amount of rows and columns and then is encrypted by reading the letters in each row
   • Ployalphabetic Cipher- any text that uses a substitution cipher
     • Substitution Cipher- This is where certain letters phrase or common terms are replaced with another letter or number from ciphertext.
   • Vernam Cipher- a cipher where 1 time key is used. It is a secure cipher because the key is only used once.
   • Transposition Cipher- Positions of plain text are shifted according to a regular system.
   • Route Cipher- Route cipher is similar to railfence as it writes the plaintext in a pattern vertically downwards and then encrypts the message by reading horizontally
   • One time pad- a single use key often used with the vernam cipher.

4. Decryption- is when the ciphertext is being converted into plaintext.

5. Frequency Analyses- is where the decrypter finds the frequency of the encrypted letters in the message to try and find which ones could be commonly used letters such as the vowels