Enigma machine — Military Enigma machine … Wikipedia
One-time pad — Excerpt from a one time pad In cryptography, the one time pad (OTP) is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit … Wikipedia
Substitution cipher — In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters,… … Wikipedia
Transposition cipher — In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext (which are commonly characters or groups of characters) are shifted according to a regular system, so that the ciphertext… … Wikipedia
ROT13 — replaces each letter by its partner 13 characters further along the alphabet. For example, HELLO becomes URYYB (or, rev … Wikipedia
Caesar cipher — The action of a Caesar cipher is to replace each plaintext letter with one fixed number of places down the alphabet. This example is with a shift of three, so that a B in the p … Wikipedia
Cryptogram — For other uses, see Cryptogram (disambiguation). Not to be confused with cryptogam, the plants which reproduce by using spores. Example cryptogram. A cryptogram is a type of puzzle which consists of a short piece of encrypted text. Generally the… … Wikipedia
Index of coincidence — In cryptography, coincidence counting is the technique (invented by William F. Friedman[1]) of putting two texts side by side and counting the number of times that identical letters appear in the same position in both texts. This count, either as … Wikipedia
Book cipher — A book cipher is a cipher in which the key is some aspect of a book or other piece of text; books being common and widely available in modern times, users of book ciphers take the position that the details of the key is sufficiently well hidden… … Wikipedia
Cryptex — Replica cryptex: prize from Google Da Vinci Code Quest Contest The word cryptex is a neologism coined by the author Dan Brown for his 2003 novel The Da Vinci Code, denoting a portable vault used to hide secret messages. It is a combi … Wikipedia
