In cryptography, a cipher (or cypher) is a method for protecting data through encryption and decryption. Most ciphers require a specific key for encryption and decryption, but some ciphers like the ROT13 or Atbash ciphers have fixed keys. Many of the ciphers listed here were for military or other significant use during an earlier time, but today mostly are used only by puzzle makers.
Text and Word Tools
Wordplay and witty texts is one of the oldest forms of puzzles. Anagrams have been traced to the time of the Ancient Greeks, and they still are popular in modern brain teasers. Synonyms are common not only in crosswords, but plays a role in a wider range of puzzles. This section also contains text processing tools, which are useful for reversing, changing case, etc of texts.
These tools will help you identify the types of encodings and ciphers used.
Modern encryption methods can be divided by the key type and their operation on input data. Symmetric key algorithms use the same key for encryption and decryption (private key cryptography). Asymmetric key algorithms use different keys for encryption and decryption (public key cryptography). With symmetric keys, the sender and receiver must have agreed upon a key in advance, while with asymmetric keys anyone can send messages to the receiver. Also depending on their operation, ciphers are either block ciphers (encrypting a fixed block size) or stream ciphers (encrypting a continuous stream of data).
While encryption protects information from being understood, an even higher protection would be if the information is hidden. The word steganography comes from the Greek word "steganos", meaning concealed, and "graphein", meaning writing. Modern steganography can hide information in images and audio files. Also information can be manually hidden in images through the use of very low contrast colors or metadata.
Computers and digital devices need to represent letters in appropriate ways. ASCII codes are very common for storing texts, but with the demand to support more non-English texts, the popularity of Unicode is increasing. Hashes are not encodings, but since they are more or less unique for all words, they can be considered like encodings (although much more difficult to reverse).
Mathematics play an important role in logic puzzles and code-breaking. It is important to be able to convert between different number systems, and detect special properties of numbers such as that they are prime numbers. Also number sequences, like the Fibonacci sequence, are commonly used in puzzles.
Every alphabet has a number of symbols that are the building blocks of the specific language. In addition to traditional written languages, alphabets have evolved for telegraphy (Morse code), visually impaired people (Braille) and maritime signal flags. Further alphabets have evolved in popular culture, such as the Klingon alphabet (from Star Trek) or dancing men code (from Sherlock Holmes).
Are you ready to take the "red pill" and go even further down the "rabbit hole"? Then this section is for you.
You can't rely on tools only
Although tools can be helpful, there's a saying: "A fool with a tool is still only a fool". Good quality code-breaking puzzles can't be solved simply by using tools. It's your wits and creativity that matter, and the tools are just there to help explore your ideas.