Text processing tools
Text processing tools are useful for cleaning up and manipulating text, such as reversing, changing case, remove unwanted whitespaces, or counting the number of letters, lines and sentences. They can save a lot of manual effort when preparing a text for further analysis or decryption.
Anagrams have been popular in culture since the time of the Ancient Greeks. Several pseudonyms are in fact anagrams, as well as music titles and other witty names. Cryptic crossword puzzles frequently used anagrams, as well as many other kinds of code-breaking games. Anagram generators can be helpful to find all possible anagrams of a text.
Synonyms and antonyms
Clues to code-breaking puzzles are frequently expressed as synonyms or related words. Also antonyms (words with opposite meanings) are sometimes used. With a thesaurus, you will find a list of all synonyms for a given word.
Cryptic crosswords is a special kind of crossword puzzles which are especially popular in the United Kingdom. Basically you have to "read them the right way" to find the solution. Usually what they seem to say when read normally is only a distraction. A well-designed cryptic crossword has a logic path to finding the solution through the cryptic clues.