奧頓多夫編碼
Ottendorf coding, also known as book cipher or dictionary code, is a cryptographic technique that uses a book or other text as the key for encoding and decoding messages. Here are a few examples to illustrate how Ottendorf coding works:
Using Page, Line, and Word Numbers: In this method, each word in the plaintext message is replaced with a set of numbers corresponding to the page number, line number, and word number within a chosen book. For example, the word "hello" might be encoded as "150-10-5" if it appears on page 150, line 10, and is the 5th word on that line in the chosen book.
Using Specific Words or Phrases: Instead of numerical coordinates, specific words or phrases from the chosen text can be used to encode the message. For instance, if the chosen book contains the sentence "The quick brown fox jumps over the lazy dog," the word "fox" might represent the letter "A," while "lazy" represents "B," and so on.
Using Letter Frequency: Another method involves assigning numbers to letters based on their frequency of occurrence in the chosen text. For example, the most common letter might be represented by "1," the second most common by "2," and so forth. Then, each letter in the plaintext message is replaced with its corresponding number.
Using a Combination of Methods: Ottendorf coding can also involve a combination of the above methods or additional variations tailored to the preferences of the code creator and recipient. For instance, a message might use page and line numbers for basic encoding, with specific words serving as additional modifiers or indicators for certain actions or meanings.
These examples demonstrate the flexibility and versatility of Ottendorf coding, allowing for creative and adaptable encryption and decryption techniques based on the chosen key text.
