Frequency Analysis
If I have you solving challenges with automatic tools, I want you to know how they work at least!
Read this: https://www.dcode.fr/frequency-analysis
Use the https://gchq.github.io/CyberChef/ Frequency Distribution Tool to determine the frequency of characters, bigrams, and trigrams of the text:
"Frequency analysis is the study of the distribution of the letters in a text. Analysis of frequencies help decrypting substitution-based ciphers using the fact that some letters apparitions are varying in a given language : in english, letters E, T or A are common while Z or Q are rare."
Then use the tool to determine frequency of chars, bigrams, and trigrams of this text:
"Iuhtxhqfb dqdobvlv lv wkh vwxgb ri wkh glvwulexwlrq ri wkh ohwwhuv lq d whaw. Dqdobvlv ri iuhtxhqflhv khos ghfubswlqj vxevwlwxwlrq-edvhg flskhuv xvlqj wkh idfw wkdw vrph ohwwhuv dssdulwlrqv duh ydublqj lq d jlyhq odqjxdjh : lq hqjolvk, ohwwhuv H, W ru D duh frpprq zkloh C ru T duh uduh."
Read the explanation at the bottom of this: https://www.dcode.fr/monoalphabetic-substitution
Then decrypt this: "Iuhtxhqfb dqdobvlv lv wkh vwxgb ri wkh glvwulexwlrq ri wkh ohwwhuv lq d whaw. Dqdobvlv ri iuhtxhqflhv khos ghfubswlqj vxevwlwxwlrq-edvhg flskhuv xvlqj wkh idfw wkdw vrph ohwwhuv dssdulwlrqv duh ydublqj lq d jlyhq odqjxdjh : lq hqjolvk, ohwwhuv H, W ru D duh frpprq zkloh C ru T duh uduh."
Most automated cryptography tools use this sort of technique behind the scenes.
Crypto has a lot of math, but luckily, because it is math, someone else has usually written a tool to do it for you. It takes a looooot of work to get to the cutting edge in this field.
- What is text fitness?
- Explain how frequency analysis can be used to automatically detect the correct decryption of a ciphertext.
- What is leet speak?
- How would this break a text fitness calculation?