Substitution Challenges
Because this challenges are all very similar, we will not describe them in own articles 🙂 .
Solving
Substitutions cypher replace the 26 letters of an alphabet with other letters (one letter matches only one other). If you can find out which letter was replaced with which letter, then you can crack this cypher relatively easily.
The best method for this, is the Frequency Analysis or Frequency Attack. In cryptography, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking substitution ciphers (e.g. mono-alphabetic substitution cipher, Caesar shift cipher, Vatsyayana cipher). Frequency analysis consists of counting the occurrence of each letter in a text. Frequency analysis is based on the fact that, in any given piece of text, certain letters and combinations of letters occur with varying frequencies. For instance, given a section of English language, letters E, T, A and O are the most common, while letters Z, Q and X are not as frequently used.
To solve the three substitution challenges we used a frequency attack.. with this online tool.
Please look at the subheadings to see the letter assignments for each challenge.
substitution0
Description
A message has come in but it seems to be all scrambled. Luckily it seems to have the key at the beginning. Can you crack this substitution cipher?
Download the message here.
Solving
IADNMLPFYEJSWBZVXUHKGROCQT
ABCDEFGHIJKLMNOPQRSTUVWXYZsubstitution1
Description
A second message has come in the mail, and it seems almost identical to the first one. Maybe the same thing will work again.
Download the message here.
Solving
ABCDEFGHIJKLMNOPQRSTUVWXYZ
*YE*FUC*GR*I*KNPTOQ*L**HSAsubstitution2
Description
It seems that another encrypted message has been intercepted. The encryptor seems to have learned their lesson though and now there isn't any punctuation! Can you still crack the cipher?
Download the message here.
Solving
ABCDEFGHIJKLMNOPQRSTUVWXYZ
R*UH**YNETLGIOFVM*PS**BC*D