Challenge Points: 100
Challenge Description:
“The fault, dear Brutus, is not in our stars, but in ourselves.”
(I.ii.141) Julius Caesar in William Shakespeare’s Julius CaesarCiphertext: 7sj-ighm-742q3w4t
Since every flag in the CTF had to start with “RC3-2016”, we know partial plaintext value.
This led me to find a relation between the letters and the digits using the first 7 characters of the ciphertext and “RC3-2016”. The pattern that I could figure out was this:
| plaintext | ciphertext |
|---|---|
| W | C |
| X | D |
| Y | E |
| Z | F |
| 0 | G |
| 1 | H |
| 2 | I |
| 3 | J |
| 4 | K |
| 5 | L |
| 6 | M |
| 7 | N |
Ciphertext: 7sj-ighm-742q3w4t
Using lookup table to substitute ciphertext character with its corresponding plaintext character, we get:
Flag: RC3-2016-ROMANGOD
Pretty basic :)
Looking forward to exploring and solving more questions in Cryptography!