RN

Platform: spbctf | Category: Crypto | Type: Challenge | Difficulty: Medium | OS: NA | Author: XESXOR | Date: 2026-03-08 | Status: Solved Techniques: Convert large numbers to 2-byte ASCII pairs, Roman numeral decoding with vinculum (overline = ×1000)

Summary

Task: Decode Roman numerals with vinculum (overline = ×1000) from HTML with CSS styling. Solution: Parse overlined and normal parts, convert to decimal, split each number into 2 bytes to get ASCII characters.

RN — cryptokids20

Description

Roman numerals with vinculum (overline via CSS). Each number = 2 ASCII chars (high byte, low byte).

Solution

Parse overlined (×1000) and normal parts. Convert to decimal. Split each number into 2 bytes → ASCII. ‍​‌‌​​‌​​​‌‌​​‌​​​​‌‌​‌​​​​‌‌‌​​‌​​‌‌​​​‌​​‌‌‌​​​​​‌‌​‌‌​​​‌‌​​​​‍