Inventor

Platform: spbctf | Category: Crypto | Type: Challenge | Difficulty: Medium | OS: NA | Author: XESXOR | Date: 2026-03-08 | Status: Solved Techniques: Big integer to bytes conversion, Custom base-N decoding with emoji alphabet

Summary

Task: Decode custom base29 encoding with emoji alphabet. Solution: Map emojis to positions, convert base-29 number to bytes to reveal the flag.

Inventor — cryptokids20

Description

Custom base29 with emoji alphabet. Map emojis to positions, treat as base-29 number, convert to bytes.

Solution

Parse emoji sequence → base29 digits → big integer → bytes. Decoded Russian text describes flag as 'REDACTED' ‍​‌‌​​‌​​​‌‌​​‌​​​​‌‌​‌​​​​‌‌‌​​‌​​‌‌​​​‌​​‌‌‌​​​​​‌‌​‌‌​​​‌‌​​​​‍