CrossCTF_2017: GovTech Web Challenge Level 1

Category: Web Points: 75 Description:

Here's a crypto warmup for you! Challenge here

Write-up

We are given a webpage with the strange encoded string BCBCBADABCABBABDBDCDBDBABCBBBCADBCCABBDDBAACBCABBDADBCBBADBABDDB.

Like the qualifiers, this is a play on base-4 letters and we can solve this by translating this to base-4 numbers.

BCBCBADABCABBABDBDCDBDBABCBBBCADBCCABBDDBAACBCABBDADBCBBADBABDDB
1212103012011013132313101211120312201133100212011303121103101331

Then, we can whip out the snake in us and use it's ability to convert bases fluently.

$ ./solve.py 
Flag: fLaG{tech_Base4}

Therefore, the flag is fLaG{tech_Base4}.