Write Up Online CTF FIT Competition UKSW 2016 Tahap Pertama - Cryptography [Lols~]

Write Up Online CTF FIT Competition UKSW 2016 Tahap Pertama Cryptography Lols~

Soal : https://www.dropbox.com/s/ddsstpyysjmr8qw/Crypto2.txt?dl=0 Format Flag : FIT2016{[A-z]}

Flag : FIT2016{antonlim_64nt3ng}

Referensi Tools : http://www.onlinebarcodereader.com/
PoC (Proof of Concept):

1. Peserta diberikan soal crypto berupa gambar yang di encode ke base64, cukup gunakan Google Chrome browser untuk mendecode soal ini. Copy dan Pastekan code dibawah ke dalam browser.

data:image/png;base64,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

2. Dari hasil decode di atas pada google chrome, didapatkan sebuah gambar hasil dari decoding base64 di atas, dapat dilihat pada gambar dibawah ini.