RTLxHA CTF 21 Write-Up

  1. Basic
Web-Basic-10pt
admin' OR 1=1-- -
  1. Welcome.
Crypto-Welcome-5pt
echo -ne "UlRMe0g0VkVfRlVOX1BMNFkxTkchfQ==" | base64 -d
>>> A^B=C #Plain number di encode menjadi C
>>> C^B=A #Mencari Key dengan meng-XOR encoded number dan plain number hasil tersebut akan menghasilkan Key
>>> A^C=B #Mencari plain number dengan meng-XOR encoded number dan Key
key="ABCD"
plainText="test"
XOR:
key[n]^plainText[n] # "A"^"t", "B"^"e"...
# Contoh 1
a="make it simple"
b="test"
# Contoh 2
a="abcd"
b="plain"
a="abcd"
b="plaintext"
b[n]^a[n]"p"^"a"=int(17)
"l"^"b"=int(14)
"a"^"c"=int(2)
"i"^"d"=int(13)
--------- string a sudah habis dan kembali dari index 0
"n"^"a"=int(15)
"t"^"b"=int(22)
"e"^"c"=int(6)
"x"^"d"=int(28)
--------- string a habis lagi dan kembali lagi dari index 0
"t"^"a"=int(21)
  1. Bad Developers

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PARSECT // IT Security Enthusiast // STOICISM // KEEP DO SOMETHING LEGAL

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