ensar@seker:~$ensar seker / security · research · life
spotlight / keynote
A lifelong goal, realised. Keynote speaker at TEDxGuatemalaCity, under the theme Decoded Leadership, on why understanding how attackers think is the starting point for every good defence.
More talks on /speaking ↗01 / traceroute ensar.seker
Security, research, compliance, data protection and business continuity for an extended threat intelligence company. Professional ransomware negotiator.
Cyber-risk quantification for boards and security teams.
Led a practice that completed 495 pentest and red-team projects in 7 months.
Blue-team lead across 42 SOC projects.
Head of EU projects; led the Cyber Training Unit; trained armed forces of 4 nations with NATO SPS funding.
Locked Shields and Crossed Swords exercises, CyCon reviewer, critical-infrastructure research.
IT operations, policy and budget for the national oil company.
Secure inter-branch networking and an internal cloud intranet.
Leading AI transformation ethically, effectively and at scale.
Doctorate completed in 2024.
Graduate studies in New York.
The engineering foundation.
02 / interactive
Explore the site from a real (well, friendly) shell. Type help, or tap a command below. Press ⌘K or / anywhere to jump to a page.
ctf / capture the flag
0/4 solved
Four locked messages, from a cipher Caesar used to a byte-level XOR. Decrypt each one, type the last word you find, and unlock the next. No tools needed, just curiosity.
ciphertext
WKH SDVVZRUG LV FXULRVLWB
WKH SDVVZRUG LV FXULRVLWB
Julius Caesar moved every letter the same number of places. Slide the wheel until the words make sense.
✓ A Caesar cipher has only 25 possible keys, so an attacker can try them all in seconds. That is a brute-force attack.
ciphertext
bmV4dCBrZXk6IHNoaWVsZHM=
Letters, digits, + and /, and an = at the end. This is a famous encoding, not a cipher: anyone can reverse it without a key.
✓ Base64 hides nothing. Never treat encoded data as protected data.
ciphertext
GHX OASPSE IL HNLEWAN
GHX OASPSE IL HNLEWAN
The key is a four-letter alliance headquartered in Brussels. Type it in the key box.
✓ A repeating key beats simple frequency analysis, but a short key still leaks patterns. Long, random keys matter.
ciphertext
5e 42 4f 0a 4c 43 44 4b 46 0a 5d 45 58 4e 0a 43 59 0a 58 4b 4e 4b 58
…
Each byte was XORed with a single key byte. The 0a bytes appear wherever there is a space, and a space is 0x20. What is 0x20 ⊕ 0x0a?
✓ Single-byte XOR falls to a known-plaintext guess. Real ciphers like AES never reuse a key this way.
access granted
You think like a defender and an attacker. That's the whole job. Tell me you solved it ↗
for young defenders
Password monsters, phishing spotting, a secret decoder ring and more, for ages 7–12.
03 / modules loaded
in conversationKeynotes, TEDx and conference stages. AI Security Roadshow · Istanbul.
going deeperResearch, publications and practical projects, from smart grids to exascale platforms.
out in the worldProfessional visits, Japan and conversations across borders.
04 / tail -f notebook.log
05 / ls -la ~/archive
good conversations start somewhere