https://x3ric.com/blog/tags/ecc/CTF notes, systems work, and writeups.Hugoen-usSat, 06 Jun 2026 21:41:13 +0200https://x3ric.com/blog/posts/HackTheBox-400Curves-Challenge/https://x3ric.com/blog/posts/HackTheBox-400Curves-Challenge/Mon, 05 May 2025 09:20:00 +0800challengehtbcryptorsalatticeecc400Curves: turn the RSA leak into a lattice recovery, rebuild the secret values, and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-secure-source-Challenge/https://x3ric.com/blog/posts/HackTheBox-secure-source-Challenge/Sun, 16 Feb 2025 00:20:00 +0800challengehtbcryptoprnglatticeecchashsecure source: reconstruct the PRNG state from the leak, replay it, and recover the flag.https://x3ric.com/blog/posts/HackTheBox-Digital-Safety-Annex-Challenge/https://x3ric.com/blog/posts/HackTheBox-Digital-Safety-Annex-Challenge/Tue, 04 Feb 2025 00:20:00 +0800challengehtbcryptoecchashDigital-Safety-Annex: use the curve leak or invalid-curve path to recover the secret and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-Arranged-Challenge/https://x3ric.com/blog/posts/HackTheBox-Arranged-Challenge/Wed, 22 Jan 2025 09:20:00 +0800challengehtbcryptoaeslatticeecchashArranged: abuse the AES misuse, derive the missing key material, and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-ElElGamal-Challenge/https://x3ric.com/blog/posts/HackTheBox-ElElGamal-Challenge/Wed, 22 Jan 2025 09:20:00 +0800challengehtbcryptoeccElElGamal: use the curve leak or invalid-curve path to recover the secret and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-Fast-Carmichael-Challenge/https://x3ric.com/blog/posts/HackTheBox-Fast-Carmichael-Challenge/Wed, 22 Jan 2025 09:20:00 +0800challengehtbcryptoeccFast Carmichael: use the curve leak or invalid-curve path to recover the secret and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-Iced-Tea-Challenge/https://x3ric.com/blog/posts/HackTheBox-Iced-Tea-Challenge/Wed, 22 Jan 2025 09:20:00 +0800challengehtbcryptoaeseccIced Tea: abuse the AES misuse, derive the missing key material, and decrypt the flag.https://x3ric.com/blog/posts/HackTheBox-Birds-of-randomness-Challenge/https://x3ric.com/blog/posts/HackTheBox-Birds-of-randomness-Challenge/Fri, 13 Dec 2024 09:20:00 +0800challengehtbcryptorsaprnglatticeeccEnter the challenge flag to unlock this writeup.https://x3ric.com/blog/posts/HackTheBox-LostKey-Challenge/https://x3ric.com/blog/posts/HackTheBox-LostKey-Challenge/Fri, 13 Dec 2024 09:20:00 +0800challengehtbcryptorsaaeslatticeecchashEnter the challenge flag to unlock this writeup.https://x3ric.com/blog/posts/HackTheBox-The-Last-Dance-Challenge/https://x3ric.com/blog/posts/HackTheBox-The-Last-Dance-Challenge/Fri, 13 Dec 2024 09:20:00 +0800challengehtbcryptoxoreccEnter the challenge flag to unlock this writeup.https://x3ric.com/blog/posts/HackTheBox-JerryTok-Challenge/https://x3ric.com/blog/posts/HackTheBox-JerryTok-Challenge/Thu, 12 Dec 2024 09:20:00 +0800challengehtbcryptoeccEnter the challenge flag to unlock this writeup.https://x3ric.com/blog/posts/HackTheBox-Perfect-Synchronization-Challenge/https://x3ric.com/blog/posts/HackTheBox-Perfect-Synchronization-Challenge/Wed, 11 Dec 2024 09:20:00 +0800challengehtbcryptoaeseccvigenerePerfect Synchronization: recover the Vigenere key from the ciphertext, decrypt the message, and verify the flag.