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2026-05-10
Crypto
Hard
Raptor Weekly 2 - ECHELON Crypto 3 - 5.1 ; ECHELON
Assembling three named artifacts recovered across five prior challenges, a signing key exfiltrated in four fragments, a C2 handshake key, and a certificate-derived access key. Then computing their HMAC-SHA256 combination to authenticate to the CODEWORD tier.
crypto
hmac
multi-stage
ECHELON
2026-03-01
Crypto
Insane
DEADROP Crypto 6 - CIPHER7
Fourstage cryptographic chain, repair a corrupted Reed-Solomon encoded key file, solve the discrete logarithm problem on a backdoored elliptic curve with smooth group order via Pohlig-Hellman, locate a hidden nonce in a binary header, derive the AES key, and decrypt the final briefing.
reed-solomon
elliptic-curve
pohlig-hellman
ecdlp