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DEADROP Crypto 4 - DSA Again?

Two DSA signatures from the same key share an identical r value, a dead giveaway of nonce reuse. Recover the private key, forge a signature over the target authorization message, and submit it to the server.

WHAMazon! Crypto 5 - Signature Residue

Exploiting a weak (low) DSA nonce k to brute-force the signing secret, recover the private key x, and derive the flag via SHA-256.