mde5

mde5

Challenge Description

Is something broken? Probably.

Short Writeup

• The Hash algorithm uses DES encryption, and the data is fed as the key.
• Since DES has parity bits for the key that are disregarded, its possible to cause a collision
• This lets us get a reused nonce on two ECDSA signatures.
• We calculate the private key, and sign the message.

Flag

icc{https://www.youtube.com/watch?v=xFnc00wpAPg}

Author

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