Re:Show HN: Ariadne – a Rust implementation of aperiodic cry...
by ciphernomad-org on Monday June 23, 2025 @05:07AM
(#44353758)
The security does not depend on the path's structure. It depends on the CVM's state ratchet.
The key and IV for every single round are derived from a keyed hash of the CVM's current state. This state is a cryptographic digest of the entire operational history up to that point.
So, even if a path structurally resembled a weak cipher like 2DES, the rounds would not have related keys. Each step is effectively a fresh cipher instance with a unique, unpredictable key. A meet-in-the-middle attack is not possible because there is no "middle" with a key relationship to exploit.
The key and IV for every single round are derived from a keyed hash of the CVM's current state. This state is a cryptographic digest of the entire operational history up to that point.
So, even if a path structurally resembled a weak cipher like 2DES, the rounds would not have related keys. Each step is effectively a fresh cipher instance with a unique, unpredictable key. A meet-in-the-middle attack is not possible because there is no "middle" with a key relationship to exploit.