First, if it uses PRNG with a fixed-size state, it isn't accurate to say it never repeats, correct? It will be periodic eventually, even if that takes 2^256 operations or more.
Second, can you go more into the potential practical or theoretical advantages? Your scheme is certainly more complicated, but I don't see how it offers better tamper protection or secrecy than a block cipher operating in an authenticated mode (AES+GCM, for instance). Those have a number of practical advantages, like parallel encryption/decryption and ubiquitous hardware support.
You are correct. The probability of a state collision is cryptographically negligible, on the order of breaking a 256-bit hash function.
You're also right that AES-GCM is faster and has hardware support. Ariadne explores a different trade-off. Its primary advantage is its architectural agility.
Instead of a fixed algorithm, the sequence of operations in Ariadne is dynamic and secret, derived from the key and data history. An attacker doesn't just need to break a key; they have to contend with an unknown, ephemeral algorithm.
This same flexible structure allows the core CVM to be reconfigured into other primitives. We've built concepts for programmable proofs-of-work, verifiable delay functions, and even ring signatures.
FYI your comments seem to be showing up as dead (dead comments don't show up by default, only when people logged into HN have them enabled), I think something may have triggered a shadowban on your account. Might want to send a message to the moderators.
First, if it uses PRNG with a fixed-size state, it isn't accurate to say it never repeats, correct? It will be periodic eventually, even if that takes 2^256 operations or more.
Second, can you go more into the potential practical or theoretical advantages? Your scheme is certainly more complicated, but I don't see how it offers better tamper protection or secrecy than a block cipher operating in an authenticated mode (AES+GCM, for instance). Those have a number of practical advantages, like parallel encryption/decryption and ubiquitous hardware support.