Ethereum is not cryptographically secure, since it does not have a deterministic state (the DAO "rescue fork"), so its use as a ledger that can be back-traceable may be limited (next generation systems can include emulators for older systems, the amount of proof-of-work on Ethereum is a good metric for how long that state existed, but it is not easy to emulate arbitrary decisions to alter the state, like with the DAO fork), so to store patents or proof-of-existence there may not be future proof.

Indexing using private key - public key mappings

I indexed my idea for 6-tubulin memory bytes within the addresses that the private keys microtubule and spiraeum map to, as one way to remember where I put the proof-of-existence. That way, since Ethereum uses secp256k1, the public key is easily derived from the private key, and the address is keccak256(publicKey), it ought to be easy to remember where it was indexed.

The private key microtubule, hex 6d6963726f747562756c65 and 42 zeros,

6d6963726f747562756c65000000000000000000000000000000000000000000

maps to the address 0x7126CDF91B08c1382F0C28d0EF1E6D7dF05f1D04

and the first transaction there has a data field with the idea for 6-tubulin memory bytes

The private key spiraeum, hex 737069726165756d and 48 zeros,

737069726165756d000000000000000000000000000000000000000000000000

maps to the address 0xe3Bc6BF9332a3f2B53ac2C241a6172724e43cc61

and the first transaction there has a data field with the idea for 6-tubulin memory bytes