Imagine what you would do if you discovered how to factor efficiently? Think carefully. You now how the power to decrypt much of the world's banking and internet traffic and spoof certificates. There are forces in this world that would kill you to have this power. Would you publish your findings for everlasting fame? Would you sell it to the NSA for money (remember you can prove your power without releasing your algo…
For both factoring or preimaging, I'd think I'd offer it publicly (any three lettered agency will find you anyway). I mean offering the 'service' as a commercial, legal, tax paying business.
- Offer factoring/preimages as a service, start with very high prices (like a million USD per input).
- Lower the price after every x sales. Like for every 100 sales, reduce the price by 50%
- Once the price goes below a certain threshold, release the algorithm.
This method has (I think) the most benefits:
- it slowly released to the public, giving everybody enough time to migrate away
- it makes you less of a target for government/organised crime, as it's less controversial for them just to pay instead of trying to extort.
- by incorporating a business and paying tax, offering this service will probably be legal in most countries (not sure though)
- by the time you release the algo, you'll have made plenty of money to retire, and you'll no longer be at risk since it is now public information.
And for those wondering: if you find practical SHA-2 preimage, you would NOT be able to mine bitcoin with it.