I am making a prediction. For reasons discussed in this previous post, its important that I announce the prediction but keep it a secret until the uncertainty is resolved. Following the suggestion of a commenter, I wrote my prediction in a text file and ran it through the SHA1 secure hash algorithm (using the web tool here.) Here is the hash:
Briefly, this is a digital signature that is (for practical purposes) uniquely associated with the text. But the algorithm is “one-way:” unless you have a powerful computer you will not be able to invert the mapping and discover my prediction from the hash.
When the uncertainty is resolved (it will happen in the not-too-distant future) I will post the prediction here. You can then take it and generate the SHA1 hash and verify that it is the one above. That will prove that the prediction I show you is in fact the one that I have made today.
While we are waiting to find out, you can try to predict what my prediction is. (No, my prediction is not about what you will predict I predicted.)
Update on Jan 10 (one day later:) Having forgotten one important detail, I have updated the prediction and the new hash is:
When I reveal the prediction, sometime before the Summer Solstice, I will reveal both text files and you will see the (innocuous) reason for the update.
As suggested in the comments, since I am able to modify the text of this blogpost, I should post the hash somewhere that it cannot be modified. Since Twitter puts a timestamp on every tweet and tweets cannot be edited ex post, I tweeted the two hashes. Here and here.