4 ms·
Here's how it would work: You decide how many different friends and family you are going to send your secret message to, and how many of them will need to agre
by cjdavis 15y ago
Here's how it would work:
You decide how many different friends and family you are going to send your secret message to, and how many of them will need to agree to unlock the message together. Let's say you pick 15 recipients and 8 need to agree. Then ANY 8 of the 15 messages can be combined to decrypt the secret.
No 3rd party service needed at all.
Couldn't you encrypt the results again with different numbers? So you could do interesting things like 'my wife AND (any 3 of 50 others)'
- s2r2 15y ago'my wife AND (3 of 50)' You could take k=54 and give your wife 51 keys.
- Sniffnoy 15y agoWorks for this simple case, but I think iterating the procedure is more general. For instance, suppose there are 6 people -- A1, A2, A3, B1, B2, B3, and you want it to be recoverable given any 2 of the A group and any 2 of the B group; I'm pretty sure that can't be handled with a solution like the above.
- s2r2 15y agoI think your right. One (k,n)=(2,3) scheme for each group to unlock the (2,2)-scheme for the secret. And the wife just needs to remember one key this way...
- gwern 15y agoSimplest would just be to have the 3-of-50 decrypt to another encrypted file, and give the wife the passphrase to that. Nobody holds multiple keys, satisfies the 'AND', and is simple.