But you can't revoke his ability to keep bruteforcing the message. - Sent from my tablet Den 19 sep 2012 23:01 skrev "mhey...@gmail.com" <mhey...@gmail.com>:
> Doh, don't know why I brought public-key crypto into this. There isn't > a need for it. Just pick, say, an AES key and give the trustee some of > the key's bits so they only have to brute force part of the key. > > On Wed, Sep 19, 2012 at 4:48 PM, mhey...@gmail.com <mhey...@gmail.com> > wrote: > > On Wed, Sep 5, 2012 at 9:51 AM, StealthMonger > > <stealthmon...@nym.mixmin.net> wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- > >> > >> Can there be a cryptographic "dead man switch"? A secret is to be > >> revealed only if/when signed messages stop appearing. It is to be > >> cryptographically strong and not rely on a trusted other party. > >> > > Every three months I, the Grantor, encrypt my secret in a new > > secret-encrypting-key and place that secret in my box. (I keep my box > > away from others - maybe put it in a safe). > > > > I also encrypt that secret-encrypting key in a public key but not too > > strong a public key, one that can be broken in three months time. > > > > I then throw away the private key to that public key (I don't need it, > > I know my secret). > > > > I give the public-key encrypted secret-encrypting key to the trustee, > > heck I can publish it on the web if I want. > > > > If I should die, I will stop re-encrypting the secret and the trustee > > (that I never really trusted) can break the public key and get to the > > secret. > > > > I know a second scheme that we worked out years ago when one of our > > group was working on DTN (delay tolerant networking) where we would > > encrypt something and bounce the encrypting key off a distant node and > > get a few seconds or minutes of safe time until the something could > > get decrypted. This scheme has the benefit of not failing if some > > whiz-bang new crypto breaking system comes along but deals with much > > shorter time periods. I assume that if I'm using the crypto-only > > method, then I will keep apprised of whiz-bang new crypto breaking > > systems and re-encrypt early with a larger key to get back on my three > > month schedule if such a faster breaking system should appear. > > ---- > > Michael Heyman > _______________________________________________ > cryptography mailing list > cryptography@randombit.net > http://lists.randombit.net/mailman/listinfo/cryptography >
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