I also want to know, if I'm still around, when and if those documents are decrypted. I.e. In the event that my friend isn't as trustworthy as I presume, I want to find out if s/he decrypts the files while I'm still around.
There is a solution, a simple one, that can split the repsonsibility. Encrypt the documents with a normal symmetric cryptosystem, something strong and unlikely to be compromised in the near future, say LOKI or IDEA, or maybe 3DES if you trust it. XOR the key with a random value, give the result to your friend and print out the random value, sign it and give it to a bank or solicitor as a bequest in your will to your friend. If and when something does happen the friend proves your death to the bank using probate or a death certificate, gets the random value, XORs it with the string you gave her and she has the key. She can then easily decrypt the data. Yes, it does involve a third party, but it is unlikely your friend could collude with a respected bank or solicitor/notary to recover the key... Really all depends how paranoid you are. Datacomms Technologies data security Paul Bradley, Paul@fatmans.demon.co.uk Paul@crypto.uk.eu.org, Paul@cryptography.uk.eu.org Http://www.cryptography.home.ml.org/ Email for PGP public key, ID: FC76DA85 "Don`t forget to mount a scratch monkey"