Re: Any of a set of keys for encryption

From: Douglas A. Gwyn (DAGwyn_at_null.net)
Date: 11/11/05 

Date: Thu, 10 Nov 2005 23:06:38 GMT

glenlow@pixelglow.com wrote:
> Is there any cipher or cryptosystem that allows any of a limited set of
> keys to decrypt a message?

Yes, just encrypt with each of the keys and concatenate
or interleave the resulting ciphertexts. Obviously any
of the keys can decrypt the corresponding piece of the
result. If you don't want to externally index the keys
then you can include a checksum in the plaintext and the
decryptor can try the key at each position until the
checksum is satisfied.

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