Re: Decrypt messages received from different senders


Peter Pearson wrote:
On 20 Dec 2006 07:25:45 -0800, Sergei <silentser@xxxxxxxxx> wrote:

Paul Rubin wrote:
"Sergei" <silentser@xxxxxxxxx> writes:
Is there is a way to make the receiver able to decrypt the messages in
a more efficient manner than just trying all the keys and checking
which gives the valid message?

Have the receiver make a public/private key pair. Give the receiver's
public key to all the senders, so they all use it.

The problem is that the senders should not share the key. An encrypted
message should be hidden from everyone, but the receiver and the sender
who sent it.

The encrypted message is still hidden from everyone when
the public key is shared. That's the point of public-key
cryptography.

--
To email me, substitute nowhere->spamcop, invalid->net.

Ok, but such scenario does not allow the senders to reuse messages. Is
it possible to implement it in such a way, that the senders can also
decrypt the messages that they issue.

Imagine that the encrypted message is written to some data carrier and
that both the sender and the receiver should be able to read it. For
the sender it is not a problem, but for the receiver, who might have
got this data carrier form several sources, arises the problem of
finding a valid key.

Best regards,
Sergei

.

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