Re: Is there any asymmetric crypto API to allow decrypting a message but not encrypting it?

From: Andy Chau (wunchun_at_hotmail.com)
Date: 10/04/03 

Date: Sat, 4 Oct 2003 13:49:01 -0700

That is true, but you can say the same for being able to compute the private
key using the public key.

I don't exactly need to use RSA if it cannot do the thing I want, I am just
looking for a asymmetric crypto alg that will fit the following
requirements:

1. Have two set of keys, Key-1 and Key2
2. Person A can use Key-1 to encrypt, but not decrypt
3. Person B can use Key-2 to decrypt, but not encrypt
4. It is computationaly impossible to derive Key-1 from Key-2, and vice
versa

Thanks in advance

Andy

"Pieter Philippaerts" <Pieter@nospam.mentalis.org> wrote in message
news:ec$CDvhiDHA.2452@TK2MSFTNGP10.phx.gbl...
> "Andy Chau" <wunchun@hotmail.com> wrote in message
> > When the client has both private and public key, it can just use the
> public
> > key to encrypt the message which is what I don't want to allow.
>
> With RSA, anyone that has access to the private key can compute the public
> key from that. Hence it is impossible to only give your client access to
the
> private key but not to the public key.
>
> Regards,
> Pieter Philippaerts
> Managed SSL/TLS: http://www.mentalis.org/go.php?sl
>
>

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