Chuck Pareto wrote:

> I'm not sure what you mean by "shouldn't be using public-key
> encryption", why?

Because you don't understand its properties, so there's no way you can know
whether or not it meets your security requirements.

> It seems like .Net sets up a nice class that is easily
> implemented, all I need is the key and the exponent and I can
> encrypt and decrypt when needed.

Right, except you don't get any security.

> I don't think I really have a choice about what to use, I recently
> started in a group that has a public and private key they are using
> to encrypt and then decrypt strings of data.

Which is fine if, for example, those strings of data are randomly-chosen
keys for a symmetric cipher. It is, however, not fine if those strings are
messages.

> I don't think I can change that. What would be the advantages of doing
> what you suggest and using symmetric encryption to encrypt and PK
> encryption for encrypting the key?

The advantage would be that if you have reasonable security objectives,
there's a good chance the algorithm would meet them. Numerous attacks
against RSA are known -- RSA is just an algorithm, it is not a scheme -- and
you need a well-designed cryptographic scheme to meet actual security
requirements.

http://crypto.stanford.edu/~dabo/abstracts/RSAattack-survey.html


> I don't think we have a symmetric key because we are using RSA with
> a public and private key.

That's a non-sequiter. The public and private key could be being used to
encipher and decipher the symmetric key. This is the normal approach.

> If you think your approach is better please let me know and I will
> discuss it with my group and see if we can make a change.

If your group includes a security expert, this kind of stuff would already
be done. If it doesn't, the likelihood of this making things any better
isn't really all that great.

DS

______________________________________________________________________
OpenSSL Project                                 http://www.openssl.org
User Support Mailing List                    openssl-users@openssl.org
Automated List Manager                           majord...@openssl.org

Reply via email to