# Talk:Asymmetric key algorithm

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## Merge?

This should probably be combined with Public-key cryptography or vice-versa. Rasmus Faber 15:40, 8 Dec 2003 (UTC)

## Error: pure nonsense

Not all asymmetric key algorithms operate in precisely this fashion. The most common have the property that Alice and Bob own two keys; neither of which is (so far as is known) deducible from the other.

Pure nonsense, in most cases it is simple to generate the public key from the private, but the reverse is intended to be VERY hard. Tacvek 23:13, 18 Apr 2005 (UTC)

Are you sure? RSA's two keys are interchangeable: either key can be chosen as the public key. It is very hard to deduce one given the other in any direction. Of course, I'm no expert in the overwhelming majority of asymmetric algorithms, but isn't this how most of them work? Vesta 04:42, 19 Apr 2005 (UTC)
I think I'm correct (not an expert either), and regardless in practive when a private key is stored enough information to generate the public key is stored with it. Gpg for instance allows recreation of 'public key', from 'private key'. Even if key is considered just the number
[1]
DSA for example (as far as i can tell from the page) indicates that all 3 components of the public key are required for signing, which makes the public key part of the private for all real intents and purposes. (Note that that is actually only signing, not full encyption.)
As for RSA using either key i would assume that there is a reason key e is given out publicly, rather than key d. I suspect it has to do with the fact that e is restricted to 1<e<φ, while key e is not restricted in any such way. Presumably this is because it is significantly easier to find e (public) from d (private) than d (private) from e (public).
The final word though is that while perhaps in theory one cannot be easilly derived from the other, in practice the information needed for getting the public key is almost always stored with the private key. I suspect the article sould reflect this fact rather than the misleading one currently there. Tacvek 22:28, 19 Apr 2005 (UTC)
Your argument sounds good. If nobody else objects, I'd say that you're in the right to go ahead and change it. Vesta 06:17, 20 Apr 2005 (UTC)