XML document signing

[gil_mo]

Hi,

Absolute newbie to cryptography.

I'm looking for C++ open source code (to be compiled on Windows, Mac, linux), for doing the following:

1. Generate private+public keys (need not run on all platforms).
2. (server side) Adding a digital signature to an XML document using a private key.
3. (client side) Verifying signature using the matching public key.

I envisage the signed XML to look like this:

<root>
    <creditcard>
        <number>19834209</number>
        <expiry>02/02/2002</expiry>
    </creditcard>
</root>
<Signature>
        WvZUJAJ/3QNqzQvwne2vvy7U5Pck8ZZ5UTa6pIwR7GE+PoGi6A1kyw==
</Signature>

Thanks in advance,
Gil.

[Salem]

cross-posted (for reference)

[raptr_dflo]

If you're storing credit-card numbers, you may also want to encrypt the data (or the entire XML file) in addition to signing it. ;)

As far as generating public and private keys, I recommend PuTTY: http://www.chiark.greenend.org.uk/~sgtatham/putty/