That's right. The use of crypto for signatures mirrors it's use for secrecy. You generate a message digest or hash value from the text you want to sign and encrypt this using your private key. A recipient extracts the hash using the your public key and compares this with a hash value calculated locally. If they match it proves that the text hasn't been changed since it was signed and that it was signed by someone with access to the signers private key (hopefully owner the owner)
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Ewan Davis - Personal email address [log in to unmask] Also at [log in to unmask]
PGP key available from ldap://certserver.pgp.com
Work Phone numbers
Voice +44 (1) 527 579414 Fax +44(1)527 833188
Affiliations:
Chairman AAH Meditel (www.meditel.co.uk) supplier of primary care information systems.
Chairman PharMed (www.PharMed.org.uk) Promoting GP-Pharmacy links
Chairman CSSA Primary Care Group (www.cssa.co.uk) the trade association of GP System suppliers.
-----Original Message-----
From: Chris Salter [SMTP:[log in to unmask]]
Sent: Saturday, November 14, 1998 12:13 PM
To: [log in to unmask]
Subject: All you wanted to know about cyptogrphy but were affraid to ask. WAS PGP message
In article <[log in to unmask]>, dated Sat, 14 Nov
1998 at 09:04:11, Ewan Davis <[log in to unmask]> writes
>No, you haven't quite understood PGP. You need the private key of the intended
>recipient to read an encrypted message not the public key of the sender.
[snip supporting explanation]
I think the poster may have been confusing PGP encryption with PGP
digital signatures. My PGP is a little rusty but I believe that PGP
signed mail can be verified using the authors public key.
Chris
--
Chris Salter (Vice Chairman) Lincolnshire Post-Polio Network
Registered Charity No. 1064177
<URL:http://www.zynet.co.uk/ott/polio/lincolnshire/>
Web Site & Vice Chairman Email: [log in to unmask]
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