My company provides its services as web pages and web services to our customers.

Once a year we update the certificate used for the https connections.

I notified the update to the clients that use the web services.

One of them asked me a copy of the public key.

No problem. Open the web site with the browser, save the key and send by email.

One day later the client asked me the public key in a zip file because the anti virus blocked my attachment.

Why the client hates the Chain of Trust ?
He could obtain the public key by them self from the browser or openssl.