A key ring is a file which contains multiple public keys of certificate authority (CA).
A key ring is a file which is necessary for Secure Sockets Layer (SSL) connection over the web. It is securely stored on the server which hosts the website. It contains the public/private key pair for the particular website. It also contains the public/private key pairs from various certificate authorities and the trusted root certificate for the various certification authorities.
An entity or website administrator has to send a certificate signing request (CSR) to the CA. The CA then returns a signed certificate to the entity. This certificate received from the CA has to be stored in the key ring.
References
edit- Joseph Steinberg, Tim Speed, SSL VPN: Understanding, Evaluating, and Planning Secure, Web-based Remote Access, Packt Publishing Ltd, 2005 ISBN 1847190014.