International Journal of Research and Computational Technology (IJRCT)
In a public key infrastructure, a certificate specifies a binding between a name and a public key or other attributes. Over time, public keys and attributes can change: a private key might be compromised, leading to selection of a new public key, for example. The old binding and any certificate that specifies that binding then become invalid. A Certification Authority (CA) attests to the validity of bindings by issuing digitally signed certificates that specify these bindings and by providing a means for clients to check the validity of certificates.