Key stores allow you to manage the keys that are stored in a database. A Key store must contain a key pair with a certificate signed by a trusted Certification Authority (CA). A CA is an entity trusted by all parties participating in a secure communication. This entity will certify a trusted party's public keys by signing them. Since the certificate authority is a trusted one, it will accept the public key certificates signed by that particular CA as trusted.
The WSO2 Identity Server allows you to add a Key store, view a Key store, and import a certificate for a Key store.