Importing Certificates to the API Microgateway Truststore

For signature validation of JWTs, you need to add the public certificate of the Identity Provider to the truststore of the API Microgateway. Follow the steps given below to import the certificate.

Convert the public certificate to a PEM format. For example,

openssl x509 -inform der -in public_certificate.cert -out certificate.pem

Import the certificate to the truststore. The ballerinaTruststore.p12 resides in the generated distribution of the API Microgateway at <MICROGW_HOME>/runtime/bre/security.
```
keytool -import -keystore <MICROGW_HOME>/runtime/bre/security/ballerinaTruststore.p12 -alias wso2carbonjwt -file certificate.pem
```
Use the keytool that comes in JDK 8u60 or later.

Update the certificateAlias configuration in the micro-gw.conf file residing in the <MICROGW_HOME>/conf directory.
The certificateAlias value is wso2carbonjwt, which is also used in step 2.

[jwtTokenConfig]
issuer="https://localhost:8243/token"
audience="http://org.wso2.apimgt/gateway"
certificateAlias="wso2carbonjwt"
trustStore.path="${ballerina.home}/bre/security/ballerinaTruststore.p12"
trustStore.password="ballerina"