Following steps were followed to enable ssl, using a trusted certificate:
1. Created keystore in /home/confluence
2. Import the certificate: root and intermediate in the keystore
$ keytool -import -alias tomcat -file certfile.pem -keystore .keystore
$ keytool -import -alias intermediary -file chain.cer -keystore .keystore
3. Updated server.xml
<Connector port="8443" maxHttpHeaderSize="8192"
maxThreads="150"
minSpareThreads="25"
protocol="org.apache.coyote.http11.Http11NioProtocol"
enableLookups="false"
disableUploadTimeout="true"
acceptCount="100" scheme="https" secure="true"
clientAuth="false"
sslEnabledProtocols="TLSv1,TLSv1.1,TLSv1.2"
SSLEnabled="true"
ciphers="TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, TTLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA256, TLS_RSA_WITH_AES_256_CBC_SHA,SSL_RSA_WITH_RC4_128_SHA" URIEncoding="UTF-8" keystorePass="xxxxx" keystoreFile="/home/confluence1/.keystore" keystoreType="JKS"/>
4. ERR_SSL_VERSION_OR_CIPHER_MISMATCH error after accessing confluence server through port 8443.