List entrys in truststore:
$ keytool -v -list -keystore truststore.ts -storepass password
Select the alias that can be exported to the Internet RFC 1421 standard. The option '-exportcert' reads (from the truststore) the certificate associated with alias, and stores it in the file outFile.
keytool -exportcert -alias entryAlias -file outFile -keystore truststore.ts -rfc -storepass password
Averiguate the hash of the cert
$ openssl x509 -subject_hash_old -noout -in cert