The Mapper Murmur3 plugin allows to compute hashes of a field's values at index-time and to store them in the index.
'org.elasticsearch.plugin:mapper-murmur3:2.2.0'
<dependency>
<groupId>org.elasticsearch.plugin</groupId>
<artifactId>mapper-murmur3</artifactId>
<version>2.2.0</version>
</dependency>
<dependency org="org.elasticsearch.plugin" name="mapper-murmur3" rev="2.2.0"/>
"org.elasticsearch.plugin", "mapper-murmur3", "2.2.0"