In this project, I was required to use a custom password encryption algorithm. The spring-security plugin uses the 'SHA-256' algorithm by default. This can be changed to use other standard algorithms (MD2, MD5 etc.) by adding the following lines (if, for example, MD5 encoding is required) in /grails-app/conf/Config.groovy:
grails.plugins.springsecurity.password.algorithm="MD5"But what I wanted was to use a custom algorithm of our own, not the standard ones. Fortunately, this is again, very easy. Because of Spring's dependency injection, we can easily create our own password encoder and inject it. The steps to do the same are explained here.