##! Please refer to the documentation at
##! https://coreruleset.org/docs/development/regex_assembly/.

##! This chained rule is used to match on JWT base64-urlencoded tokens.
##! See https://www.rfc-editor.org/rfc/rfc4648#section-5 for details.

##! JWTs consist of base64-urlencoded encoded JSON, and a JSON structure 
##! just starts with '{"', which becomes 'ey' when encoded with a base64-urlencoded encoder.

##!> define base64-urlencoded-charset [a-zA-Z0-9_-]+
##!> define dot [.]

##!^ ^ey

{{base64-urlencoded-charset}}

##!=>

{{dot}}ey{{base64-urlencoded-charset}}

##!=>

{{dot}}{{base64-urlencoded-charset}}

##!$ $