def str ='<Identifier Authority="iso6523-actorid-upis">[plc]originalSender[plc]</Identifier>'
String originalSender = '9928:12341234A'
def result = str.replaceAll("\\[plc\\]originalSender\\[plc\\]", originalSender)
println str
println result
ZGVmIHN0ciA9JzxJZGVudGlmaWVyIEF1dGhvcml0eT0iaXNvNjUyMy1hY3RvcmlkLXVwaXMiPltwbGNdb3JpZ2luYWxTZW5kZXJbcGxjXTwvSWRlbnRpZmllcj4nCgpTdHJpbmcgb3JpZ2luYWxTZW5kZXIgPSAnOTkyODoxMjM0MTIzNEEnCgpkZWYgcmVzdWx0ID0gc3RyLnJlcGxhY2VBbGwoIlxcW3BsY1xcXW9yaWdpbmFsU2VuZGVyXFxbcGxjXFxdIiwgb3JpZ2luYWxTZW5kZXIpCgpwcmludGxuIHN0cgpwcmludGxuIHJlc3VsdA==