#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?s)public_key=#STARTKEY#(.*)#ENDKEY#"
Local $sString = "public_key=#STARTKEY#c3NoLXJzYSBBQUFBQjNOemFDMXljMkVBQUFBREFRQUJBQUFCZ1FEWVZVZDY5eVBDS2hvejdjMUI5" & @CRLF & _
"dWx0TStNZmpRR3BnZG9xZGhFTDRKVStsRkt5OFpwazVTdy9Ic3RlVnZvZm5qbGlLajRjNWNXbzdr" & @CRLF & _
"NEZUSy81dzZCcXlmSHpkcnFSRHNWbHNWOERLSUpJejBrTFJoMUFHdlQ3c1lWcXpwNUhFcnN4ZnZI" & @CRLF & _
"K0pEZlNVa0pUOElTWE4xSkxkcllxUjJzQVBmMjhsbVl1eXpkaGprQTNzdWZlZ2dQQWYzam1ndFFP" & @CRLF & _
"Q1JHWi9ZdmZKcjFLcVZIZDdvYUdOOE1Ndm9BMy9reE9iTWVCSk5ldkl5VHNwdWF2bWxGU29qMkVU" & @CRLF & _
"Z12RGeUphQ0FGamQ3VFF2ZXJGM0JSeUVxNDhDMUR4OTE3cWJvRVJaQXZ6elQxU0lIZHk2MG5QVHpa" & @CRLF & _
"OEM5akRxbzZlVmJYNk8xT05ZckViM0eYhRlmk0WkpjMWcvRi83WVA3SHVhSy91V0llb2JkN2JNRmtj" & @CRLF & _
"NFNhSlJxRE1JNE9ERFdzSHhKL29ZalZrL1VrU1dqSXJZTVBaUDA4VW1XaVljcHh4cFF6YmZKb3pH" & @CRLF & _
"bmNqMEFodUlqZzQ3blJwMTJTUWY5cDRnQ1UzK2NxdVNPQmZjTXExd0ZHcXVxMEk0ZEVIdCtiNmZi" & @CRLF & _
"OFpmYll1Z0lpa2xRZUlYMzQ4cnl2aFpzaVQvZ3AvRllSaFZEZTA9IG5pY2NoYXVkQGNpc2NvLmNv" & @CRLF & _
"bUBOSUNDSEFVRC1NLUZCVE4K#ENDKEY#"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($aArray, "Result")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm