The hash output of bcrypt stops changing after 72 characters but almost all bcrypt documentation mentions a 55 character limit. I'm not quite sure what that is about, can anyone clarify?
check string length
if longer than 55, remove first 55 or less characters up to end of string, store in array
repeat until string is empty
encrypt each item in the array, append them all on to each other as such
EncryptedText[0] . EncryptedText[1]... etc
Seems like a simple way to handle this. You could impose your own restrictions to stop a server DDoS by encryption requests on long strings, but to be honest if you're allowing a 100,000 character password, you're doing it all wrong.