Look this is example rewrite apache
RewriteRule
^[A-Z]{3}[a-z]{2}[0-9]{4}[a-z]{3}[0-9]{4}[A-Z]{2}[a-z]{1}[0-9]{1}/(.+)$
files/$1
3 characters A-Z
2 characters a-z
4characters 0-9
u know?
and last code is
ADDad0000asa0000AAp0
QJNqq0821sxz4230QAp0
Posted at Nginx Forum: http://forum.nginx.org/read.php?2,190307,190319#msg-190319