What encoding scheme is this?

问题

I have found the following encoding scheme in the POST requests at a login screen. On the left is what I typed in the password field, on the right is what was passed to the server:

aaaaaaaaaa -> %5BYHj%5BYHj%5BYHj%5BS%3F%3F
bbbbbbbbbb -> %5BoLk%5BoLk%5BoLk%5Bi%3F%3F
hello -> cIXudI%3A%3F
doggie -> %5CI%3Bp%5C4nn
abcdefghilk12345678 -> %5BYLl%5CIXo%5C4jrdIuzOlO2PV%5B5QC%3F%3F

What encoding scheme is this?

来源：https://stackoverflow.com/questions/28158842/what-encoding-scheme-is-this