http://dl.ctftime.org/25/43/desc.txt
One more hint:
http://dl.ctftime.org/25/43/hint.txt

1. you have 25 bytes, you work on 22 bytes and 3 bytes separately.
2. flag format = e(22bytes) + e(3bytes)
3. which means d(e(22bytes)) + d(e(3bytes)) must be the same with the binary wor
ds. (have you checked this before? ;)
4. it's base64, there is a possibility that d(x) == d(y)
5. we know you're confused!