In this mission you are given a kindergarten-encrypted password, and you need to reverse-engineer the encryption.
You'll notice that if you encrypt "aaaaa" it gives you "abcde". This encryption simply adds the character number to the character, starting at 0.
You can use http://www.asciitable.com/ to find the progression of symbols. Ex. if your encrypted password is "968d<56>" you need to subtract 1 from the second letter, 2 from the third, and three from the fourth, producing "956a". It isn't obvious what < goes to, so use the link to find out that it is "8". Continuing, you end up with "956a8007", which correctly "encrypts" to "968d<56>".
A little tool made by mys3c0ndw0rld to decrypt the password : DecryptME Basic6