Can somebody tell me how this encryption works:

a b4
aa b4fd
aaa b4fd2f
aaaa b4fd2fdc

b b7
bb b751
bbb b75195
bbbb b7519569

c b6
cc b641
ccc b64164
cccc b641644c

ba b752
abc b4fe49


Thanks!!

~John

dddd b1 76 a3 2d


dcba b1 71 cc 4e
abcd b4 fe 49 f9
ac b4 ff
dcad b1 71 cf d9


dddd b1 76 a3 2d
dcad b1 71 cf d9
abcd b4 fe 49 f9

^^ Here is further stuff I collected