Here i found something in some sources of IAT team (translated from spanish) :
Code:
00509A50 / $ 55 PUSH EBP
((BMD decryption SMD, SOLO SKILLS BMD))
BMD decryption SMD SKILLS.BMD ONLY:
XOR decryption table:
0D1 73 52 0F6 0D2 9A 0CB 27 3E 0AF 59 31 37 0B3 0E7 0A2 [5E] -> Byte changeable then
Decryption with example:
61 xor D1 = B0
B0 - 5E = 52 (number decrypted)
61 3D = 9E (new number that will be exchangeable reemplasado in byte of the XOR table)
And the cycle will repeat byte xoreado prox by 73 and subtracted by the 9E which was reemplaso
5E for the sum of the byte enc 3D.
Mathematical equations:
BE = byte encryption
XT = XorTable (assuming the first byte)
LXT = Last Xor Table (the last byte of the xor table) first see default 5E
LXT-(BE xor XT) = Byte Dec
BE 3D = LXT
Repeat process only that changing to the next byte of XT and using the new LXT
But i guess BMD to SMD you already know the xor decryption .