Function at 0x51dc70
Capabilities:
Encode data using xor
Hash data with crc32

Disassembly:
push esi
mov esi, edx
not eax
test esi, esi
je 0x51d9c0
lea esp, [esp]
test cl, 3
je 0x51d9c0
movzx edx, byte [ecx]
xor edx, eax
and edx, 0xff
shr eax, 8
xor eax, dword [edx*4 + 0x6496e0]
inc ecx
sub esi, 1
jne 0x51d9a0
push ebx
push edi
cmp esi, 0x20
jb 0x51dbeb
mov edi, esi
shr edi, 5
xor eax, dword [ecx]
add ecx, 4
mov edx, eax
shr edx, 0x10
mov ebx, eax
shr ebx, 8
and edx, 0xff
mov edx, dword [edx*4 + 0x649ae0]
and ebx, 0xff
xor edx, dword [ebx*4 + 0x649ee0]
mov ebx, eax
shr ebx, 0x18
xor edx, dword [ebx*4 + 0x6496e0]
and eax, 0xff
xor edx, dword [eax*4 + 0x64a2e0]
add ecx, 4
xor edx, dword [ecx - 4]
add ecx, 4
mov eax, edx
shr eax, 0x10
mov ebx, edx
shr ebx, 8
and eax, 0xff
mov eax, dword [eax*4 + 0x649ae0]
and ebx, 0xff
xor eax, dword [ebx*4 + 0x649ee0]
mov ebx, edx
shr ebx, 0x18
xor eax, dword [ebx*4 + 0x6496e0]
and edx, 0xff
xor eax, dword [edx*4 + 0x64a2e0]
add ecx, 4
xor eax, dword [ecx - 8]
add ecx, 4
mov edx, eax
shr edx, 0x10
mov ebx, eax
and edx, 0xff
mov edx, dword [edx*4 + 0x649ae0]
shr ebx, 8
and ebx, 0xff
xor edx, dword [ebx*4 + 0x649ee0]
mov ebx, eax
shr ebx, 0x18
xor edx, dword [ebx*4 + 0x6496e0]
and eax, 0xff
xor edx, dword [eax*4 + 0x64a2e0]
add ecx, 4
xor edx, dword [ecx - 0xc]
mov eax, edx
shr eax, 0x10
mov ebx, edx
shr ebx, 8
and eax, 0xff
mov eax, dword [eax*4 + 0x649ae0]
and ebx, 0xff
xor eax, dword [ebx*4 + 0x649ee0]
mov ebx, edx
shr ebx, 0x18
xor eax, dword [ebx*4 + 0x6496e0]
and edx, 0xff
xor eax, dword [edx*4 + 0x64a2e0]
xor eax, dword [ecx - 8]
mov edx, eax
shr edx, 0x10
mov ebx, eax
and edx, 0xff
mov edx, dword [edx*4 + 0x649ae0]
shr ebx, 8
and ebx, 0xff
xor edx, dword [ebx*4 + 0x649ee0]
mov ebx, eax
shr ebx, 0x18
xor edx, dword [ebx*4 + 0x6496e0]
and eax, 0xff
xor edx, dword [eax*4 + 0x64a2e0]
xor edx, dword [ecx - 4]
mov eax, edx
shr eax, 0x10
and eax, 0xff
mov ebx, edx
mov eax, dword [eax*4 + 0x649ae0]
shr ebx, 8
and ebx, 0xff
xor eax, dword [ebx*4 + 0x649ee0]
mov ebx, edx
shr ebx, 0x18
xor eax, dword [ebx*4 + 0x6496e0]
and edx, 0xff
xor eax, dword [edx*4 + 0x64a2e0]
add ecx, 4
xor eax, dword [ecx - 4]
add ecx, 4
mov edx, eax
mov ebx, eax
shr edx, 0x10
shr ebx, 8
and edx, 0xff
mov edx, dword [edx*4 + 0x649ae0]
and ebx, 0xff
xor edx, dword [ebx*4 + 0x649ee0]
mov ebx, eax
shr ebx, 0x18
xor edx, dword [ebx*4 + 0x6496e0]
and eax, 0xff
xor edx, dword [eax*4 + 0x64a2e0]
sub esi, 0x20
xor edx, dword [ecx - 4]
mov eax, edx
shr eax, 0x10
and eax, 0xff
mov eax, dword [eax*4 + 0x649ae0]
mov ebx, edx
shr ebx, 8
and ebx, 0xff
xor eax, dword [ebx*4 + 0x649ee0]
mov ebx, edx
shr ebx, 0x18
xor eax, dword [ebx*4 + 0x6496e0]
and edx, 0xff
xor eax, dword [edx*4 + 0x64a2e0]
sub edi, 1
jne 0x51d9d0
cmp esi, 4
jb 0x51dc40
mov edx, esi
shr edx, 2
xor eax, dword [ecx]
add ecx, 4
mov edi, eax
shr edi, 0x10
and edi, 0xff
mov edi, dword [edi*4 + 0x649ae0]
mov ebx, eax
shr ebx, 8
and ebx, 0xff
xor edi, dword [ebx*4 + 0x649ee0]
mov ebx, eax
shr ebx, 0x18
xor edi, dword [ebx*4 + 0x6496e0]
and eax, 0xff
xor edi, dword [eax*4 + 0x64a2e0]
sub esi, 4
sub edx, 1
mov eax, edi
jne 0x51dbf5
pop edi
pop ebx
test esi, esi
je 0x51dc6b
jmp 0x51dc50
movzx edx, byte [ecx]
xor edx, eax
and edx, 0xff
shr eax, 8
xor eax, dword [edx*4 + 0x6496e0]
inc ecx
sub esi, 1
jne 0x51dc50
not eax
pop esi
ret
mov ecx, dword [esp + 8]
test ecx, ecx
jne 0x51dc7b
xor eax, eax
ret
mov edx, dword [esp + 0xc]
mov eax, dword [esp + 4]
jmp 0x51d990