Function at 0x4bb7b0
Capabilities:
Encrypt data using rc4 ksa

Disassembly:
push ebp
mov ebp, esp
sub esp, 0x6c
mov eax, dword [0x59e074]
xor eax, ebp
mov dword [ebp - 4], eax
mov eax, dword [ecx]
lea edx, [ebp - 0x14]
push ebx
push esi
push edi
push 8
push edx
mov dword [ebp - 0x68], ecx
call dword [eax]
mov dword [ebp - 0xc], 0x474e5089
lea ecx, [ebp - 0x14]
mov dword [ebp - 8], 0xa1a0a0d
lea edx, [ebp - 0xc]
mov esi, 4
nop dword [eax]
mov eax, dword [ecx]
cmp eax, dword [edx]
jne 0x4bb805
add ecx, 4
add edx, 4
sub esi, 4
jae 0x4bb7f0
xor eax, eax
jmp 0x4bb82a
cmp al, byte [edx]
jne 0x4bb825
mov al, byte [ecx + 1]
cmp al, byte [edx + 1]
jne 0x4bb825
mov al, byte [ecx + 2]
cmp al, byte [edx + 2]
jne 0x4bb825
mov al, byte [ecx + 3]
cmp al, byte [edx + 3]
jne 0x4bb825
xor eax, eax
jmp 0x4bb82a
sbb eax, eax
or eax, 1
test eax, eax
jne 0x4bb8cb
sub esp, 8
call fcn.004e85d0
mov esi, eax
add esp, 8
mov dword [ebp - 0x48], esi
test esi, esi
jne 0x4bb84a
xor edi, edi
jmp 0x4bb87f
mov eax, dword [esi + 0x278]
push 0x12c
test eax, eax
je 0x4bb861
push esi
call eax
add esp, 8
jmp 0x4bb869
call fcn.00512c46
add esp, 4
mov edi, eax
test edi, edi
je 0x4bb87f
push 0x12c
push 0
push edi
call fcn.0050c400
add esp, 0xc
push ecx
mov ecx, esi
mov dword [ebp - 0x54], edi
call fcn.004e8470
add esp, 4
push 0
push eax
call fcn.00530bd0
mov esi, dword [ebp - 0x48]
add esp, 8
test eax, eax
je 0x4bb8de
test esi, esi
je 0x4bb8cb
xor edx, edx
mov ecx, esi
call fcn.004ea060
lea edx, [ebp - 0x54]
mov ecx, esi
call fcn.004ea060
mov ecx, esi
mov dword [ebp - 0x48], 0
call fcn.004e9380
mov ecx, esi
call fcn.004ef740
xor eax, eax
pop edi
pop esi
pop ebx
mov ecx, dword [ebp - 4]
xor ecx, ebp
call fcn.00509af6
mov esp, ebp
pop ebp
ret
mov dword [ebp - 0x38], esi
test esi, esi
je 0x4bb920
mov eax, dword [ebp - 0x68]
mov dword [esi + 0x60], eax
mov dword [esi + 0x5c], 0x4bb780
cmp dword [esi + 0x58], 0
je 0x4bb90b
mov edx, str.Cant_set_both_read_data_fn_and_write_data_fn_in_the_same_structure
mov dword [esi + 0x58], 0
mov ecx, esi
call fcn.004e8100
mov dword [esi + 0x174], 0
test esi, esi
je 0x4bb920
mov byte [esi + 0x155], 8
cmp byte [esi + 0x150], 8
mov edi, dword [ebp - 0x54]
mov dword [ebp - 0x6c], edi
jb 0x4bb93e
cmp byte [esi + 0x14f], 3
je 0x4bb93e
test byte [edi + 8], 0x10
je 0x4bb945
mov ecx, esi
call fcn.004e3e10
push 1
mov edx, 0xff
mov ecx, esi
call fcn.004e9630
mov eax, dword [esi + 0x7c]
add esp, 4
test eax, 0x8000
je 0x4bb968
or eax, 0x1000000
mov dword [esi + 0x7c], eax
cmp byte [esi + 0x14c], 0
je 0x4bb977
or eax, 2
mov dword [esi + 0x7c], eax
mov ecx, esi
call fcn.004e3e50
mov eax, dword [esi + 0x78]
test al, 0x40
je 0x4bb99e
mov edx, str.invalid_after_png_start_read_image_or_png_read_update_info
mov ecx, esi
test eax, 0x400000
je 0x4bbf3e
call fcn.004e8100
jmp 0x4bb9ad
or eax, 0x4000
or dword [esi + 0x7c], 0x400
mov dword [esi + 0x78], eax
mov edx, edi
mov ecx, esi
call fcn.004e8630
mov edx, edi
mov ecx, esi
call fcn.004e8b00
mov ebx, dword [esi + 0x100]
mov eax, dword [esi + 0x104]
shl ebx, 2
imul eax, ebx
push 0x18
mov dword [ebp - 0x20], ebx
mov dword [ebp - 0x24], eax
call fcn.00512c46
mov ecx, eax
add esp, 4
mov dword [ebp - 0x30], ecx
mov dword [ecx], 0
mov dword [ecx + 4], 0
mov dword [ecx + 0x10], 0
mov dword [ecx + 0x14], 0
mov eax, dword [esi + 0x100]
mov edx, dword [esi + 0x104]
mov dword [ecx + 8], eax
mov eax, ebx
mov dword [ecx + 0xc], edx
xor ecx, ecx
mov dword [ebp - 0x34], edx
mul edx
seto cl
neg ecx
or ecx, eax
push ecx
call fcn.00512c46
add esp, 4
mov dword [ebp - 0x40], eax
push dword [ebp - 0x24]
push 0
push eax
call fcn.0050c400
mov eax, dword [ebp - 0x34]
xor ecx, ecx
add esp, 0xc
mov edx, 4
mul edx
seto cl
neg ecx
or ecx, eax
push ecx
call fcn.00512c46
mov edx, eax
add esp, 4
mov eax, dword [ebp - 0x34]
xor ecx, ecx
mov dword [ebp - 0x44], edx
test eax, eax
jle 0x4bba80
mov edx, dword [ebp - 0x40]
mov esi, dword [ebp - 0x44]
nop dword [eax]
mov dword [esi + ecx*4], edx
inc ecx
add edx, ebx
cmp ecx, eax
jl 0x4bba70
mov esi, dword [ebp - 0x38]
mov edx, dword [ebp - 0x44]
test edi, edi
je 0x4bbece
mov eax, dword [edi + 8]
and eax, 0x10000
je 0x4bbece
mov eax, dword [ebp - 0x30]
xor ecx, ecx
mov edx, dword [edi + 0x10c]
mov dword [ebp - 0x34], edx
mov dword [eax + 0x10], edx
mov eax, dword [ebp - 0x24]
mul edx
seto cl
neg ecx
or ecx, eax
push ecx
call fcn.00512c46
add esp, 4
mov dword [ebp - 0x58], eax
push dword [ebp - 0x24]
call fcn.00512c46
add esp, 4
mov dword [ebp - 0x3c], eax
push dword [ebp - 0x24]
push 0
push eax
call fcn.0050c400
mov eax, dword [ebp - 0x30]
add esp, 0xc
mov ecx, dword [edi + 0x110]
mov edx, 2
mov dword [eax + 0x14], ecx
xor ecx, ecx
mov eax, dword [ebp - 0x34]
mul edx
seto cl
neg ecx
or ecx, eax
push ecx
call fcn.00512c46
mov ecx, eax
mov dword [ebp - 0x1c], 0
mov eax, dword [ebp - 0x30]
add esp, 4
cmp dword [ebp - 0x34], 0
mov dword [ebp - 0x5c], ecx
mov dword [eax + 4], ecx
jle 0x4bbeb0
mov eax, dword [ebp - 0x58]
mov dword [ebp - 0x4c], eax
sub eax, dword [ebp - 0x24]
mov dword [ebp - 0x50], eax
nop dword [eax + eax]
mov eax, dword [esi + 0x74]
test eax, 0x10000
je 0x4bbf4f
cmp dword [esi + 0x260], 0
je 0x4bbc24
and dword [esi + 0x78], 0xffffffbf
and eax, 0xfffdfff3
mov dword [esi + 0x118], 0
mov byte [esi + 0x14d], 0
mov dword [esi + 0x74], eax
mov byte [ebp - 0x15], 0
nop dword [eax]
mov ecx, esi
call fcn.004ef9e0
mov ebx, eax
mov eax, dword [esi + 0x11c]
cmp eax, 0x49444154
jne 0x4bbba8
cmp byte [ebp - 0x15], 0
jne 0x4bbf37
cmp dword [esi + 0x260], 1
ja 0x4bbf37
mov edx, ebx
mov ecx, esi
call fcn.004efb60
jmp 0x4bbb70
mov ecx, esi
cmp eax, 0x6663544c
jne 0x4bbbc2
push ebx
mov edx, edi
call fcn.004f3390
add esp, 4
mov byte [ebp - 0x15], 1
jmp 0x4bbb70
cmp eax, 0x66644154
jne 0x4bbbeb
mov edx, ebx
call fcn.004f3670
cmp byte [ebp - 0x15], 0
jne 0x4bbc03
cmp dword [esi + 0x260], 1
jbe 0x4bbc03
lea edx, [ebx - 4]
mov ecx, esi
call fcn.004efb60
jmp 0x4bbb70
mov edx, str.Skipped__ignored__a_chunk_between_APNG_chunks
call fcn.004e8100
mov edx, ebx
mov ecx, esi
call fcn.004efb60
jmp 0x4bbb70
mov ecx, dword [esi + 0x74]
test ecx, 0x20000
je 0x4bbf43
lea eax, [ebx - 4]
or ecx, 4
mov ebx, dword [ebp - 0x20]
mov dword [esi + 0x134], eax
mov dword [esi + 0x74], ecx
push 0x20000
mov edx, edi
mov ecx, esi
call fcn.004e9b70
add esp, 4
test eax, eax
je 0x4bbcb1
movzx ecx, word [edi + 0x126]
movzx eax, word [edi + 0x124]
test cx, cx
je 0x4bbca5
cmp ecx, 0x64
je 0x4bbca5
mov edx, dword [ebp - 0x30]
mov edx, dword [edx + 4]
cmp ecx, 0xa
jne 0x4bbc6a
mov ecx, dword [ebp - 0x1c]
lea eax, [eax + eax*4]
add eax, eax
mov word [edx + ecx*2], ax
jmp 0x4bbcbd
mov ebx, dword [ebp - 0x1c]
mov dword [ebp - 0x28], eax
lea edx, [edx + ebx*2]
mov ebx, dword [ebp - 0x20]
mov dword [ebp - 0x2c], edx
mov edx, 0x3e8
cmp cx, dx
jne 0x4bbc96
mov ecx, dword [ebp - 0x2c]
mov eax, 0xcccccccd
mul dword [ebp - 0x28]
shr edx, 3
mov word [ecx], dx
jmp 0x4bbcbd
imul eax, eax, 0x64
xor edx, edx
div ecx
mov ecx, dword [ebp - 0x2c]
mov word [ecx], ax
jmp 0x4bbcbd
mov ecx, dword [ebp - 0x1c]
mov edx, dword [ebp - 0x5c]
mov word [edx + ecx*2], ax
jmp 0x4bbcbd
mov eax, dword [ebp - 0x1c]
xor edx, edx
mov ecx, dword [ebp - 0x5c]
mov word [ecx + eax*2], dx
mov edx, dword [ebp - 0x44]
mov ecx, esi
call fcn.004e8fa0
mov ecx, dword [edi + 0x120]
mov eax, dword [edi + 0x11c]
imul ecx, ebx
add ecx, dword [ebp - 0x3c]
lea ebx, [ecx + eax*4]
movzx eax, byte [edi + 0x129]
mov ecx, dword [ebp - 0x40]
mov dword [ebp - 0x64], ebx
mov dword [ebp - 0x2c], ecx
sub eax, 0
je 0x4bbdc7
sub eax, 1
jne 0x4bbe0c
mov dword [ebp - 0x28], eax
cmp dword [edi + 0x118], eax
jbe 0x4bbe0c
mov edx, dword [edi + 0x114]
mov dword [ebp - 0x60], 0
mov esi, ecx
test edx, edx
je 0x4bbda6
movzx edx, byte [esi + 3]
lea ebx, [ebx + 4]
movzx ecx, byte [esi]
lea esi, [esi + 4]
movzx eax, byte [ebx - 4]
mov edi, 0xff
imul ecx, edx
sub edi, edx
imul eax, edi
add ecx, eax
sar ecx, 8
mov byte [ebx - 4], cl
movzx ecx, byte [esi - 3]
movzx eax, byte [ebx - 3]
imul ecx, edx
imul eax, edi
add ecx, eax
sar ecx, 8
mov byte [ebx - 3], cl
movzx ecx, byte [esi - 2]
movzx eax, byte [ebx - 2]
imul ecx, edx
imul eax, edi
add ecx, eax
sar ecx, 8
mov byte [ebx - 2], cl
movzx ecx, byte [esi - 1]
movzx eax, byte [ebx - 1]
imul eax, edi
mov edi, dword [ebp - 0x6c]
imul ecx, edx
add ecx, eax
mov eax, dword [ebp - 0x60]
sar ecx, 8
inc eax
mov byte [ebx - 1], cl
mov edx, dword [edi + 0x114]
mov dword [ebp - 0x60], eax
cmp eax, edx
jb 0x4bbd24
mov ecx, dword [ebp - 0x2c]
mov eax, dword [ebp - 0x28]
mov ebx, dword [ebp - 0x64]
inc eax
add ebx, dword [ebp - 0x20]
add ecx, dword [ebp - 0x20]
mov dword [ebp - 0x64], ebx
mov dword [ebp - 0x2c], ecx
mov dword [ebp - 0x28], eax
cmp eax, dword [edi + 0x118]
jb 0x4bbd13
jmp 0x4bbe09
cmp dword [edi + 0x118], 0
mov dword [ebp - 0x28], 0
jbe 0x4bbe0c
mov esi, dword [ebp - 0x28]
nop word [eax + eax]
mov eax, dword [edi + 0x114]
shl eax, 2
push eax
push ecx
push ebx
call fcn.0050be80
mov ecx, dword [ebp - 0x2c]
inc esi
add ecx, dword [ebp - 0x20]
add esp, 0xc
add ebx, dword [ebp - 0x20]
mov dword [ebp - 0x2c], ecx
cmp esi, dword [edi + 0x118]
jb 0x4bbde0
mov esi, dword [ebp - 0x38]
push dword [ebp - 0x24]
push dword [ebp - 0x3c]
push dword [ebp - 0x4c]
call fcn.0050be80
mov ecx, dword [edi + 0x120]
add esp, 0xc
mov ebx, dword [ebp - 0x20]
mov edx, dword [ebp - 0x3c]
mov eax, dword [edi + 0x11c]
imul ecx, ebx
add ecx, edx
lea eax, [ecx + eax*4]
mov dword [ebp - 0x28], eax
movzx eax, byte [edi + 0x128]
sub eax, 1
je 0x4bbe63
sub eax, 1
mov eax, dword [ebp - 0x1c]
jne 0x4bbe9a
test eax, eax
jle 0x4bbe9a
push dword [ebp - 0x24]
push dword [ebp - 0x50]
push edx
call fcn.0050be80
add esp, 0xc
jmp 0x4bbe97
xor ebx, ebx
cmp dword [edi + 0x118], ebx
jbe 0x4bbe94
mov esi, dword [ebp - 0x28]
mov eax, dword [edi + 0x114]
shl eax, 2
push eax
push 0
push esi
call fcn.0050c400
add esi, dword [ebp - 0x20]
inc ebx
add esp, 0xc
cmp ebx, dword [edi + 0x118]
jb 0x4bbe70
mov esi, dword [ebp - 0x38]
mov ebx, dword [ebp - 0x20]
mov eax, dword [ebp - 0x1c]
mov ecx, dword [ebp - 0x24]
inc eax
add dword [ebp - 0x4c], ecx
add dword [ebp - 0x50], ecx
mov dword [ebp - 0x1c], eax
cmp eax, dword [ebp - 0x34]
jl 0x4bbb30
push dword [ebp - 0x3c]
call fcn.0050f4d7
add esp, 4
push dword [ebp - 0x40]
call fcn.0050f4d7
mov ebx, dword [ebp - 0x30]
add esp, 4
mov eax, dword [ebp - 0x58]
jmp 0x4bbee2
mov ecx, esi
call fcn.004e8fa0
mov ebx, dword [ebp - 0x30]
mov eax, dword [ebp - 0x40]
mov dword [ebx + 0x10], 1
push dword [ebp - 0x44]
mov dword [ebx], eax
call fcn.0050f4d7
add esp, 4
mov edx, edi
mov ecx, esi
call fcn.004e9070
test esi, esi
je 0x4bbf24
xor edx, edx
mov ecx, esi
call fcn.004ea060
lea edx, [ebp - 0x54]
mov ecx, esi
call fcn.004ea060
mov ecx, esi
mov dword [ebp - 0x48], 0
call fcn.004e9380
mov ecx, esi
call fcn.004ef740
mov ecx, dword [ebp - 4]
mov eax, ebx
pop edi
pop esi
xor ecx, ebp
pop ebx
call fcn.00509af6
mov esp, ebp
pop ebp
ret
mov edx, str.png_read_frame_head__:_out_of_place_IDAT
mov ecx, esi
call fcn.004e80d0
mov edx, str.png_read_frame_head__:_out_of_place_fdAT
mov ecx, esi
call fcn.004e80d0
mov edx, str.attempt_to_png_read_frame_head___but_no_acTL_present
mov ecx, esi
call fcn.004e80d0
int3