Function at 0x42bf20
Capabilities:
Create new key via cryptacquirecontext
Decode data using base64 via winapi
Encrypt or decrypt via wincrypt

Disassembly:
push 0xffffffffffffffff
push 0x4d7ba6
mov eax, dword fs:[0]
push eax
mov eax, 0xe8
call fcn.00468d20
mov eax, dword [0x5808f0]
xor eax, esp
mov dword [esp + 0xe4], eax
push ebx
push ebp
push esi
push edi
mov eax, dword [0x5808f0]
xor eax, esp
push eax
lea eax, [esp + 0xfc]
mov dword fs:[0], eax
xor ebp, ebp
xor eax, eax
mov ebx, ecx
mov dword [esp + 0x40], 7
mov dword [esp + 0x3c], ebp
mov word [esp + 0x2c], ax
lea ecx, [esp + 0x14]
push ecx
mov dword [esp + 0x108], ebp
call fcn.0041ae00
add esp, 4
test eax, eax
jne 0x42bfb8
push 0x4e4598
call fcn.0041a700
add esp, 4
cmp dword [esp + 0x40], 8
jb 0x42c323
mov edx, dword [esp + 0x2c]
push edx
call fcn.004699ce
add esp, 4
jmp 0x42c323
mov esi, dword [sym.imp.ADVAPI32.dll_CryptAcquireContextA]
push 0x10
push 0x18
push ebp
push ebp
lea edi, [ebx + 0x24]
push edi
call esi
push 8
push 0x18
push ebp
push ebp
push edi
call esi
test eax, eax
jne 0x42c026
call dword [sym.imp.KERNEL32.dll_GetLastError]
push eax
push str.Error_acquiring_context__0x_X__n
push 0x3ff
push 0x584090
call fcn.00469c7b
push 0x584090
call fcn.0041a5a0
mov eax, dword [esp + 0x28]
push eax
call fcn.004690f0
add esp, 0x18
cmp dword [esp + 0x40], 8
jb 0x42c323
mov ecx, dword [esp + 0x2c]
push ecx
call fcn.004699ce
add esp, 4
jmp 0x42c323
mov eax, dword [esp + 0x14]
push ebp
push ebp
lea edx, [esp + 0x20]
push edx
push ebp
push ebp
push ebp
add eax, 6
mov dword [esp + 0x30], ebp
mov ebp, dword [sym.imp.CRYPT32.dll_CryptStringToBinaryA]
push eax
call ebp
test eax, eax
jne 0x42c07f
call dword [sym.imp.KERNEL32.dll_GetLastError]
push eax
push str.Error_retrieving_memory_size_for_blob__0x_X__n
push 0x3ff
push 0x584090
call fcn.00469c7b
push 0x584090
call fcn.0041a5a0
mov ecx, dword [esp + 0x28]
push ecx
call fcn.004690f0
add esp, 0x18
jmp 0x42c31a
mov edx, dword [esp + 0x18]
push edx
call fcn.004691cd
mov esi, eax
add esp, 4
test esi, esi
jne 0x42c0c7
mov eax, dword [esp + 0x18]
push eax
push str.Error_allocating_0x_X_bytes_for_blob_n
push 0x3ff
push 0x584090
call fcn.00469c7b
push 0x584090
call fcn.0041a5a0
mov ecx, dword [esp + 0x28]
push ecx
call fcn.004690f0
add esp, 0x18
jmp 0x42c31a
mov eax, dword [esp + 0x14]
push 0
push 0
lea edx, [esp + 0x20]
push edx
push esi
push 0
push 0
add eax, 6
push eax
call ebp
test eax, eax
jne 0x42c120
call dword [sym.imp.KERNEL32.dll_GetLastError]
push eax
push str.Error_converting_key_to_blob__0x_X__n
push 0x3ff
push 0x584090
call fcn.00469c7b
push 0x584090
call fcn.0041a5a0
push esi
call fcn.004690f0
mov ecx, dword [esp + 0x2c]
push ecx
call fcn.004690f0
add esp, 0x1c
jmp 0x42c31a
mov edx, dword [esp + 0x18]
mov eax, dword [edi]
lea ebp, [ebx + 0x28]
push ebp
push 0
push 0
push edx
push esi
push eax
call dword [sym.imp.ADVAPI32.dll_CryptImportKey]
test eax, eax
jne 0x42c178
call dword [sym.imp.KERNEL32.dll_GetLastError]
push eax
push str.Error_importing_blob__0x_X__n
push 0x3ff
push 0x584090
call fcn.00469c7b
push 0x584090
call fcn.0041a5a0
push esi
call fcn.004690f0
mov ecx, dword [esp + 0x2c]
push ecx
call fcn.004690f0
add esp, 0x1c
jmp 0x42c31a
push esi
call fcn.004690f0
mov edx, dword [esp + 0x18]
push edx
call fcn.004690f0
add esp, 8
cmp dword [0x584064], 0
je 0x42c1a0
mov ecx, 0x4e43d8
mov eax, 0x4e2e58
jmp 0x42c1aa
mov ecx, 0x4e43a0
mov eax, str.Choose_encrypted_doc_file
lea edx, [esp + 0x28]
push edx
push ecx
push eax
mov ecx, ebx
call fcn.0042bd50
test al, al
je 0x42c31a
lea ecx, [esp + 0x44]
call fcn.00424cc0
cmp dword [esp + 0x40], 8
mov eax, dword [esp + 0x2c]
mov byte [esp + 0x104], 1
jae 0x42c1e0
lea eax, [esp + 0x2c]
push 0
push eax
lea ecx, [esp + 0x4c]
call fcn.00424d40
lea ecx, [esp + 0x44]
call fcn.00424be0
test edx, edx
jg 0x42c20a
jl 0x42c309
cmp eax, 0x84
jb 0x42c309
push 0
push 0x80
lea eax, [esp + 0x80]
push eax
lea ecx, [esp + 0x50]
call fcn.00424be0
sub eax, 0x84
sbb edx, 0
push edx
push eax
lea ecx, [esp + 0x58]
call fcn.00424750
mov eax, dword [ebp]
mov esi, dword [sym.imp.ADVAPI32.dll_CryptDecrypt]
lea ecx, [esp + 0x20]
push ecx
lea edx, [esp + 0x7c]
push edx
push 0
push 1
push 0
push eax
mov dword [esp + 0x38], 0x80
call esi
test eax, eax
jne 0x42c26f
push str.Error_decrypting_session_key_of_test_file_n
call fcn.0041a700
add esp, 4
jmp 0x42c309
mov edx, dword [esp + 0x20]
lea ecx, [esp + 0x24]
push ecx
mov ecx, dword [edi]
push 0
push 0
push edx
lea eax, [esp + 0x88]
push eax
push ecx
call dword [sym.imp.ADVAPI32.dll_CryptImportKey]
test eax, eax
jne 0x42c2a1
push str.Error_importing_session_key_n
call fcn.0041a700
add esp, 4
jmp 0x42c309
push 0
push 0x10
lea edx, [esp + 0x70]
push edx
push 0
push 0
lea ecx, [esp + 0x58]
call fcn.00424750
mov edx, dword [esp + 0x24]
lea eax, [esp + 0x1c]
push eax
lea ecx, [esp + 0x6c]
push ecx
push 0
push 0
push 0
push edx
mov dword [esp + 0x34], 0x10
call esi
test eax, eax
jne 0x42c2e9
push str.Error_decrypting_header_of_test_file_n
call fcn.0041a700
add esp, 4
jmp 0x42c309
mov eax, dword [esp + 0x24]
push eax
call dword [sym.imp.ADVAPI32.dll_CryptDestroyKey]
mov ecx, dword [esp + 0x1c]
push ecx
lea edx, [esp + 0x6c]
push edx
call fcn.0041a7a0
add esp, 8
mov byte [ebx + 0x20], al
lea ecx, [esp + 0x44]
mov byte [esp + 0x104], 0
call fcn.00424ce0
lea ecx, [esp + 0x28]
call fcn.0041b5b0
mov ecx, dword [esp + 0xfc]
mov dword fs:[0], ecx
pop ecx
pop edi
pop esi
pop ebp
pop ebx
mov ecx, dword [esp + 0xe4]
xor ecx, esp
call fcn.004690b5
add esp, 0xf4
ret