I've been using the value of key MachineGuid
from HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography
to uniquely identify hosts, but from 32-bit processes running on 64-bit computers, the value appears to be missing. I guess it's searching under Wow6432Node, where it is indeed missing. According to this you should be able to get to the right key by adding a flag, but below code still doesn't appear to do the job. What am I missing?
const
KEY_WOW64_64KEY=$0100;
var
r:HKEY;
s:string;
i,l:integer;
begin
//use cryptography machineguid, keep a local copy of this in initialization?
l:=40;
if RegOpenKeyEx(HKEY_LOCAL_MACHINE,PChar('Software\Microsoft\Cryptography'),
0,KEY_QUERY_VALUE,r)=ERROR_SUCCESS then
begin
SetLength(s,l);
if RegQueryValue(r,'MachineGuid',PChar(s),l)=ERROR_SUCCESS then
begin
SetLength(s,l);
RegCloseKey(r);
end
else
begin
//try from-32-to-64
RegCloseKey(r);
if RegOpenKeyEx(HKEY_LOCAL_MACHINE,PChar('Software\Microsoft\Cryptography'),
0,KEY_QUERY_VALUE or KEY_WOW64_64KEY,r)=ERROR_SUCCESS then
begin
l:=40;
if RegQueryValue(r,'MachineGuid',PChar(s),l)=ERROR_SUCCESS then
SetLength(s,l)
else
l:=0;
RegCloseKey(r);
end;
end;
end;
Press SHIFT+F4 on your keyboard and select the components of the 64-bit registry values. Right-click one of them and select the "Properties" menu. In the "Edit Component Properties" dialog set the Condition field to VersionNT64. Tick the option 64-bit Component.
In Registry Editor, locate and click the registry key or subkey that you want to back up. Select File > Export. In the Export Registry File dialog box, select the location to which you want to save the backup copy, and then type a name for the backup file in the File name field. Select Save.
Difference between 32-bit and 64-bit OS. A 64-bit processor is more capable than a 32-bit processor because it can handle more data at once. A 64-bit processor can store more computational values, including memory addresses, which means it can access over 4 billion times the physical memory of a 32-bit processor.
Call reg.exe using this path C:\Windows\sysnative\reg.exe For example:
C:\Windows\sysnative\reg.exe QUERY "HKLM\SOFTWARE\JavaSoft\JDK" /v CurrentVersion
source: https://stackoverflow.com/a/25103599
I would suggest you use the IsWow64Process()
function to know when you are a 32-process running on a 64-bit OS, and then only apply the KEY_WOW64_64KEY
flags in that specific condition. If the app is a 32-bit process on a 32-bit OS, or a 64-bit process on a 64-bit OS, the flags is not needed.
For example:
const
KEY_WOW64_64KEY = $0100;
var
key: HKEY;
str: string;
len: DWORD;
flag: REGSAM;
wow64: BOOL;
begin
flag := 0;
wow64 := 0;
IsWow64Process(GetCurrentProcess(), @wow64);
if wow64 <> 0 then flag := KEY_WOW64_64KEY;
if RegOpenKeyEx(HKEY_LOCAL_MACHINE, 'Software\Microsoft\Cryptography', 0, KEY_QUERY_VALUE or flag, key) = ERROR_SUCCESS then
try
SetLength(str, 40);
len := Length(str) * SizeOf(Char);
if RegQueryValueEx(key, 'MachineGuid', nil, nil, PByte(Pointer(s)), @len) <> ERROR_SUCCESS then len := 0;
SetLength(str, len div SizeOf(Char));
finally
RegCloseKey(key);
end;
end;
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