The documentation implies that ReadKey does not work on Windows, but it does. However, in the spirit of TMTOWTDI:

use Win32::Console;

$CONSOLE = new Win32::Console (STD_INPUT_HANDLE);

print "Enter password: ";                       # prompt

$old_mode = $CONSOLE->Mode();                   # get current mode
$new_mode = $old_mode ^ ENABLE_ECHO_INPUT;      # unset echo
$CONSOLE->Mode($new_mode);
$new_mode = undef;                              # loose the new_mode

chomp($passwd=<STDIN>);                         # read password
$CONSOLE->Mode($old_mode);                      # reset console
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Incidently, notice that chomp is safer than chop.