I recently made a 8.3 netinstall cd and went through the installation
process (with encryption). After installation was done it rebooted and
the password prompt came up. I tried entering my password several times,
failing each time, even though I am sure I entered it correctly most of
the time.
I then re-inserted the 8.3 netinstall cd and using rescue mode, I was
able to successfully enter the password and mount the drive in 'rescue
mode'. I am new to Linux so i wasn't sure how to fix it from there.
I then made a 7.9 netinstall cd and installed with encryption to test if
my hardware was at fault. This time I was able to successfully enter my
password and boot my encrypted OS.
BTW my password consisted of upper case, lower case and numbers.