Sophos SafeGuard Disk Encryption 4.60
Windows 2000 Professional SP4, Windows XP SP3
What does "significantly differ from the old password" mean?
In the Sophos SafeGuard Disk Encryption manual, you can find the hint that a new password will be rejected if it is "significantly similar" to the old password or username.
"Significantly" is defined as a difference of at least 20%.
The following example shows how this is calculated:
The old password is 770505Xz. This should be changed to 770808Xz. The new password is rejected by Sophos SafeGuard Disk Encryption.
Sophos SafeGuard Disk Encryption does not count the digits that have to be changed but the digits that are allowed to stay the same. In this example, 6.4 digits may remain unchanged.
SDE discards the positions after the decimal point. This means that 6 digits may remain unchanged.
At this step, Sophos SafeGuard Disk Encryption has a slight imprecision:
For the example mentioned above, the system rejects a new password if >= 6 digits remain the same (instead of > 6 digits).