In this forum thread,
How not to mount Encrypted partition? - openSUSE Forums,
I asked if there was a way to not mount an encrypted partition.
I found the answer and wanted to share it.
Encrypted partitions use a different file other than /etc/fstab.
If you comment a mount point in /etc/fstab it will not get mounted, but it’s password will still be prompted.
The file to edit for encrypted partitions is
/etc/crypttab.
Just like /etc/fstab, /etc/crypttab has an option to not mount automatically a partition so one can have:
cr_sdb5 /dev/disk/by-id/scsi-SATA_SAMSUNG_HD501LJS0MUJDWPC42370-part5 none noauto
That will prevent the partition from getting the password to be asked OR to have it mounted. The noauto option in /etc/fstab seems to be ignored for encrypted filesystems.
I also discovered that if for any reason you fail to put your password in time or type in the wrong password to try to mount an encrypted partition by itself you can do:
service boot.crypto start <entry from cryptab>
Hope this helps someone in the future.
[Edit]. To make more concise and correct a few minor errors.