Originally Posted by zaoka
Is it possible to decrypt hard drive and than clone it, extend partition and encrypt again..??
That's most likely to be the best option.
For the actual copy process after the de-crypt you could go with dd and enlarge the partitions to your needs (fdisk, resize2fs etc.) after the copy and before you re-encrypt.
Since the sizes of your drives are quite different you want to have an extra eye on block sizes etc