need help encrypting micro sd card for custom use

[flyhigh@night]

I have never encrypted any type of sd card before, but it seems trivial.
The scenario complexes this process. I have a DROID I by motorola (Android OS 2.2.3)
I want at least the data on the micro sd card to be encrypted and accessible
via DROID and a computer with linux. I believe there's third party software
you can use for this. I know with motorola it is possible to encrypt the
entire filesystem and sd card without any third party software if Android OS
=> 3. However, I do not know how to speical upgrade past 2.2.3.

micro sd card is high capacity
I would prefer not to need extra software to do this. This seems like a
good security solution. I don't know much about android in general though. Your
thoughtful solutions are thanked.

[Geek-9pm]

I have never encrypted any type of sd card before, but it seems trivial.
...I have a DROID I by motorola (Android OS 2.2.3)
I want at least the data on the micro sd card to be encrypted and accessible
via DROID and a computer with linux. I..I do not know how to speical upgrade past 2.2.3.
... I don't know much about android in general though. Your
thoughtful solutions are thanked.

To read the date, you need to important items.
1.The password or keyword or phrase that resents the encryption string.
2. The algorithm use for the encryption.

If the second item is not published, you are in the dark, even when you know the first item. The whole purpose of encryption is to not make it too easy for others to get your data.
Would l you consider alternative solutions? In view of you limited knowledge of Android, that might be a more fruitful  use of you time.

[flyhigh@night]

Well that may be true it doesn't really answer my question. I want I really need to know is a simple (or just not time complex) method of installing an android OS past 2.3.3 or 3rd party software (preferrably that is already on a linux system as well).