Shell Programming and Scripting

Hi,

I have a file which contains 4 columns. I want to encrypt only the first column. The rest of data must be as it is.
flat file:

12234333 jakdjf 394839 343874
73746373 5jdkfdj 383993 958939
83473843 lksdjfj 388383 349399

so, 1 should be replace by 4, 2 with 8, 3 with 7.....
the output should effect only first column.
Please help me.

This kinda sounds like homework - your 'cryptography' is not cryptogrphy.
If this is for a real world application, somebody is giving you bad directions, IMO.

It would probably be a good idea to take a brief moment to explain "why" and "do you know what you are doing", as usually one or the other of these two often turns out to be a problem when dealing with encryption.

You can of course encrypt anything you like, but it would help to know: do you need to be able to get it back (really!) and should it still be text-only.

Passwords are usually encrypted in such a way that they cannot be recovered -- all you can (or ever need to) do is encrypt another input string and compare; if they are the same, the user had the right password.

Should all the information be encrypted using a single passphrase, or do they need to be individual?

Have you been thinking about whether symmetric, secret-key encryption would suit your needs better, or asymmetric public-key encryption? Do you have a preference for any particular encryption algorithm or software?

hi,
Thanks all for the reply.
I don't get back to the data, but i need the output in encrypted form.
As of business logic, i need to encrypt that column.
if anyone can help, it would be really great.

Just do:
awk '{$1="secret";print}' file