cmd line app for encryption via std in/out/error?

Question

Now that i am thinking about it, it seems unusual that i dont know. Is there an app that allows me to encypt data with std in/out/error? perhaps something like

appname -c AES -k MyTextKey (or -kh for a key made from hex data) -o stdout -i stdin

I never bothered learning how to use one outside of .NET and it would be annoying to do it for each language. Signing would be good too

appname -s salt_text -in file.blah -o key.sig

On windows but i'd like a linux solution as well.

-edit- gpg does not look like a solution. I looked but cant see how to encrypt something with cipher using a password and not use public/private keys which seem to be the only way it can encrypt.

Answer 1

On most linux flavors you can use gpg.

GPG website

Answer 2

Here's an example in .net of the GnuPG calls wrapped in managed .net code. The encryption / decryption occurs by writing / reading to the console process using streamreader / streamwriter calls.

http://www.codeproject.com/KB/security/gnupgdotnet.aspx

Answer 3

You can use openssl for this.