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

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 开发者_如何学Gowell.

-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.

You can use openssl for this.

On most linux flavors you can use gpg.

GPG website

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