The Linux command aespipe is used to encrypt and decrypt on the Bash pipeline. It uses AES encryption in CBC mode. During the 29c3 CTF, one challenge required decrypting using aespipe. Being a Windows guy, I naturally turned to Cygwin. The latest aespipe supports Cygwin and installs easily enough.
$ wget http://loop-aes.sourceforge.net/aespipe/aespipe-v2.4c.tar.bz2
$ tar xvfj aespipe-v2.4c.tar.bz2
$ cd aespipe-v2.4c
$ make install