From: snacktime <snacktime@...>
Date: 2006-08-31T07:48:53+09:00
Subject: Re: encryption library

Here is an example of one way to use public key (asymmetric)
encryption using openssl.  Requires an ssl certificate/key pair, but
only the certificate is required to encrypt.

require 'openssl'

keyfile = 'test.key'
certfile = 'test.crt'
data = "this is a test"

cert = OpenSSL::X509::Certificate.new(File.read(certfile))
key = OpenSSL::PKey::RSA.new(File.read(keyfile))
cipher = OpenSSL::Cipher::AES.new("128-CBC")

tmp = OpenSSL::PKCS7.encrypt([cert], data, cipher, OpenSSL::PKCS7::BINARY)
p7 = OpenSSL::PKCS7::PKCS7.new(tmp.to_der)

## Data will be stored as string so emulate that here
p7s = p7.to_s

## Create pkcs7 object out of pkcs7 data
p7 = OpenSSL::PKCS7::PKCS7.new(p7s)
dec = p7.decrypt(key,cert)
print dec