You can simply extract information about the SSL certificate of HTTP connections using OpenSSL

openssl s_client -connect ${URL}:${PORT}

For example:

openssl s_client -connect checkout.google.com:443

From there, it is only redirecting the output to a file or extracting information out of the stream with Perl.

require 'openssl'
require 'digest/sha1'
c = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
c.encrypt
# your pass is what is used to encrypt/decrypt
c.key = key = Digest::SHA1.hexdigest("yourpass")
c.iv = iv = c.random_iv
e = c.update("crypt this")
e << c.final
puts "encrypted: #{e}\n"
c = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
c.decrypt
c.key = key
c.iv = iv
d = c.update(e)
d << c.final
puts "decrypted: #{d}\n"

provided by menik from #rubyonrails

Works on OS X, Linux, anywhere with OpenSSL installed:

To encrypt a file:

openssl des3 -salt -in infile.txt -out encryptedfile.txt

To decrypt the file:

openssl des3 -d -salt -in encryptedfile.txt -out normalfile.txt

Do not specify the same file as input and output on encryption.. I have noticed weird effects on OS X (it eats the file). Remove the -in * stuff if you want to pipe data into it (e.g. a tarred folder). Omit the -out * stuff if you want it to pipe data out on STDOUT.