On Tue, Dec 29, 2009 at 6:24 AM, Vamsi Krishna <li...@ruby-forum.com> wrote: > Hi All, > > I wanted to ensure confidentiality by encrypting some information. I > also wanted to maintain non-reputability by encrypting huge data with > the senders > private RSA key. > > Here the data is first encrypted with Senders(lets say A) > private key and then Recievers(lets say B) public key.To decrypt, 'B' is > the only one who can decrypt the data, and he knows the data came from > 'A' because A's public RSA key is also needed. > > The following is the code: > > require 'openssl' > > reciever_public_key_file = 'reciever_public.pem' > sender_public_key_file = 'sender_public.pem' > > sender = OpenSSL::PKey::RSA.new(File.read(sender_public_key_file)) > > sender_public_key = sender.public_key > > reciever = OpenSSL::PKey::RSA.new(File.read(reciever_public_key_file)) > reciever_pub_key = reciever.public_key > > password="vamsikrishna" > sender_private_key = > penSSL::PKey::RSA.new(File.read(private_key_file),password) > > string = "Simple encryption example message hope some one may help, lets > hope for better." > #[Here the string may be huge data like a file also, for that i changed > the below line to first_encrypted = > sender.private_encrypt(File.read(string)) ] > > first_encrypted = sender_private_key.private_encrypt(string) > second_encrypted = reciever.public_encrypt(first_encrypted) > > first_decrypted = reciever.private_decrypt(second_encrypted) > second_decrypted = sender.public_decrypt(first_decrypted) > > puts second_decrypted > > > But it throws an error: > public_encrypt': data too large for key size (OpenSSL::PKey::RSAError) > > > Don't 've any idea right now to overcome this.And let me know where i'm > going wrong.
Excuse me for being blunt but, clearly you have no idea what you're doing regarding crypto, so unless you like introducing major security vulnerabilities by miss-using RSA, AES, etc I can not recommend strongly enough you stop what you're doing and follow two simple rules: 1) Use TLSv1 for secure network communication between hosts 2) Use PGP for securely encrypting files People like to think "I used <insert name of well known encryption algorithm here> so I'm secure now" without understanding how easy it is to screw up. And no, reading a book like Applied Cryptography doesn't magically make you a crypto expert who can now avoid these mistakes. RSA especially is easy to use incorrectly and reduce its security to virtually nil. -- Aaron Turner http://synfin.net/ http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. -- Benjamin Franklin "carpe diem quam minimum credula postero" -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-t...@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
