From: Eleanor McHugh <eleanor@...>
Date: 2009-05-04T00:50:33+09:00
Subject: Re: OpenSSL::Cipher dad decrypt

On 3 May 2009, at 14:44, Pål Bergström wrote:
> This is what I use. Would be good if I could catch the error and  
> prevent
> it from "hanging" the browser with an error (using Rails).

>  def self.decrypt(cstring)
>    cgi = CGI.new("html3")
>    passo = cgi.cookies["thecookie"].to_s
>    etext = Base64.decode64(cstring)
>    c = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
>    c.decrypt
>    c.key = key = Digest::SHA2.digest(passo)
>    d = c.update(etext)
>    d << c.final
>    return d
>  end


You need to do something along the lines of:

   begin
     c = OpenSSL::Cipher::Cipher.new("aes-256-cbc")
     c.decrypt
     c.key = key = Digest::SHA2.digest(passo)
     d = c.update(etext)
     d << c.final
     d
   rescue OpenSSL::CipherError => e
     "incorrect password"
   rescue Exception => e
     "unknown error"
   end

where you can have several rescue blocks, one for each exception  
recovery behaviour you have a use for.


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason