From: "Iñaki Baz Castillo" <ibc@...>
Date: 2012-12-20T20:39:32+09:00
Subject: Re: Efficient way to encode a string with a secret string and recover it

Thanks, I'm trying it and will compare with crypt19 as suggested by Joel.

Thanks to both.


2012/12/20 Heesob Park <phasis@gmail.com>:
> Hi,
>
> 2012/12/20 Iñaki Baz Castillo <ibc@aliax.net>:
>> Hi, basically I receive a string generated by a user, then "encode" it
>> using some secret string I own and pass the result to other user, and
>> when I receive such a resulting string I must be able to decode it
>> using my secret string (but no other should be able to decode the
>> resulting string without knowing my secret key. This is:
>>
>>
>> original_string = "test"
>>
>> secret_key = "ABCD"
>>
>> modified_string = HASH_FUNCTION(original_string, secret_key)
>>
>> original_string = UNHASH_FUNCTION(modified_string, secret_key)
>>
>>
>> Any suggestion for the above HASH_FUNCTION and UNHASH_FUNCTION? I
>> would like it to be something really efficient.
>>
>> Thanks a lot.
>>
> You can use openssl module something like this:
>
> def encrypt(input,key)
>         require 'openssl'
>         des = OpenSSL::Cipher::Cipher.new("des-ede-cbc")
>         des.encrypt
>         des.key= "%16s" % key
>         des.update(input)+des.final
> end
>
> def decrypt(input,key)
>         require 'openssl'
>         des = OpenSSL::Cipher::Cipher.new("des-ede-cbc")
>         des.decrypt
>         des.key = "%16s" % key
>         des.update(input)+des.final
> end
>
> But, I am not sure it is really efficient.
>
> Regards,
>
> Park Heesob
>



-- 
Iñaki Baz Castillo
<ibc@aliax.net>