Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>So it seems to me that you have 2 main requirements that you are attempting to use <code>deterministic RSA</code> to solve:</p> <ol> <li>Allowing voters to ensure the integrity of their vote</li> <li>Allowing auditors to ensure the integrity of all votes</li> </ol> <p><a href="http://en.wikipedia.org/wiki/Digital_signature" rel="nofollow">Digital Signatures</a> should solve this problem. You can take your ciphertext from column 1, hash it, and encrypt the hash with a <strong>private</strong> key. That encrypted hash can then be placed in column 2. To verify the integrity of column 1, simply use the corresponding public key to decrypt the hash in column 2, hash column 1, and compare those 2 values. If they are equal, the data has not been tampered with. Only parties that have the private key could possibly tamper with the data in these columns, because only they can make a matching pair. This is similar to an HMAC, but has the advantage of using public/private keys rather than a secret shared key. Thus anybody can verify, but only trusted parties can modify.</p> <p>One thing to note about deterministic schema is that it will leak information in many ways. Let's assume that I know I voted for <code>Blue</code> as my favorite color. I can see that the resulting ciphertext of my vote is 0x12345678. If the schema is completely deterministic, I know that anybody else that has a corresponding ciphertext of 0x12345678 also voted for <code>Blue</code>. Also, since you will typically have a finite set of vote choices, a <a href="http://en.wikipedia.org/wiki/Chosen-ciphertext_attack" rel="nofollow">chosen plaintext attack</a> is incredibly easy. Thus you really want to let RSA do its job and use the intended padding scheme.</p> <p>The next thing you may want to consider is protecting the system from a form of <a href="http://en.wikipedia.org/wiki/Replay_attack" rel="nofollow">Replay Attack</a> by numbering the votes or something like that. As I understand your schema, it looks like if I somehow got access to where you store your votes (or got in the middle of any communication), I could essentially spoof or spam fake votes just by replaying or copying data that I've already seen (another problem with being deterministic).</p>
    singulars
    1. This table or related slice is empty.
    1. PODeterministic RSA encryption in Java
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USLuke
    1. USLuke
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COThank you very much (everyone) for reading and for your comments. I'm not sure it is an HMAC I need - I've added some bullet points at the bottom of the question to try and clarify why it is I want the RSA encryption to be deterministic. But I may be missing something or failing to see an alternative - if you have time to take a look and/or let me know if an HMAC could still work, I'd really appreciate it. Thanks.
      singulars
      1. PO
      1. USChris
    2. COI gave it another shot. You're right, an HMAC didn't quite fit your needs, but I think Digital Signatures do. I think what you were attempting to do was close to a digital signature anyway. Most of all, I strongly urge you not to use RSA in the way that you are trying to use it. It will **not** be secure.
      singulars
      1. PO
      1. USLuke
    3. COHaving read through everyone's answers/comments I think yours (encrypting hash with private key, and distributing the public key to auditors who can use it to decrypt and verify the integrity of the hashes) might be the best solution... I haven't heard of private key encryption / public key decryption before, didn't know it was possible with RSA - will need to read up on it. Thanks very much for the idea. The chosen plaintext attack wouldn't work as the encrypted information is in fact the cyclic shift of the candidate list, which is a large number (to be encrypted) modulo N candidates.
      singulars
      1. PO
      1. USChris
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload