Faster way to use RSA...

From: Beta-Ray Bill (nSePtAnMeSwUsC@KaSttbi.com)
Date: 03/30/03 

From: "Beta-Ray Bill" <nSePtAnMeSwUsC@KaSttbi.com>
Date: Sun, 30 Mar 2003 21:22:43 GMT

Ease of attack for RSA is based on not being able to factor N (N = PxQ) due
to N being known to all (e.g. (e,N) is my private key and (d,N) being my
public
key).
As computers get faster RSA users must select P and Q values that are larger
to remain safe(r).

My questions are as follows:

1. If N could be kept secret (e.g. just between the people who communicate)
    then would RSA key sizes stop increasing?

2. Can cryptoanalysis determine the value of N from analysis of the
    ciphertext without knowledge of the public key, which of course contains
N?

3. Would using RSA with smaller P and Q values (i.e. smaller N) to encrypt a
    message be easier to attack compared to a message encrypted using larger
P and
    Q values IF AND ONLY IF the value of smaller N could be kept secret?

4. Doesn't large N values drive up the time to encrypt/decrypt a message?

Why doesn't someone select smaller P and Q values, which result in faster
encryption, and generate e and d. Encrypt a message using smaller P and Q, e
and d. Bob
could use RSA in the standard way (e.g. with large P, Q and large N) to send
smaller P and Q, e
and d to Alice. Bob would also send the encrypted message as well. Alice
would reverse the
process. Wouldn't the attacker then have to brute force pick smaller P and Q
pairs
and for each further test multiple e and d pairs to find solutions?

After all, RSA is a very clever way to reconstruct a value from knowing its
remainder and the decryption key - of course.

I didn't see this in the FAQ.

Thanks in advance...

Bill

Relevant Pages

  • Re: Asp.net 2.0 deployment with encryption
    ... I guesss I will create a rsa key on the production server. ... Export the public xml/key to a common location on some server. ... As for the ASP.NET 2.0 configuration section protection, ... encryption which use a single shared session key to encrypt and decrypte ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: What is exponent?
    ... For simple description of RSA algorithm ... I also have the receiver's certificate (public key only). ... Use RSA to encrypt the session key ...
    (microsoft.public.dotnet.security)
  • Re: Decrypt RSA using D
    ... We are planning on using RSA with WSE, so it only uses RSA to encrypt the symmetric key used for the SOAP body--the same scenario you outlined below. ... owner of the private key can decrypt it. ... always embedded inside the CSP key container and never passed out into the ...
    (microsoft.public.dotnet.framework)
  • Re: Java, MSCAPI interoperability - newbie
    ... A good solution (analogous to enveloped email) is to have the two parties have ... Then you can leverage RSA key-exchange protocol very easily. ... data with random symmetric key and encrypt the symmetric key with their local private RSA key ...
    (microsoft.public.platformsdk.security)
  • Re: asymmetric encryption options
    ... now I am generating a random key, encrypting the data with it using ... then encrypting the key with rsa. ... You can split the longer key into blocks, and encrypt them alone. ... The original padding is really simple to implement, ...
    (comp.lang.ruby)