Re: Public - Private key

Thanks for the reply.

I understand that these keys have large length hence these are difficult to
crack. Can you give me a simple example regarding 1.

As to what could be a very small private key and veyr small public key so
that I can see
- some data getting encrypted by public key
- the data can not be decrypted using public key
- the data can only be decrypted using private key

Thanks,
Tim

"jwgoerlich@xxxxxxxxx" wrote:

The short answer to (1) is that asymmetric encryption requires one key
to encrypt and a different key to decrypt. Mathematically, P1 can only
decrypt A1 and likewise A1 can only decrypt P1.

The answer to (2) is that a utility which derives a private key from a
given public key would of course break the system, because then
anything could be decrypted. Crypto systems are designed to resist
such attacks. There may be ways to do it (reaction attacks against
known plain text comes to mind) but they are not much of a risk.

Regards,

J Wolfgang Goerlich

On Jun 28, 11:46 am, amsical <amsi...@xxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
Hi,

If PC1 has public key P1 and private key A1

and

PC2 has public key P2 and private key A2

When PC1 communicates securely with PC2, PC1 will encrypt the data using the
key P2, which can be decrypted ONLY by using private key A2.

My question is,
1. If data has been encrypted using P2 why it can't be decrypted using the
same key?

2. SN.exe generates pair of public and private keys, why can't a utility be
written which will generate a Private key for a given Public key?

Thanks,
Tim



.

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