[Tutor] looking for volunteers with testing simple python program

[Walter Prins]

Hi Alexander


On 23 June 2013 22:46, Alexander <rhettnaxel at gmail.com> wrote:

> I guess this is for testing, but I have a question. If somebody sends you
> their .pub file (email or otherwise over internet), and a villainous third
> party intercepts that .pub file, will they be able to decrypt the data sent
> over this program?


While I've not looked at the actual program, it appears to use standard
public key encryption techniques.  The way public key encryption works is
essentially that entities always have a public and a private key.  The
public keys are always published and freely available, and are used to
*encrypt* messages for given individuals.  Keys are essentially one-way,
which means you cannot de-crypt a message encrypted with the same key it
was encrypted with.  Instead, only the received with the corresponding
private key can decrypt the encrypted message.

Hence, to answer you question:  If a villainous third party intercepts the
pub key, that doesn't help them in decrypting messages encrypted with that
key.  At best, they can also send you encrypted messages. If they wanted to
decrypt messages meant for you they'd have to somehow gain access to your
private key.

Regards

Walter
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