How do I secure my Exchange key?

How do I secure my Exchange key?

The standard approach to secure communication involves two steps. First, the two conversing parties A and B securely establish a session key, and second, they use the key to encrypt and authenticate the exchanged messages.

How do we distribute symmetric keys?

Key distribution

1. In symmetric key cryptography, both parties must possess a secret key which they must exchange prior to using any encryption.
2. In public key cryptography, the key distribution of public keys is done through public key servers.

Does symmetric encryption provide non repudiation?

So do symmetric keys have non-repudiation or not? It makes sense that they can not be used for signatures and non-repudiation since symmetric keys are the same and thus the system can’t distinguish which one belongs to which person and which one is first etc.

What advantages do asymmetric algorithms have over symmetric ones?

What advantages do asymmetric algorithms have over symmetric ones? they allow secure communication over insecure channels; By exchanging public keys for encrypting data, asymmetric encryption securely exchanges information over untrusted channels.

Can you send information over an unsecure channel?

You can’t. To securely send information over an unsecure channel, you need encryption. Symmetric encryption is out, because you would first need to transport the key, which you can’t do securely over an unsecure channel [*]. That leaves you with public key cryptography.

Why is key exchange necessary at all in RSA?

Symmetric encryption is not limited in any way. Further, asymmetric encryption is slow. If you just use RSA to exchange a symmetric key, a la plain TLS, then you have no Perfect Forward Secrecy – anyone gaining access to either private key can decrypt the symmetric key and therefore all content.

How to authenticate a user over an insecure connection?

There is actually a way to authenticate a user over an insecure connection: Secure Remote Password (SRP) protocol.

Why is DH key exchange necessary at all?

DH key exchange makes it possible to create a key independent from the certificate. This way knowledge of the certificate alone is not enough to decode previously captured data. This is called forward secrecy. See Wikipediafor more information.