Let's suppose that two entities, A and B, are establishing a secure channel and then require a mutual authentication.

A has only a RSA key pair and B has an ECDSA key pair. Both of them trust the public key of each other.

Do you feel comfortable with having A signing it's message with RSA and B signing its message with ECDSA ?

They do have an equivalent key length for both key pairs (keylength.com)

  • $\begingroup$ What research have you done? Is this homework? $\endgroup$ – axapaxa Mar 8 '17 at 16:54
  • $\begingroup$ It is a question I am asking to myself but don't find why this can be problematic ? I've googled this and didn't find anything related to. $\endgroup$ – FdLSifu Mar 8 '17 at 16:58

Yes, given the following conditions:

  1. A trusts the public key of B belonging to B
  2. B trusts the public key of A belonging to A
  3. A trusts the signing algorithm ECDSA used by B
  4. B trusts the signing algorithm RSA used by A
  5. A trusts the key length of B
  6. B trusts the key length of A

Normally, the condition 3,4 use the same algorithm, but if both A and B put trust in the other's algorithm then there is no reason not to trust the authenticity.

As you said 1,2 and 5,6 are true.


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