[dev-crypto-csharp] ECDH ECDSA

[Jan Hammer]

Hi!

 

Im exchanging keys between BouncyCastle C# and the Cryptovision C API,

however I have some compatibility problems doing so:

 

1.:

Cryptovision derives the key the following way, from the other partys public key and the own private key (the number of derivations can be chosen):

 **  This function calculates the common secret d1 * Q2 (= d1 * d2 * G)
 **  and derives the output key from the x-coordinate of the secret with
 **  the KDF2HMACSHA1 derivation function of the library.

 

Using AgreementUtilities.GetBasicAgreement("ECDH") and => CalculateAgreement() obviously leads to a different result.

How does the CalculateAgreement function calculate the output and therefore is there a way to come to the same conclusion as on the Cryptovision part?

 

 

2.:

Cryptovision computes the ECDSA signature according to ANSI X9.62, the parameters im getting are the  signature_r and signature_s components.

In BouncyCastle im using SignerUtilities.GetSigner("ECDSA") to compute and verify the signatures.

So now I have the byte[] signature on the BouncyCastle side and the r and s components of the signature on the Cryptovision side,

any information what the byte[] computed in BouncyCastle consists of (r/s, r+s components..?) or how these things can be put together?

 

Any information will be highly appreciated!

 

Thanks in advance and regards,

Jan Hammer