C# bouncy castle DHKdfParameters extraInfo not affect result

Asked Jul 26 '19 at 01:20

Active Jul 26 '19 at 01:29

Viewed 196 times

I use bouncy castle for using Key Derivation Function for ECDH and AES128-GCM.

So It is my code.

byte[] secretZ = txtEcdhKdfZ.Text.HexToByteArray();
byte[] extraInfo = txtEcdhKdfInfo.Text.HexToByteArray();

ECDHKekGenerator egH = new ECDHKekGenerator(DigestUtilities.GetDigest("SHA256"));

egH.Init(new DHKdfParameters(NistObjectIdentifiers.IdAes128Gcm, 128, secretZ, extraInfo));
byte[] symmetricKey = new byte[DigestUtilities.GetDigest("SHA256").GetDigestSize()];
egH.GenerateBytes(symmetricKey, 0, symmetricKey.Length);

txtEcdhKdf.Text = symmetricKey.ToHex();

I saw that code here.

But extraInfo not affect result.

Because the result is always the same whether extraInfo has a value or not.

The secretZ value and keySize in new DHKdfParameters(...) affects the result.

How can I make extraInfo affect the results?

edited Jul 26 '19 at 01:29

asked Jul 26 '19 at 01:20

NWOWN

1

Please remember to always define _how_ something isn't working. – ProgrammingLlama Jul 26 '19 at 01:21
*extraInfo* is not supposed to affect the result. It's an inert, pointless parameter. – President James K. Polk Jul 26 '19 at 11:58

C# bouncy castle DHKdfParameters extraInfo not affect result

0 Answers0