.NET implementation (libraries) of elliptic curve cryptography

Question

Please can you suggest any implementation of elliptical curve cryptography to be used on .NET platform?

Also if you have used them, can you tell me the recommended curve

Answer 1

The way you usually use ECC for encryption is by using "Ephemeral-Static Diffie-Hellman".

It works this way:

• Take the intended receivers public key (perhaps from a certificate). This is the static key.
• Generate a temporary ECDH keypair. This is the ephemeral keypair.
• Use the keys to generate a shared symmetric key.
• Encrypt the data with the symmetric key.
• Transmit the encrypted data together with the public key from the ephemeral keypair.

The receiver can now use the ephemeral public key and his own static private key to recreate the symmetric key and decrypt the data.

You can read more in Standards for Efficient Cryptography: SEC 1: Elliptic Curve Cryptography section 5.1.3.