* Support NIST curve P256
This change adds support for NIST curve P256. When you use `nebula-cert ca`
or `nebula-cert keygen`, you can specify `-curve P256` to enable it. The
curve to use is based on the curve defined in your CA certificate.
Internally, we use ECDSA P256 to sign certificates, and ECDH P256 to do
Noise handshakes. P256 is not supported natively in Noise Protocol, so
we define `DHP256` in the `noiseutil` package to implement support for
it.
You cannot have a mixed network of Curve25519 and P256 certificates,
since the Noise protocol will only attempt to parse using the Curve
defined in the host's certificate.
* verify the curves match in VerifyPrivateKey
This would have failed anyways once we tried to actually use the bytes
in the private key, but its better to detect the issue up front with
a better error message.
* add cert.Curve argument to Sign method
* fix mismerge
* use crypto/ecdh
This is the preferred method for doing ECDH functions now, and also has
a boringcrypto specific codepath.
* remove other ecdh uses of crypto/elliptic
use crypto/ecdh instead
Fixes#8.
`nebula-cert ca` now supports encrypting the CA's private key with a
passphrase. Pass `-encrypt` in order to be prompted for a passphrase.
Encryption is performed using AES-256-GCM and Argon2id for KDF. KDF
parameters default to RFC recommendations, but can be overridden via CLI
flags `-argon-memory`, `-argon-parallelism`, and `-argon-iterations`.
As suggested in https://pkg.go.dev/golang.org/x/crypto/curve25519#ScalarBaseMult,
use X25519 instead of ScalarBaseMult. When using Basepoint, it may employ
some precomputed values, enhancing performance.
Co-authored-by: Wade Simmons <wade@wades.im>
Co-authored-by: Wade Simmons <wadey@slack-corp.com>
`func (nc *NebulaCertificate) VerifyPrivateKey(key []byte) error` would
previously return an error even if passed the correct private key for a
CA certificate `nc`.
That function has been updated to support CA certificates, and
nebula-cert now calls it before signing a new certificate. Previously,
it would perform all constraint checks against the CA certificate
provided, take a SHA256 fingerprint of the provided certificate, insert
it into the new node certificate, and then finally sign it with the
mismatching private key provided.
Nate Brown