Is there a easy understand example code how to implement ECDH on bls g1 ?

[张沈鹏]

I am an application programmer, not very familiar with encryption algorithms. I want to negotiate the key based on ECDH, but I don't know how to implement it based on BLS.

Is there a easy understand example code how to implement ECDH on bls g1 ?

just like this https://github.com/andreacorbellini/ecc/blob/master/scripts/ecdhe.py

# Alice generates her own keypair.
alice_private_key, alice_public_key = make_keypair()
print("Alice's private key:", hex(alice_private_key))
print("Alice's public key: (0x{:x}, 0x{:x})".format(*alice_public_key))

# Bob generates his own key pair.
bob_private_key, bob_public_key = make_keypair()
print("Bob's private key:", hex(bob_private_key))
print("Bob's public key: (0x{:x}, 0x{:x})".format(*bob_public_key))

# Alice and Bob exchange their public keys and calculate the shared secret.
s1 = scalar_mult(alice_private_key, bob_public_key)
s2 = scalar_mult(bob_private_key, alice_public_key)
assert s1 == s2

print('Shared secret: (0x{:x}, 0x{:x})'.format(*s1))

[Julian Meyer]

package main

import (
	"crypto/rand"
	"fmt"

	"github.com/phoreproject/bls"
)

func main() {
	alicePrivateKey, err := bls.RandFR(rand.Reader)
	if err != nil {
		panic(err)
	}

	alicePublicKey := bls.G1AffineOne.MulFR(alicePrivateKey.ToRepr())

	bobPrivateKey, err := bls.RandFR(rand.Reader)
	if err != nil {
		panic(err)
	}

	bobPublicKey := bls.G1AffineOne.MulFR(bobPrivateKey.ToRepr())

	s1 := bobPublicKey.MulFR(alicePrivateKey.ToRepr()).ToAffine()

	s2 := alicePublicKey.MulFR(bobPrivateKey.ToRepr()).ToAffine()

	if !s1.Equals(s2) {
		panic("shared secret should be the same")
	}

	fmt.Printf("shared secret: %s\n", s1)
}

I think that should work, but you should compare it with other implementations and probably not use it in production.

[张沈鹏]

thanks