var EC = require('elliptic').ec;

// Create and initialize EC context
// (better do it once and reuse it)
var ec = new EC('secp256k1');

// Generate keys
var key = ec.genKeyPair();

// Sign the message's hash (input must be an array, or a hex-string)
var msgHash = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
var signature = key.sign(msgHash);

// Export DER encoded signature in Array
var derSign = signature.toDER();

// Verify signature
console.log(key.verify(msgHash, derSign));

// CHECK WITH NO PRIVATE KEY

var pubPoint = key.getPublic();
var x = pubPoint.getX();
var y = pubPoint.getY();

// Public Key MUST be either:
// 1) '04' + hex string of x + hex string of y; or
// 2) object with two hex string properties (x and y); or
// 3) object with two buffer properties (x and y)
var pub = pubPoint.encode('hex');                                 // case 1
var pub = { x: x.toString('hex'), y: y.toString('hex') };         // case 2
var pub = { x: x.toBuffer(), y: y.toBuffer() };                   // case 3
var pub = { x: x.toArrayLike(Buffer), y: y.toArrayLike(Buffer) }; // case 3

// Import public key
var key = ec.keyFromPublic(pub, 'hex');

// Signature MUST be either:
// 1) DER-encoded signature as hex-string; or
// 2) DER-encoded signature as buffer; or
// 3) object with two hex-string properties (r and s); or
// 4) object with two buffer properties (r and s)

var signature = '3046022100...'; // case 1
var signature = new Buffer('...'); // case 2
var signature = { r: 'b1fc...', s: '9c42...' }; // case 3

// Verify signature
console.log(key.verify(msgHash, signature));

var EdDSA = require('elliptic').eddsa;

// Create and initialize EdDSA context
// (better do it once and reuse it)
var ec = new EdDSA('ed25519');

// Create key pair from secret
var key = ec.keyFromSecret('693e3c...'); // hex string, array or Buffer

// Sign the message's hash (input must be an array, or a hex-string)
var msgHash = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
var signature = key.sign(msgHash).toHex();

// Verify signature
console.log(key.verify(msgHash, signature));

// CHECK WITH NO PRIVATE KEY

// Import public key
var pub = '0a1af638...';
var key = ec.keyFromPublic(pub, 'hex');

// Verify signature
var signature = '70bed1...';
console.log(key.verify(msgHash, signature));

var EC = require('elliptic').ec;
var ec = new EC('curve25519');

// Generate keys
var key1 = ec.genKeyPair();
var key2 = ec.genKeyPair();

var shared1 = key1.derive(key2.getPublic());
var shared2 = key2.derive(key1.getPublic());

console.log('Both shared secrets are BN instances');
console.log(shared1.toString(16));
console.log(shared2.toString(16));

var EC = require('elliptic').ec;
var ec = new EC('curve25519');

var A = ec.genKeyPair();
var B = ec.genKeyPair();
var C = ec.genKeyPair();

var AB = A.getPublic().mul(B.getPrivate())
var BC = B.getPublic().mul(C.getPrivate())
var CA = C.getPublic().mul(A.getPrivate())

var ABC = AB.mul(C.getPrivate())
var BCA = BC.mul(A.getPrivate())
var CAB = CA.mul(B.getPrivate())

console.log(ABC.getX().toString(16))
console.log(BCA.getX().toString(16))
console.log(CAB.getX().toString(16))