github.com/smalaichami/go-bowhead@v0.0.0-20180311002552-16302db95eaa/crypto/bn256/cloudflare/example_test.go (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build amd64,!appengine,!gccgo
     6  
     7  package bn256
     8  
     9  import (
    10  	"crypto/rand"
    11  )
    12  
    13  func ExamplePair() {
    14  	// This implements the tripartite Diffie-Hellman algorithm from "A One
    15  	// Round Protocol for Tripartite Diffie-Hellman", A. Joux.
    16  	// http://www.springerlink.com/content/cddc57yyva0hburb/fulltext.pdf
    17  
    18  	// Each of three parties, a, b and c, generate a private value.
    19  	a, _ := rand.Int(rand.Reader, Order)
    20  	b, _ := rand.Int(rand.Reader, Order)
    21  	c, _ := rand.Int(rand.Reader, Order)
    22  
    23  	// Then each party calculates g₁ and g₂ times their private value.
    24  	pa := new(G1).ScalarBaseMult(a)
    25  	qa := new(G2).ScalarBaseMult(a)
    26  
    27  	pb := new(G1).ScalarBaseMult(b)
    28  	qb := new(G2).ScalarBaseMult(b)
    29  
    30  	pc := new(G1).ScalarBaseMult(c)
    31  	qc := new(G2).ScalarBaseMult(c)
    32  
    33  	// Now each party exchanges its public values with the other two and
    34  	// all parties can calculate the shared key.
    35  	k1 := Pair(pb, qc)
    36  	k1.ScalarMult(k1, a)
    37  
    38  	k2 := Pair(pc, qa)
    39  	k2.ScalarMult(k2, b)
    40  
    41  	k3 := Pair(pa, qb)
    42  	k3.ScalarMult(k3, c)
    43  
    44  	// k1, k2 and k3 will all be equal.
    45  }