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Diffie Hellman JavaScript
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| const BN = require('bn.js'); | |
| var USE_BINARY = true; | |
| var UNIQUE_PRIME = true; | |
| var MIN_INTEGER = 100; | |
| var MAX_INTEGER = 40000; //Number.MAX_SAFE_INTEGER; | |
| // https://jsperf.com/prime-numbers/7 | |
| function number(p) { | |
| return USE_BINARY ? | |
| new BN(p, 16) : | |
| parseInt(p, 16) | |
| } | |
| function pow(a, b) { | |
| process.stdout.write('+'); | |
| return USE_BINARY ? | |
| a.pow(b) : | |
| Math.pow(a, b).toFixed(3); | |
| } | |
| function mod(a, b) { | |
| process.stdout.write('+'); | |
| return USE_BINARY ? | |
| a.mod(b) : | |
| (a % b).toFixed(3); | |
| } | |
| function equal(a, b) { | |
| return USE_BINARY ? | |
| a.cmp(b) === 0 : | |
| a === b; | |
| } | |
| function getRandomInt(min, max) { | |
| min = min || 2; | |
| max = max || Number.MAX_SAFE_INTEGER; | |
| return Math.floor(Math.random() * (max - min + 1)) + min; | |
| } | |
| function getRandomPrime(min, max) { | |
| var p; | |
| do { | |
| //process.stdout.write('.'); | |
| p = getRandomInt(min, max); | |
| } while( | |
| isPrime(p) === false || ( | |
| UNIQUE_PRIME && | |
| getRandomPrime.cache.hasOwnProperty(p) | |
| ) | |
| ); | |
| process.stdout.write('*'); | |
| getRandomPrime.cache[p] = true; | |
| return number(p); | |
| } | |
| getRandomPrime.cache = {}; | |
| function isPrime(num) { | |
| if (isPrime.cache.hasOwnProperty(num)) { | |
| return isPrime.cache[num]; | |
| } | |
| // Everything but 1 can be prime | |
| var prime = num !== 1; | |
| for (var i = 2; i < num; i++) { | |
| if (num % i === 0) { | |
| prime = false; | |
| break; | |
| } | |
| } | |
| isPrime.cache[num] = prime; | |
| return prime; | |
| }; | |
| isPrime.cache = {}; | |
| function makeKeyPair(min, max) { | |
| function createPublicKey(max) { | |
| return getRandomPrime(min, max - 1) | |
| } | |
| // Setup Alice | |
| var alice = { | |
| publicKey: null, | |
| privateKey: null | |
| }; | |
| var p = createPublicKey(max); | |
| var a = getRandomPrime(min, p); // < (p - 1) | |
| alice.publicKey = p; | |
| alice.privateKey = a; | |
| // Setup Bob | |
| var bob = { | |
| publicKey: null, | |
| privateKey: null | |
| }; | |
| var g = createPublicKey(max); | |
| var b = getRandomPrime(min, g); // < (g - 1) | |
| bob.publicKey = g; | |
| bob.privateKey = b; | |
| // Bob send g to Alice | |
| alice.remotePublicKey = g; | |
| // Alice forge A based g | |
| var A = mod(pow(g, a), p); | |
| // Alice share A to Bob | |
| bob.publicToken = A; | |
| // Alice send A and p | |
| bob.remotePublicKey = p; | |
| // Alice forge B based p | |
| var B = mod(pow(g, b), p); | |
| // Alice share B to Alice | |
| alice.publicToken = B; | |
| // Bob then forge aSecret based on A, b and p | |
| var bSecret = mod(pow(A, b), p); | |
| bob.sharedSecret = bSecret; | |
| // Alice then forge aSecret based on B, a and p | |
| var aSecret = mod(pow(B, a), p); | |
| alice.sharedSecret = aSecret; | |
| // Alice and Bob share the same token. | |
| var isValid = equal(aSecret, bSecret); | |
| return { | |
| alice: alice, | |
| bob: bob, | |
| result: isValid | |
| }; | |
| } | |
| do { | |
| var pair = makeKeyPair(MIN_INTEGER, MAX_INTEGER) | |
| if (pair.result === false) { | |
| console.log('FAILED', pair); | |
| break; | |
| } else { | |
| process.stdout.write('_'); | |
| } | |
| } while(1); | |
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