Added new generateDHKey and generatePrime functions

- Added my logger package.
- Moved JavaScript into new src/ dir.

bin/sneak

@@ -10,8 +10,12 @@ if ((index = argv.indexOf('-e')) > -1) {
     console.log(sneak.encode(argv[index + 1], bignum(argv[index + 2])));
 } else if ((index = argv.indexOf('-d')) > -1) {
     console.log(sneak.decode(argv[index + 1], bignum(argv[index + 2])));
+} else if ((index = argv.indexOf('generateDHKey')) > -1) {
+    console.log(sneak.generateDHKey());
 } else if ((index = argv.indexOf('generateKey')) > -1) {
     console.log(sneak.generateKey());
+} else if ((index = argv.indexOf('generatePrime')) > -1) {
+    console.log(sneak.generatePrime());
 } else {
     console.log('Unrecognized command');
 }

package.json

@@ -5,7 +5,7 @@
   "bin": {
     "sneak": "./bin/sneak"
   },
-  "main": "index.js",
+  "main": "./src/index.js",
   "keywords": [
     "xor",
     "base64",
@@ -30,7 +30,8 @@
     "test": "npm run clean && npm run lint && npm run specs"
   },
   "dependencies": {
-    "bignum": "^0.12.5"
+    "bignum": "^0.12.5",
+    "logger": "git+https://github.com/btoll/logger.git"
   }
 }
 

spec/sneak-spec.js

@@ -2,7 +2,7 @@
 'use strict';
 
 const bignum = require('bignum');
-const sneak = require('../index');
+const sneak = require('../src/index');
 
 describe('sneak', () => {
     const defaultKey = sneak.generateKey(100);

src/dh.js

@@ -0,0 +1,59 @@
+'use strict';
+
+const bignum = require('bignum');
+const logger = require('logger');
+const readline = require('readline');
+
+let getSecretIter = null;
+let textIter = null;
+
+const ask = query =>
+    rl.question(query, answer => {
+        const n = bignum(answer);
+
+        if (n) {
+            getSecretIter.next([
+                n,
+                textIter.next().value
+            ]);
+        }
+    });
+
+function* getSecret(baseQuestion) {
+    const [g, modulusQuestion] = yield ask(baseQuestion);
+    const [p, secretQuestion] = yield ask(modulusQuestion);
+    const [exp, shareResultText] = yield ask(secretQuestion);
+    const bobResult = g.pow(exp).mod(p);
+    logger.info(`${shareResultText}${bobResult}`);
+    const [aliceResult, completionText] = yield ask(textIter.next().value);
+    const key = aliceResult.pow(exp).mod(p);
+    logger.success(`${completionText}${key}`);
+    rl.close();
+}
+
+const rl = readline.createInterface({
+    input: process.stdin,
+    output: process.stdout
+});
+
+const text = new Set([
+    'Enter the base number `g`:',
+    'Enter the modulus `p` (should be a sufficiently large prime):\n',
+    'Enter your secret exponent:\n',
+    'Share this result with your friend:\n',
+    'Enter your friend\'s result:\n',
+    'Use the following symmetric key for your secret communication:\n'
+]);
+
+module.exports = () => (
+    // textIter = text[Symbol.iterator]();
+    textIter = text.values(),
+
+    // Start the generators...GO!
+    getSecretIter = getSecret(textIter.next().value),
+    getSecretIter.next(),
+
+    // TODO: How to prevent the function return value from being logged to stdout.
+    ''
+);
+

index.js → src/index.js

@@ -12,6 +12,7 @@
 
 const bignum = require('bignum');
 const crypto = require('crypto');
+const dh = require('./dh');
 let sharedKey = null;
 
 const convertKey = key => {
@@ -32,10 +33,7 @@ const decode = (msg, key) => {
 
     return toDecode.split(' ')
         .map(c => String.fromCharCode(
-            bignum.xor(
-                c,
-                secret
-            )
+            bignum.xor(c, secret)
         ))
         .join('');
 };
@@ -44,11 +42,9 @@ const encode = (msg, key) => {
     const secret = convertKey(key || sharedKey);
 
     const encoded = msg.split('')
-        .map(c => bignum.xor(
-            c.charCodeAt(),
-            secret
-        ))
-        .join(' ');
+        .map(c =>
+            bignum.xor(c.charCodeAt(), secret)
+        ).join(' ');
 
     return new Buffer(encoded, 'utf8').toString('base64');
 };
@@ -69,6 +65,9 @@ const generateKey = n => {
     return bignum(res.concat(generateKey(--n)).join(''));
 };
 
+const generatePrime = n =>
+    bignum.prime(n || 512);
+
 const getKey = () =>
     sharedKey;
 
@@ -79,7 +78,9 @@ const setKey = key => {
 module.exports = {
     decode,
     encode,
+    generateDHKey: dh,
     generateKey,
+    generatePrime,
     getKey,
     setKey
 };