From 94632b37c9ba5c6376d84bba81ca0d8c737206cf Mon Sep 17 00:00:00 2001
From: Jeff Becker <ampernand@gmail.com>
Date: Sun, 29 Jan 2017 18:15:02 -0500
Subject: [PATCH] initial chacha20 code;

---
 contrib/js/{contrib => nntpchan}/chacha20.js | 18 ++++--
 contrib/js/nntpchan/crypto.js                | 68 ++++++++++++++++++++
 contrib/static/test.html                     | 22 +++++++
 3 files changed, 101 insertions(+), 7 deletions(-)
 rename contrib/js/{contrib => nntpchan}/chacha20.js (90%)
 create mode 100644 contrib/js/nntpchan/crypto.js
 create mode 100644 contrib/static/test.html

diff --git a/contrib/js/contrib/chacha20.js b/contrib/js/nntpchan/chacha20.js
similarity index 90%
rename from contrib/js/contrib/chacha20.js
rename to contrib/js/nntpchan/chacha20.js
index e9247bd..8f3c382 100644
--- a/contrib/js/contrib/chacha20.js
+++ b/contrib/js/nntpchan/chacha20.js
@@ -6,6 +6,7 @@
 // See for details: http://cr.yp.to/chacha/chacha-20080128.pdf
 
 function U8TO32_LE(x, i) {
+    if(x === undefined) return;
   return x[i] | (x[i+1]<<8) | (x[i+2]<<16) | (x[i+3]<<24);
 }
 
@@ -20,7 +21,7 @@ function ROTATE(v, c) {
   return (v << c) | (v >>> (32 - c));
 }
 
-var Chacha20 = function(key, nonce, counter) {
+function Chacha20(key, nonce, counter) {
   this.input = new Uint32Array(16);
 
   // https://tools.ietf.org/html/draft-irtf-cfrg-chacha20-poly1305-01#section-2.3
@@ -103,14 +104,17 @@ Chacha20.prototype.keystream = function(dst, len) {
   this.encrypt(dst, dst, len);
 };
 
-// additions to make it easier and export it as a module
+var Cipher = Chacha20;
 
-exports.Cipher = Chacha20;
+var chacha_encrypt;
+var chacha_decrypt;
 
-exports.encrypt = exports.decrypt = function(key, nonce, data)
+chacha_decrypt = function(key, nonce, data)
 {
-  var cipher = new Chacha20(key, nonce);
-  var ret = new Buffer(data.length);
+  var cipher = new Chacha20(key, nonce, 0);
+  var ret = new Uint8Array(data.length);
   cipher.encrypt(ret, data, data.length);
   return ret;
-}
\ No newline at end of file
+};
+
+chacha_encrypt = chacha_decrypt;
diff --git a/contrib/js/nntpchan/crypto.js b/contrib/js/nntpchan/crypto.js
new file mode 100644
index 0000000..b5158e6
--- /dev/null
+++ b/contrib/js/nntpchan/crypto.js
@@ -0,0 +1,68 @@
+
+var nntpchan_ToBase64 = function (u8) {
+    return btoa(String.fromCharCode.apply(null, u8));
+};
+
+var nntpchan_FromBase64 = function (str) {
+    return atob(str).split('').map(function (c) { return c.charCodeAt(0); });
+};
+
+
+function nntpchan_keygen() {
+    var crypto = window.crypto || window.msCrypto;
+    if(!crypto) {
+        throw "no crypto";
+    }
+    var key = new Uint8Array(32);
+    crypto.getRandomValues(key);
+    var nonce = new Uint8Array(12);
+    crypto.getRandomValues(nonce);
+    return nntpchan_ToBase64(key) + ":" + nntpchan_ToBase64(nonce);
+}
+
+function nntpchan_chacha_nonce(blob) {
+    var parts = blob.split(":");
+    return nntpchan_FromBase64(parts[1]);
+}
+
+function nntpchan_chacha_key(blob) {
+    var parts = blob.split(":");
+    return nntpchan_FromBase64(parts[0]);
+}
+
+// encrypt text from an element using symettric key and nonce
+// output to element.innerHTML as base64
+function nntpchan_encrypt_element(inelem, outelem, key, nonce) {
+    var plaintext = inelem.innerHTML;
+    console.log(plaintext);
+    var ciphertext = chacha_encrypt(key, nonce, plaintext);
+    outelem.innerHTML = nntpchan_ToBase64(ciphertext);
+}
+
+// encrypt text from an element using symettric key and nonce
+// output to element.innerHTML as base64
+function nntpchan_decrypt_element(inelem, outelem, key, nonce) {
+    var ciphertext = nntpchan_FromBase64(inelem.innerHTML);
+    console.log(ciphertext);
+    var plaintext = chacha_decrypt(key, nonce, ciphertext);
+    console.log(plaintext);
+    while(outelem.children.length > 0) {
+        outelem.children[0].remove();
+    }
+    outelem.appendChild(document.createTextNode(plaintext));
+}
+
+
+
+function nntpchan_crypto_test() {
+    console.log("begin crypto test");
+    var genelem = $("#test_keygen");
+    genelem[0].innerHTML = nntpchan_keygen();
+    var inelem = $("#encrypt_in")[0];
+    var outelem = $("#encrypt_out")[0];
+    var decryptelem = $("#decrypt_out")[0];
+    var key = nntpchan_chacha_key(genelem[0].innerHTML);
+    var nonce = nntpchan_chacha_nonce(genelem[0].innerHTML);
+    nntpchan_encrypt_element(inelem, outelem, key, nonce);
+    nntpchan_decrypt_element(outelem, decryptelem, key, nonce);
+}
diff --git a/contrib/static/test.html b/contrib/static/test.html
new file mode 100644
index 0000000..8a1c0e4
--- /dev/null
+++ b/contrib/static/test.html
@@ -0,0 +1,22 @@
+<html>
+    <head>
+        <title> crypto test page </title>
+        <script src="nntpchan.js"></script>
+    </head>
+    <body>
+        <div id="test_keygen">
+
+        </div>
+        <div id="encrypt_in">
+            test encrypt
+        </div>
+        <div id="encrypt_out">
+        </div>
+        <div id="decrypt_out">
+            
+        </div>
+        <script>
+         nntpchan_crypto_test();
+        </script>
+    </body>
+</html>