mirror of
https://github.com/amark/gun.git
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333 lines
15 KiB
JavaScript
333 lines
15 KiB
JavaScript
;(function(){
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/*
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Security, Encryption, and Authorization: SEA.js
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*/
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// NECESSARY PRE-REQUISITE: http://gun.js.org/explainers/data/security.html
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/* THIS IS AN EARLY ALPHA!!! */
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if(typeof require !== "undefined"){ var Gun = require('./gun') }
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if(typeof window !== "undefined"){ var Gun = window.Gun }
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// let's extend the gun chain with a `user` function.
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// only one user can be logged in at a time, per gun instance.
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Gun.chain.user = function(){
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var root = this.back(-1); // always reference the root gun instance.
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var user = root._.user || (root._.user = root.chain()); // create a user context.
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user.create = User.create; // attach a factory method to it.
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user.auth = User.auth; // and a login method.
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return user; // return the user!
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}
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// EXAMPLE! Use it this way:
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;(function(){return;
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localStorage.clear();
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var gun = Gun();
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var user = gun.user();
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Gun.on('auth', function(at){
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// do something once logged in.
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});
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Gun.on('secure', function(at){
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// enforce some rules about shared app level data
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var no;
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if(no){ return }
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this.to.next(at);
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});
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user.create("test", "password"); // create a user from a username alias and a password phrase.
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user.auth("test", "password"); // authenticate and log in the user!
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}());
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// How does it work?
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function User(){};
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// Well first we have to actually create a user. That is what this function does.
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User.create = function(alias, pass, cb){
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var root = this.back(-1);
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cb = cb || function(){};
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// Because more than 1 user might have the same username, we treat the alias as a list of those users.
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root.get('alias/'+alias).get(function(at, ev){
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ev.off();
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if(at.put){
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// If we can enforce that a user name is already taken, it might be nice to try, but this is not guaranteed.
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return cb({err: Gun.log("User already created!")});
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}
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var user = {alias: alias, salt: Gun.text.random(64)};
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// pseudo-randomly create a salt, then use CryptoJS's PBKDF2 function to extend the password with it.
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SEA.proof(pass, user.salt, function(proof){
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// this will take some short amount of time to produce a proof, which slows brute force attacks.
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var pair = SEA.pair();
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// now we have generated a brand new ECDSA key pair for the user account.
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user.pub = pair.pub;
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// the user's public key doesn't need to be signed. But everything else needs to be signed with it!
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user.alias = SEA.write(alias, pair.priv);
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user.salt = SEA.write(user.salt, pair.priv);
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// to keep the private key safe, we AES encrypt it with the proof of work!
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user.auth = SEA.write(SEA.en(pair.priv, proof), pair.priv);
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var tmp = 'pub/'+pair.pub;
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//console.log("create", user, pair.pub);
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// awesome, now we can actually save the user with their public key as their ID.
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root.get(tmp).put(user);
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// next up, we want to associate the alias with the public key. So we add it to the alias list.
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var ref = root.get('alias/'+alias).put(Gun.obj.put({}, tmp, Gun.val.rel.ify(tmp)));
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// callback that the user has been created. (Note: ok = 0 because we didn't wait for disk to ack)
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cb({ok: 0, pub: pair.pub});
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});
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});
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}
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// now that we have created a user, we want to authenticate them!
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User.auth = function(alias, pass, cb){
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var root = this.back(-1);
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cb = cb || function(){};
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// load all public keys associated with the username alias we want to log in with.
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root.get('alias/'+alias).get(function(at, ev){
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ev.off();
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if(!at.put){
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// if no user, don't do anything.
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return cb({err: Gun.log("No user!")});
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}
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// then attempt to log into each one until we find ours!
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// (if two users have the same username AND the same password... that would be bad)
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Gun.obj.map(at.put, function(val, key){
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// grab the account associated with this public key.
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root.get(key).get(function(at, ev){
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key = key.slice(4);
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ev.off();
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if(!at.put){ return cb({err: "Public key does not exist!"}) }
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// attempt to PBKDF2 extend the password with the salt. (Verifying the signature gives us the plain text salt.)
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SEA.proof(pass, SEA.read(at.put.salt, key), function(proof){
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// the proof of work is evidence that we've spent some time/effort trying to log in, this slows brute force.
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var priv = SEA.de(SEA.read(at.put.auth, key), proof);
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// now we have AES decrypted the private key, from when we encrypted it with the proof at registration.
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if(priv){ // if we were successful, then that means...
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// we're logged in!
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var user = root._.user;
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// add our credentials in-memory only to our root gun instance
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user._ = at.gun._;
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// so that way we can use the credentials to encrypt/decrypt data
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user._.is = user.is = {};
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// that is input/output through gun (see below)
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user._.sea = priv;
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user._.pub = key;
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//console.log("authorized", user._);
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// callbacks success with the user data credentials.
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cb(user._);
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// emit an auth event, useful for page redirects and stuff.
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Gun.on('auth', user._);
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return;
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}
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// Or else we failed to log in...
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console.log("Failed to sign in!");
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cb({err: "Attempt failed"});
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});
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});
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});
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});
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}
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// After we have a GUN extension to make user registration/login easy, we then need to handle everything else.
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// We do this with a GUN adapter, we first listen to when a gun instance is created (and when its options change)
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Gun.on('opt', function(at){
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if(!at.sea){ // only add SEA once per instance, on the "at" context.
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at.sea = {own: {}};
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at.gun.on('in', security, at); // now listen to all input data, acting as a firewall.
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at.gun.on('out', signature, at); // and output listeners, to encrypt outgoing data.
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}
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this.to.next(at); // make sure to call the "next" middleware adapter.
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});
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// Alright, this next adapter gets run at the per node level in the graph database.
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// This will let us verify that every property on a node has a value signed by a public key we trust.
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// If the signature does not match, the data is just `undefined` so it doesn't get passed on.
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// If it does match, then we transform the in-memory "view" of the data into its plain value (without the signature).
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// Now NOTE! Some data is "system" data, not user data. Example: List of public keys, aliases, etc.
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// This data is self-enforced (the value can only match its ID), but that is handled in the `security` function.
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// From the self-enforced data, we can see all the edges in the graph that belong to a public key.
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// Example: pub/ASDF is the ID of a node with ASDF as its public key, signed alias and salt, and
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// its encrypted private key, but it might also have other signed values on it like `profile = <ID>` edge.
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// Using that directed edge's ID, we can then track (in memory) which IDs belong to which keys.
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// Here is a problem: Multiple public keys can "claim" any node's ID, so this is dangerous!
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// This means we should ONLY trust our "friends" (our key ring) public keys, not any ones.
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// I have not yet added that to SEA yet in this alpha release. That is coming soon, but beware in the meanwhile!
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Gun.on('node', function(at){ // TODO: Warning: Need to switch to `gun.on('node')`! Do not use `Gun.on('node'` in your apps!
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var own = (at.gun.back(-1)._).sea.own, soul = at.get, pub = own[soul] || soul.slice(4), vertex = (at.gun._).put;
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Gun.node.is(at.put, function(val, key, node){ // for each property on the node.
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vertex[key] = node[key] = val = SEA.read(val, pub); // verify signature and get plain value.
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if(val && val['#'] && (key = Gun.val.rel.is(val))){ // if it is a relation / edge
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if('alias/' === soul.slice(0,6)){ return } // if it is itself
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own[key] = pub; // associate the public key with a node
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}
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});
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})
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// signature handles data output, it is a proxy to the security function.
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function signature(at){
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at.user = at.gun.back(-1)._.user;
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security.call(this, at);
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}
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// okay! The security function handles all the heavy lifting.
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// It needs to deal read and write of input and output of system data, account/public key data, and regular data.
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// This is broken down into some pretty clear edge cases, let's go over them:
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function security(at){
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var cat = this.as, sea = cat.sea, to = this.to;
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if(at.get){
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// if there is a request to read data from us, then...
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var soul = at.get['#'];
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if(soul){ // for now, only allow direct IDs to be read.
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if('alias' === soul){ // Allow reading the list of usernames/aliases in the system?
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return to.next(at); // yes.
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} else
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if('alias/' === soul.slice(0,6)){ // Allow reading the list of public keys associated with an alias?
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return to.next(at); // yes.
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} else { // Allow reading everything?
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return to.next(at); // yes // TODO: No! Make this a callback/event that people can filter on.
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}
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}
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}
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if(at.put){
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// if there is a request to write data to us, then...
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var no, tmp, u;
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Gun.obj.map(at.put, function(node, soul){ // for each over every node in the graph
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if(no){ return no = true }
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if(Gun.obj.empty(node, '_')){ return } // ignore empty updates, don't reject them.
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if('alias' === soul){ // special case for shared system data, the list of aliases.
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Gun.obj.map(node, function(val, key){ // for each over the node to look at each property/value.
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if('_' === key){ return } // ignore meta data
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if(!val){ return no = true } // data MUST exist
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if('alias/'+key !== Gun.val.rel.is(val)){ // in fact, it must be EXACTLY equal to itself
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return no = true; // if it isn't, reject.
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}
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});
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} else
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if('alias/' === soul.slice(0,6)){ // special case for shared system data, the list of public keys for an alias.
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Gun.obj.map(node, function(val, key){ // for each over the node to look at each property/value.
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if('_' === key){ return } // ignore meta data
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if(!val){ return no = true } // data MUST exist
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if(key === Gun.val.rel.is(val)){ return } // and the ID must be EXACTLY equal to its property
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return no = true; // that way nobody can tamper with the list of public keys.
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});
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} else
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if('pub/' === soul.slice(0,4)){ // special case, account data for a public key.
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tmp = soul.slice(4); // ignore the 'pub/' prefix on the public key.
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Gun.obj.map(node, function(val, key){ // for each over the account data, looking at each property/value.
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if('_' === key){ return } // ignore meta data.
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if('pub' === key){
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if(val === tmp){ return } // the account MUST have a `pub` property that equals the ID of the public key.
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return no = true; // if not, reject the update.
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}
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if(at.user){ // if we are logged in
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if(tmp === at.user._.pub){ // as this user
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val = node[key] = SEA.write(val, at.user._.sea); // then sign our updates as we output them.
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} // (if we are lying about our signature, other peer's will reject our update)
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}
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if(u === (val = SEA.read(val, tmp))){ // make sure the signature matches the account it claims to be on.
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return no = true; // reject any updates that are signed with a mismatched account.
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}
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});
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} else
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if(at.user && (tmp = at.user._.sea)){ // not special case, if we are logged in, then
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Gun.obj.map(node, function(val, key){ // any data we output needs to
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if('_' === key){ return }
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node[key] = SEA.write(val, tmp); // be signed by our logged in account.
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});
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} else // TODO: BUG! These two if-statements are not exclusive to each other!!!
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if(tmp = sea.own[soul]){ // not special case, if we receive an update on an ID associated with a public key, then
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Gun.obj.map(node, function(val, key){ // for each over the property/values
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if('_' === key){ return }
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if(u === (val = SEA.read(val, tmp))){ // and verify they were signed by the associated public key!
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return no = true; // reject the update if it fails to match.
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}
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});
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} else { // reject any/all other updates by default.
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return no = true;
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}
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});
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if(no){ // if we got a rejection then...
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if(!at || !Gun.tag.secure){ return }
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Gun.on('secure', function(at){ // (below) emit a special event for the developer to handle security.
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this.off();
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if(!at){ return }
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to.next(at); // and if they went ahead and explicitly called "next" (to us) with data, then approve.
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});
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Gun.on('secure', at);
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return; // else wise, reject.
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}
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//console.log("SEA put", at.put);
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// if we did not get a rejection, then pass forward to the "next" adapter middleware.
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return to.next(at);
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}
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to.next(at); // pass forward any data we do not know how to handle or process (this allows custom security protocols).
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}
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function SEA(){};
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// create a wrapper library around CryptoJS and JSRSAsign.
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// of course, these libraries are required. A bundle is included in lib/cryptography.js
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if(typeof CryptoJS === "undefined"){ console.log("Error: CryptoJS required!") }
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if(typeof KJUR === "undefined"){ console.log("Error: JSRSAsign required!") }
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// now wrap the various AES, ECDSA, PBKDF2 functions we called above.
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SEA.proof = function(pass,salt,cb){
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cb(CryptoJS.PBKDF2(pass, salt, {keySize: 512/32, iterations: 100}).toString(CryptoJS.enc.Base64));
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};
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SEA.pair = function(){
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var master = new KJUR.crypto.ECDSA({"curve": 'secp256r1'});
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var pair = master.generateKeyPairHex();
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return {pub: pair.ecpubhex, priv: pair.ecprvhex};
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};
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SEA.sign = function(m, p){
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var sig = new KJUR.crypto.Signature({'alg': 'SHA256withECDSA'});
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sig.initSign({'ecprvhex': p, 'eccurvename': 'secp256r1'});
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sig.updateString(JSON.stringify(m));
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return sig.sign();
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}
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SEA.verify = function(m, p, s){
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var sig = new KJUR.crypto.Signature({'alg': 'SHA256withECDSA', 'prov': "cryptojs/jsrsa"}), yes;
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try{
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sig.initVerifyByPublicKey({'ecpubhex': p, 'eccurvename': 'secp256r1'});
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sig.updateString(JSON.stringify(m));
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yes = sig.verify(s);
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}catch(e){Gun.log(e)}
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return yes;
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}
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SEA.write = function(m, p){
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return 'SEA'+JSON.stringify([m,SEA.sign(m,p)]);
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return JSON.stringify([m,SEA.sign(m,p)]);
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}
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SEA.read = function(m, p){
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if(!m){ return }
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if(!m.slice || 'SEA[' !== m.slice(0,4)){ return m }
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m = m.slice(3);
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try{m = JSON.parse(m);
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}catch(e){ return }
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m = m || '';
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if(SEA.verify(m[0], p, m[1])){
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return m[0];
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}
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}
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SEA.en = function(m, p){
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return CryptoJS.AES.encrypt(JSON.stringify(m), p, {format:SEA.froto}).toString();
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};
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SEA.de = function(m, p){
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var r;
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try{r = CryptoJS.AES.decrypt(m, p, {format:SEA.froto}).toString(CryptoJS.enc.Utf8);
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r = JSON.parse(r);
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}catch(e){};
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return r;
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};
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SEA.froto = {stringify:function(a){var b={ct:a.ciphertext.toString(CryptoJS.enc.Base64)};a.iv&&(b.iv=a.iv.toString());a.salt&&(b.s=a.salt.toString());return JSON.stringify(b)},parse:function(a){a=JSON.parse(a);var b=CryptoJS.lib.CipherParams.create({ciphertext:CryptoJS.enc.Base64.parse(a.ct)});a.iv&&(b.iv=CryptoJS.enc.Hex.parse(a.iv));a.s&&(b.salt=CryptoJS.enc.Hex.parse(a.s));return b}};
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Gun.SEA = SEA;
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// all done!
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// Obviously it is missing MANY necessary features. This is only an alpha release.
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// Please experiment with it, audit what I've done so far, and complain about what needs to be added.
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// SEA should be a full suite that is easy and seamless to use.
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// Again, scroll naer the top, where I provide an EXAMPLE of how to create a user and sign in.
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// Once logged in, the rest of the code you just read handled automatically signing/validating data.
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// But all other behavior needs to be equally easy, like opinionated ways of
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// Adding friends (trusted public keys), sending private messages, etc.
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// Cheers! Tell me what you think.
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}()); |