1 files changed, 183 insertions, 0 deletions
diff --git a/proper-random/django/srpproject/srp/views.py b/proper-random/django/srpproject/srp/views.py
new file mode 100644
index 0000000..9d2563b
--- /dev/null
+++ b/proper-random/django/srpproject/srp/views.py
@@ -0,0 +1,183 @@
+# Create your views here.
+
+from django.http import HttpResponse
+
+from srp import models
+
+###
+### General methods
+###
+
+# We need randomly generated salts. This is about 100 bits of entropy.
+def generate_salt():
+    import string, random   
+    randomgen = random.SystemRandom()
+    salt_chars = "!@#$%^&*(),./?`~;:" + string.ascii_letters + string.digits
+    return "".join([randomgen.choice(salt_chars) for i in range(0,16)])
+
+# We want to avoid information leakage. For users that don't exist, we need salts to be consistent.
+# These "fake" salts are seeded with the username and the django secret_key. They're not as random
+# as true salts should be, but they should be indistinguishable to a hacker who isn't sure whether
+# or not an account exists.
+def generate_fake_salt(I):
+    import string, random, settings, hashlib
+    random.seed("%s:%s" % (I, settings.SECRET_KEY))
+    salt_chars = "!@#$%^&*(),./?`~;:" + string.ascii_letters + string.digits    
+    salt = "".join([random.choice(salt_chars) for i in range(0,16)])
+    return salt, int(hashlib.sha256("%s:%s" % (salt, settings.SECRET_KEY)).hexdigest(), 16)
+    
+def login_page(request):
+    return HttpResponse("""<html>
+ <head>
+    <script src="http://%s/srp-test/javascript/SHA256.js"></script>
+    <script src="http://%s/srp-test/javascript/prng4.js"></script>
+    <script src="http://%s/srp-test/javascript/rng.js"></script>
+    <script src="http://%s/srp-test/javascript/jsbn.js"></script>
+    <script src="http://%s/srp-test/javascript/jsbn2.js"></script>
+    <script src="http://%s/srp-test/javascript/srp.js"></script>
+    <script type="text/javascript">
+        function srp_success()
+        {
+            alert("Authentication successful.");
+        }
+    </script>
+ </head>
+ <body>
+    <form action="." onsubmit="return srp_identify()">
+    Username: <input type="text" id="srp_username" /><br/>
+    Password: <input type="password" id="srp_password" /><br/>
+    <input type="submit"/>
+    </form>
+ </body>
+</html>""" % (request.get_host(), request.get_host(), request.get_host(),request.get_host(), request.get_host(), request.get_host()))
+
+def register_page(request):
+    return HttpResponse("""<html>
+ <head>
+    <script src="http://%s/srp-test/javascript/SHA256.js"></script>
+    <script src="http://%s/srp-test/javascript/prng4.js"></script>
+    <script src="http://%s/srp-test/javascript/rng.js"></script>
+    <script src="http://%s/srp-test/javascript/jsbn.js"></script>
+    <script src="http://%s/srp-test/javascript/jsbn2.js"></script>
+    <script src="http://%s/srp-test/javascript/srp.js"></script>
+    <script type="text/javascript">
+function register()
+{
+    if(document.getElementById("confirm_password").value != document.getElementById("srp_password").value)
+        alert("Passwords do not match");
+    else if(document.getElementById("srp_password").value == "")
+        alert("Password cannot be blank");
+    else
+        srp_register();
+    return false;
+};
+function srp_success()
+{
+    alert("Authentication successful.");
+};
+    </script>
+ </head>
+ <body>
+    <form action="." onsubmit="return register()">
+    Username: <input type="text" id="srp_username" /><br/>
+    Password: <input type="password" id="srp_password" /><br/>
+    Password: <input type="password" id="confirm_password" /><br/>
+    <input type="submit"/>
+    </form>
+ </body>
+</html>""" % (request.get_host(), request.get_host(), request.get_host(),request.get_host(), request.get_host(), request.get_host()))
+
+###
+### User Registration
+###
+
+# Step 1. A client submits a username. If the username is available, we generate a salt, store it, and return it.
+# Otherwise, we return an error.
+def register_salt(request):
+    if models.User.objects.filter(name=request.POST["I"]).count() > 0:
+        return HttpResponse("<error>Username already in use</error>", mimetype="text/xml")
+    request.session["srp_name"] = request.POST["I"]
+    request.session["srp_salt"] = generate_salt()
+    return HttpResponse("<salt>%s</salt>" % request.session["srp_salt"], mimetype="text/xml")
+    
+# Step 2. The client creates the password verifier and sends it to the server, along with a username.
+def register_user(request):
+    from django.contrib import auth
+    models.User(salt=request.session["srp_salt"], name=request.session["srp_name"], verifier=request.POST["v"]).save()
+    auth.models.User.objects.create_user(request.session["srp_name"],'', str(request.POST["v"]))
+    del request.session["srp_salt"]
+    del request.session["srp_name"]
+    return HttpResponse("<ok/>", mimetype="text/xml");
+    
+# Step 3: The client initiates the login process.
+
+###
+### User Login
+###
+
+# Step 1: The user sends an identifier and public ephemeral key, A
+# The server responds with the salt and public ephemeral key, B
+def handshake(request):
+    import random, hashlib
+    randomgen = random.SystemRandom()
+    request.session["srp_I"] = request.POST["I"]
+    A = int(request.POST["A"], 16)
+    request.session["srp_A"] = request.POST["A"]
+    g = 2
+    N = 125617018995153554710546479714086468244499594888726646874671447258204721048803
+    k = 88846390364205216646376352624313659232912717719075174937149043299744712465496
+    if A % N == 0:
+        return HttpResponse("<error>Invalid ephemeral key.</error>", mimetype="text/xml")
+    else:
+        try:
+            user = models.User.objects.get(name=request.session["srp_I"])
+            salt = user.salt
+            v = int(user.verifier, 16)
+        # We don't want to leak that the username doesn't exist. Make up a fake salt and verifier.
+        except models.User.DoesNotExist:
+            salt, x = generate_fake_salt(request.POST["I"])
+            v = pow(g, x, N)
+            
+        request.session["srp_v"] = hex(v)[2:-1]
+
+        # Ensure that B%N != 0
+        while True:
+            b = randomgen.getrandbits(32)
+            B = k*v + pow(g,b,N)
+            u =  int(hashlib.sha256("%s%s" % (hex(A)[2:-1],hex(B)[2:-1])).hexdigest(), 16)
+            if B % N != 0 and u % N != 0: break
+
+        response = "<r s='%s' B='%s' />" % (salt, hex(B)[2:-1])
+        # Ideally, we could return this response and then calculate M concurrently with the user
+        # Unfortunately, django isn't designed to do computations after responding.
+        # Maybe someone will find a way.
+        S = pow(A*pow(v,u,N), b, N)
+        request.session["srp_S"] = hex(S)[2:-1]
+        Mstr = "%s%s%s" % (hex(A)[2:-1],hex(B)[2:-1],hex(S)[2:-1])
+        response = "<r s='%s' B='%s' />" % (salt, hex(B)[2:-1])
+        request.session["srp_M"] = hashlib.sha256(Mstr).hexdigest()
+    return HttpResponse(response, mimetype="text/xml")
+
+# Step 2: The client sends its proof of S. The server confirms, and sends its proof of S.    
+def verify(request):
+    import hashlib
+    from django.contrib import auth
+    if request.POST["M"] == request.session["srp_M"]:
+        # H(A, M, K)
+        user = auth.authenticate(username=request.session["srp_I"], password=str(request.session["srp_v"]))
+        if user != None:
+            response = "<M>%s</M>" % hashlib.sha256("%s%s%s" % (request.session["srp_A"], request.session["srp_M"], request.session["srp_S"])).hexdigest()
+            auth.login(request, user)
+        else:
+            response = "<error>Authentication failed. This is likely a server problem.</error>"
+    else:
+        response = "<error>Invalid username or password.</error>"
+    try:
+        del request.session["srp_I"]
+        del request.session["srp_v"]
+        del request.session["srp_M"]
+        del request.session["srp_S"]
+        del request.session["srp_A"]
+    except KeyError:
+        pass
+    return HttpResponse(response, mimetype="text/xml")