diff --git a/requirements.txt b/requirements.txt
index dc29c54..9425c02 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,7 @@ Werkzeug<1.0.0
 aniso8601
 argparse
 itsdangerous
-pbkdf2
+argon2-cffi
 pylibmc
 python-dateutil
 pytz
diff --git a/scoreboard/models.py b/scoreboard/models.py
index 35cdd46..814919d 100644
--- a/scoreboard/models.py
+++ b/scoreboard/models.py
@@ -22,11 +22,12 @@
 import logging
 import math
 import os
-import pbkdf2
 import re
 import sqlalchemy as sqlalchemy_base
 import time
 
+from argon2 import PasswordHasher
+
 from sqlalchemy import exc
 from sqlalchemy import func
 from sqlalchemy import orm
@@ -159,7 +160,7 @@ class User(db.Model):
     uid = db.Column(db.Integer, primary_key=True)
     email = db.Column(db.String(120), unique=True, nullable=False, index=True)
     nick = db.Column(db.String(80), unique=True, nullable=False, index=True)
-    pwhash = db.Column(db.String(48))  # pbkdf2.crypt == 48 bytes
+    pwhash = db.Column(db.String(48))  # argon2.PasswordHasher().hash
     admin = db.Column(db.Boolean, default=False, index=True)
     team_tid = db.Column(db.Integer, db.ForeignKey('team.tid'))
     create_ip = db.Column(db.String(45))     # max 45 bytes for IPv6
@@ -168,7 +169,8 @@ class User(db.Model):
     api_key_updated = db.Column(db.DateTime)
 
     def set_password(self, password):
-        self.pwhash = pbkdf2.crypt(password)
+        ph = PasswordHasher()
+        self.pwhash = ph.hash(password)
 
     def __repr__(self):
         return '<User: %s <%s>>' % (self.nick.encode('utf-8'), self.email)
@@ -253,7 +255,8 @@ def login_user(cls, email, password):
             user = cls.query.filter_by(email=email).one()
         except exc.InvalidRequestError:
             return None
-        if pbkdf2.crypt(password, user.pwhash) == user.pwhash:
+        ph = PasswordHasher()
+        if ph.verify(user.pwhash, password):
             if flask.has_request_context():
                 user.last_login_ip = flask.request.remote_addr
                 db.session.commit()
@@ -372,7 +375,7 @@ class Challenge(db.Model):
     points = db.Column(db.Integer, nullable=False)
     min_points = db.Column(db.Integer, nullable=True)
     validator = db.Column(db.String(24), nullable=False,
-                          default='static_pbkdf2')
+                          default='static_argon2')
     answer_hash = db.Column(db.String(48))  # Protect answers
     unlocked = db.Column(db.Boolean, default=False)
     weight = db.Column(db.Integer, nullable=False)  # Order for display
@@ -493,7 +496,7 @@ def prereq_solved(self, prereq, team):
 
     @classmethod
     def create(cls, name, description, points, answer, unlocked=False,
-               validator='static_pbkdf2'):
+               validator='static_argon2'):
         challenge = cls()
         challenge.name = name
         challenge.description = description
@@ -652,6 +655,7 @@ class Answer(db.Model):
 
     @classmethod
     def create(cls, challenge, team, answer_text):
+        ph = PasswordHasher()
         answer = cls()
         answer.first_blood = 0
         if not challenge.solves:
@@ -661,7 +665,7 @@ def create(cls, challenge, team, answer_text):
         answer.team = team
         answer.timestamp = datetime.datetime.utcnow()
         if answer_text:
-            answer.answer_hash = pbkdf2.crypt(team.name + answer_text)
+            answer.answer_hash = ph.hash(team.name + answer_text)
         if flask.request:
             answer.submit_ip = flask.request.remote_addr
         db.session.add(answer)
diff --git a/scoreboard/tests/base.py b/scoreboard/tests/base.py
index 38d0bc3..932fbdd 100644
--- a/scoreboard/tests/base.py
+++ b/scoreboard/tests/base.py
@@ -21,7 +21,7 @@
 import logging
 import os
 import os.path
-import pbkdf2
+from argon2 import PasswordHasher
 import time
 import unittest
 
@@ -107,8 +107,8 @@ class RestTestCase(BaseTestCase):
     def setUp(self):
         super(RestTestCase, self).setUp()
         # Monkey patch pbkdf2 for speed
-        self._orig_pbkdf2 = pbkdf2.crypt
-        pbkdf2.crypt = self._pbkdf2_dummy
+        self._orig_argon2 = PasswordHasher().hash
+        PasswordHasher().hash = self._argon2_dummy
         # Setup some special clients
         self.admin_client = AdminClient(
                 self.app, self.app.response_class)
@@ -117,7 +117,7 @@ def setUp(self):
 
     def tearDown(self):
         super(RestTestCase, self).tearDown()
-        pbkdf2.crypt = self._orig_pbkdf2
+        PasswordHasher().hash = self._orig_argon2
 
     def postJSON(self, path, data, client=None):
         client = client or self.client
@@ -139,7 +139,7 @@ def swapClient(self, client):
         self.client = old_client
 
     @staticmethod
-    def _pbkdf2_dummy(value, *unused_args):
+    def _argon2_dummy(value, *unused_args):
         return value
 
 
diff --git a/scoreboard/validators/__init__.py b/scoreboard/validators/__init__.py
index 816411d..7569c03 100644
--- a/scoreboard/validators/__init__.py
+++ b/scoreboard/validators/__init__.py
@@ -13,14 +13,14 @@
 # limitations under the License.
 
 
-from . import static_pbkdf2
+from . import static_argon2
 from . import per_team
 from . import nonce
 from . import regex
 
 _Validators = {
-        'static_pbkdf2': static_pbkdf2.StaticPBKDF2Validator,
-        'static_pbkdf2_ci': static_pbkdf2.CaseStaticPBKDF2Validator,
+        'static_argon2': static_argon2.StaticArgon2Validator,
+        'static_argon2_ci': static_argon2.CaseStaticArgon2Validator,
         'per_team': per_team.PerTeamValidator,
         'nonce_166432': nonce.Nonce_16_64_Base32_Validator,
         'nonce_245632': nonce.Nonce_24_56_Base32_Validator,
@@ -31,7 +31,7 @@
 
 
 def GetDefaultValidator():
-    return 'static_pbkdf2'
+    return 'static_argon2'
 
 
 def GetValidatorForChallenge(challenge):
diff --git a/scoreboard/validators/static_pbkdf2.py b/scoreboard/validators/static_argon2.py
similarity index 76%
rename from scoreboard/validators/static_pbkdf2.py
rename to scoreboard/validators/static_argon2.py
index 54247c8..00aa836 100644
--- a/scoreboard/validators/static_pbkdf2.py
+++ b/scoreboard/validators/static_argon2.py
@@ -12,13 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import pbkdf2
+import argon2
 
 from scoreboard import utils
 from scoreboard.validators import base
 
 
-class StaticPBKDF2Validator(base.BaseValidator):
+class StaticArgon2Validator(base.BaseValidator):
     """PBKDF2-based secrets, everyone gets the same flag."""
 
     name = 'Static'
@@ -27,14 +27,14 @@ def validate_answer(self, answer, unused_team):
         if not self.challenge.answer_hash:
             return False
         return utils.compare_digest(
-                pbkdf2.crypt(answer, self.challenge.answer_hash),
+                argon2.PasswordHasher().hash(answer, self.challenge.answer_hash),
                 self.challenge.answer_hash)
 
     def change_answer(self, answer):
-        self.challenge.answer_hash = pbkdf2.crypt(answer)
+        self.challenge.answer_hash = argon2.PasswordHasher().hash(answer)
 
 
-class CaseStaticPBKDF2Validator(StaticPBKDF2Validator):
+class CaseStaticArgon2Validator(StaticArgon2Validator):
     """PBKDF2-based secrets, case insensitive."""
 
     name = 'Static (Case Insensitive)'
@@ -42,9 +42,9 @@ class CaseStaticPBKDF2Validator(StaticPBKDF2Validator):
     def validate_answer(self, answer, team):
         if not isinstance(answer, str):
             return False
-        return super(CaseStaticPBKDF2Validator, self).validate_answer(
+        return super(CaseStaticArgon2Validator, self).validate_answer(
                 answer.lower(), team)
 
     def change_answer(self, answer):
-        return super(CaseStaticPBKDF2Validator, self).change_answer(
+        return super(CaseStaticArgon2Validator, self).change_answer(
                 answer.lower())