diff --git a/paste/views.py b/paste/views.py
index bd31d36..3c40c2c 100644
--- a/paste/views.py
+++ b/paste/views.py
@@ -7,7 +7,7 @@
 
 from db import cursor
 from paste import model
-from util import highlight, redirect, request_content, id_url, b64_id, id_b64
+from util import highlight, redirect, request_content, id_url, b66_int, int_b66
 
 paste = Blueprint('paste', __name__)
 
@@ -30,7 +30,7 @@ def post():
     if not id:
         id, uuid = model.insert(content)
 
-    url = id_url(b64=id_b64(id, filename=filename))
+    url = id_url(b66=int_b66(id, filename=filename))
     uuid = UUID(bytes=uuid) if uuid else '[redacted]'
     return redirect(url, "{}\nuuid: {}\n".format(url, uuid))
 
@@ -45,12 +45,12 @@ def put(uuid):
 
     id, _ = model.get_digest(content)
     if id:
-        url = id_url(b64=id_b64(id))
+        url = id_url(b66=int_b66(id))
         return redirect(url, "Paste already exists.\n", 409)
 
     id = model.put(uuid, content)
     if id:
-        url = id_url(b64=id_b64(id, filename=filename))
+        url = id_url(b66=int_b66(id, filename=filename))
         return redirect(url, "{} updated.\n".format(url), 200)
 
     return "Not found.\n", 404
@@ -61,19 +61,20 @@ def delete(uuid):
     uuid = UUID(uuid).bytes
     id = model.delete(uuid)
     if id:
-        url = id_url(b64=id_b64(id))
+        url = id_url(b66=int_b66(id))
         return redirect(url, "{} deleted.\n".format(url), 200)
     return "Not found.\n", 404
 
-@paste.route('/<string(length=4):b64>')
-@paste.route('/<string(length=4):b64>/<lexer>')
+@paste.route('/<string(length=4):b66>')
+@paste.route('/<string(length=4):b66>/<lexer>')
 @cursor
-def get(b64, lexer=None):
-    id = b64_id(b64)
-    if not id:
+def get(b66, lexer=None):
+    try:
+        id = b66_int(b66)
+    except ValueError:
         return "Invalid id.\n", 400
 
-    mimetype, _ = guess_type(b64)
+    mimetype, _ = guess_type(b66)
 
     content = model.get_content(id)
     if not content:
diff --git a/requirements.txt b/requirements.txt
index 4834efd..ab0b981 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,5 @@ Flask>=0.11-dev
 Werkzeug>=0.10-dev
 PyYAML>=3.11
 mysql-connector-python>=2.0.2
-bitstring>=3.1.3
 Pygments>=2.0.1
 requests>=2.5.0
diff --git a/url/views.py b/url/views.py
index bfbc67e..63f4c9b 100644
--- a/url/views.py
+++ b/url/views.py
@@ -1,15 +1,18 @@
 from flask import Blueprint
 
 from db import cursor
-from util import redirect, request_content, id_url, b85_id, id_b85
+from util import redirect, request_content, id_url, int_b66, b66_int
 from url import model
 
 url = Blueprint('url', __name__)
 
-@url.route('/<string(length=3):b85>')
+@url.route('/<string(length=3):b66>')
 @cursor
-def get(b85):
-    id = b85_id(b85)
+def get(b66):
+    try:
+        id = b66_int(b66)
+    except ValueError:
+        return 'Invalid id.\n', 400
 
     content = model.get_content(id)
     if not content:
@@ -32,5 +35,5 @@ def post():
     if not id:
         id = model.insert(content)
 
-    url = id_url(b85=id_b85(id))
+    url = id_url(b66=int_b66(id, 3))
     return redirect(url, "{}\n".format(url), 200)
diff --git a/util.py b/util.py
index 612c9f7..825b081 100644
--- a/util.py
+++ b/util.py
@@ -1,9 +1,4 @@
 from os import path
-from base64 import urlsafe_b64encode, urlsafe_b64decode, b85encode, b85decode
-from bitstring import Bits
-import binascii
-
-from urllib.parse import quote, unquote
 
 from flask import Response, render_template, current_app, request, url_for
 
@@ -12,6 +7,8 @@
 from pygments.formatters import HtmlFormatter
 from pygments.util import ClassNotFound
 
+b66c = 'QwdJxskgt6BE.levhL0zWNj8~1P_ZbHDq7YrpGOIX5CyimfK-cMoAR49FaUn3VT2Su'
+
 def redirect(location, rv, code=302):
     response = current_app.response_class(rv, code)
     response.headers['Location'] = location
@@ -38,26 +35,17 @@ def request_content():
 
     return None, None
 
-def id_b64(id, filename=None):
-    b64 = urlsafe_b64encode(Bits(length=24, int=int(id)).bytes)
+def int_b66(i, length=4, filename=None):
+    i = int(i)
+    b66 = ''
+    while i != 0:
+        i, n = divmod(i, len(b66c))
+        b66 = b66c[n] + b66
     ext = path.splitext(filename)[1] if filename else None
-    return b''.join((b64, ext.encode('utf-8'))) if ext else b64
-
-def b64_id(b64):
-    root, _ = path.splitext(b64)
-
-    try:
-        return Bits(bytes=urlsafe_b64decode(root)).int
-    except binascii.Error:
-        pass
-
-def id_b85(id):
-    b85 = b85encode(Bits(length=16, int=int(id)).bytes)
-    return quote(b85)
+    return '{:{zero}>{length}}'.format(''.join(b66, ext) if ext else b66, length=length, zero=b66c[0])
 
-def b85_id(b85):
-    b85 = unquote(b85)
-    return Bits(bytes=b85decode(b85)).int
+def b66_int(s):
+    return sum(b66c.index(c) * len(b66c) ** (len(s) - i - 1) for i, c in enumerate(s))
 
 def id_url(**kwargs):
     return url_for('.get', _external=True, _scheme='https', **kwargs)