diff --git a/src/httpaste/__main__.py b/src/httpaste/__main__.py
index 399417f..4a6aae4 100644
--- a/src/httpaste/__main__.py
+++ b/src/httpaste/__main__.py
@@ -92,6 +92,20 @@ def command_init_backend(**kwargs):
     config.backend.paste.init()
 
 
+def command_sanitize_backend(**kwargs):
+    """sanitize the backend
+    """
+
+    from httpaste import load_config
+
+    config, _ = load_config(kwargs.get('config'))
+
+    config, _ = load_config(kwargs.get('config'))
+
+    config.backend.user.sanitize()
+    config.backend.paste.sanitize()
+
+
 def parser():
 
     p = argparse.ArgumentParser(description='Process some integers.')
@@ -121,6 +135,11 @@ def parser():
         help=command_init_backend.__doc__)
     p_init_backend.add_argument('--config', '-c', required=True)
 
+    p_sanitize_backend = sp.add_parser(
+        'sanitize-backend',
+        help=command_sanitize_backend.__doc__)
+    p_sanitize_backend.add_argument('--config', '-c', required=True)
+
     return p
 
 
@@ -136,7 +155,8 @@ def main():
         'cgi': command_cgi,
         'fcgi': command_fcgi,
         'default-config': command_default_config,
-        'init-backend': command_init_backend
+        'init-backend': command_init_backend,
+        'sanitize-backend': command_sanitize_backend
     }[kwargs.pop('command')](**kwargs)
 
 
diff --git a/src/httpaste/backend/__init__.py b/src/httpaste/backend/__init__.py
index 2e176d9..48978a0 100644
--- a/src/httpaste/backend/__init__.py
+++ b/src/httpaste/backend/__init__.py
@@ -26,7 +26,7 @@ class SQLite(Backend):
 
     def __init__(self, parameters: SqliteParameters):
 
-        parameters['connection'] = get_sqlite_connection(parameters)
+        parameters = SqliteParameters(parameters.path, get_sqlite_connection(parameters))
 
         self.user = SqliteUser(parameters, User)
         self.paste = SqlitePaste(parameters, Paste)
diff --git a/src/httpaste/backend/file/__init__.py b/src/httpaste/backend/file/__init__.py
index a8d1126..9352f8f 100644
--- a/src/httpaste/backend/file/__init__.py
+++ b/src/httpaste/backend/file/__init__.py
@@ -58,6 +58,13 @@ class User(object):
 
         return user.init(self.path)
 
+    def sanitize(self):
+
+        if self.path.exists():
+            return user.sanitize(self.path, self.model_class, self.model_schema)
+
+        return None
+
 
 class Paste(object):
     """Filesystem paste model backend
@@ -96,3 +103,10 @@ class Paste(object):
     def init(self):
 
         return paste.init(self.path)
+
+    def sanitize(self):
+
+        if self.path.exists():
+            return paste.sanitize(self.path, self.model_class, self.model_schema)
+
+        return None
\ No newline at end of file
diff --git a/src/httpaste/backend/file/paste.py b/src/httpaste/backend/file/paste.py
index d27b7ca..dbeb341 100644
--- a/src/httpaste/backend/file/paste.py
+++ b/src/httpaste/backend/file/paste.py
@@ -5,6 +5,16 @@ acting as cells.
 """
 from pathlib import Path
 from ast import literal_eval
+from time import time
+
+
+COLUMNS = [
+    'data',
+    'data_hash',
+    'sub',
+    'expiration',
+    'encoding'
+]
 
 
 def load(
@@ -22,13 +32,7 @@ def load(
         return None
 
     cells = {}
-    for column in [
-        'data',
-        'data_hash',
-        'sub',
-        'timestamp',
-        'lifetime',
-        'encoding']:
+    for column in COLUMNS:
 
         cell = row.joinpath(column)
 
@@ -56,8 +60,7 @@ def load(
         cells['sub'],
         cells['data'],
         cells['data_hash'],
-        cells['timestamp'],
-        cells['lifetime'],
+        cells['expiration'],
         cells['encoding'])
 
 
@@ -68,13 +71,7 @@ def dump(model: object, path: Path, model_schema: type) -> None:
     row = path.joinpath(model.pid.hex())
     row.mkdir(parents=True, exist_ok=True)
 
-    for column in [
-        'data',
-        'data_hash',
-        'sub',
-        'timestamp',
-        'lifetime',
-            'encoding']:
+    for column in COLUMNS:
 
         cell = row.joinpath(column)
         cell_schema = getattr(model_schema, column)
@@ -102,6 +99,22 @@ def init(path: Path):
     return None
 
 
+def sanitize(path: Path, model_class: type, model_schema: type):
+
+    for row in path.iterdir():
+
+        expiration_cell = row.joinpath('expiration')
+
+        if not expiration_cell.exists():
+            continue
+
+        expiration = literal_eval(expiration_cell.read_text())
+
+        if expiration < int(time()) and expiration > 0:
+
+            delete(model_class(bytes.fromhex(row.name)), path)
+
+
 def _rm_tree(pth: Path):
     for child in pth.iterdir():
         if child.is_file():
diff --git a/src/httpaste/backend/file/user.py b/src/httpaste/backend/file/user.py
index 02255b2..21e32d0 100644
--- a/src/httpaste/backend/file/user.py
+++ b/src/httpaste/backend/file/user.py
@@ -6,6 +6,12 @@ acting as cells.
 from pathlib import Path
 from ast import literal_eval
 
+COLUMNS = [
+    'sub',
+    'key_hash',
+    'index',
+]
+
 
 def load(
         proto: object,
@@ -22,15 +28,17 @@ def load(
         return None
 
     cells = {}
-    for column in ['key_hash', 'index']:
+    for column in COLUMNS[1:]:
 
         cell = row.joinpath(column)
 
-        if getattr(model_schema, column) == bytes:
-
+        if not cell.exists():
+            cells[column] = None
+        elif getattr(model_schema, column) == bytes:
             cells[column] = cell.read_bytes()
+        elif getattr(model_schema, column) == str:
+            cells[column] = cell.read_text()
         else:
-
             cells[column] = literal_eval(cell.read_text())
 
     return model_class(
@@ -46,7 +54,7 @@ def dump(model: object, path: Path, model_schema: object) -> None:
     row = path.joinpath(model.sub.hex())
     row.mkdir(parents=True, exist_ok=True)
 
-    for column in ['key_hash', 'index']:
+    for column in COLUMNS[1:]:
 
         cell = row.joinpath(column)
 
@@ -74,6 +82,11 @@ def init(path: Path):
     return None
 
 
+def sanitize(path: Path, model_class: type, model_schema: type):
+
+    return None
+
+
 def _rm_tree(pth: Path):
     for child in pth.iterdir():
         if child.is_file():
diff --git a/src/httpaste/backend/sqlite/__init__.py b/src/httpaste/backend/sqlite/__init__.py
index 8bd14e5..5680f5c 100644
--- a/src/httpaste/backend/sqlite/__init__.py
+++ b/src/httpaste/backend/sqlite/__init__.py
@@ -45,6 +45,10 @@ class User(object):
 
         return user.init(self.connection)
 
+    def sanitize(self):
+
+        return user.sanitize(self.connection, self.model_class)
+
 
 class Paste(object):
     """SQLite paste model backend
@@ -74,6 +78,10 @@ class Paste(object):
 
         return paste.init(self.connection)
 
+    def sanitize(self):
+
+        return paste.sanitize(self.connection, self.model_class)
+
 
 def get_connection(parameters: Parameters):
     """get an sqlite connection object
diff --git a/src/httpaste/backend/sqlite/paste.py b/src/httpaste/backend/sqlite/paste.py
index 61f8cd1..bb0eb17 100644
--- a/src/httpaste/backend/sqlite/paste.py
+++ b/src/httpaste/backend/sqlite/paste.py
@@ -2,6 +2,7 @@
 """
 from os import path
 from sqlite3 import Connection
+from time import time
 
 
 def load(proto: object, connection: Connection, model_class: type):
@@ -11,7 +12,7 @@ def load(proto: object, connection: Connection, model_class: type):
     cur = connection.cursor()
 
     cur.execute(
-        'SELECT pid, data, data_hash, sub, timestamp, lifetime, encoding FROM pastes WHERE pid=?',
+        'SELECT pid, data, data_hash, sub, expiration, encoding FROM pastes WHERE pid=?',
         (proto.pid,
          ))
 
@@ -24,8 +25,7 @@ def load(proto: object, connection: Connection, model_class: type):
             result['sub'],
             result['data'],
             result['data_hash'],
-            result['timestamp'],
-            result['lifetime'],
+            result['expiration'],
             result['encoding'])
 
     return None
@@ -38,14 +38,13 @@ def dump(model: object, connection: Connection):
     cur = connection.cursor()
 
     cur.execute(
-        '''INSERT INTO pastes (pid, data, data_hash, sub, timestamp, lifetime, encoding)
-                   VALUES (?,?,?,?,?,?,?)''',
+        '''INSERT INTO pastes (pid, data, data_hash, sub, expiration, encoding)
+                   VALUES (?,?,?,?,?,?)''',
         (model.pid,
          model.data,
          model.data_hash,
          model.sub,
-         model.timestamp,
-         model.lifetime,
+         model.expiration,
          model.encoding))
 
     connection.commit()
@@ -69,3 +68,14 @@ def init(connection: Connection):
         cur.execute(fh.read())
 
     connection.commit()
+
+
+def sanitize(connection: Connection, model_class: type) -> bool:
+
+    cur = connection.cursor()
+
+    cur.execute('''SELECT pid FROM pastes WHERE expiration < ? AND expiration > 0''', (int(time()),))
+
+    for row in cur.fetchall():
+
+        delete(model_class(row['pid']))
\ No newline at end of file
diff --git a/src/httpaste/backend/sqlite/paste.sql b/src/httpaste/backend/sqlite/paste.sql
index 5788d5b..7f9bb46 100644
--- a/src/httpaste/backend/sqlite/paste.sql
+++ b/src/httpaste/backend/sqlite/paste.sql
@@ -1,10 +1,9 @@
 CREATE TABLE IF NOT EXISTS "pastes" (
-	"id"	BLOB NOT NULL UNIQUE,
+	"pid"	BLOB NOT NULL UNIQUE,
 	"data"	BLOB NOT NULL,
 	"data_hash"	BLOB NOT NULL,
 	"sub"	BLOB UNIQUE,
-	"timestamp"	INTEGER NOT NULL,
-	"lifetime"	INTEGER NOT NULL,
-    "encoding" TEXT
-	PRIMARY KEY("id")
+	"expiration"	INTEGER NOT NULL,
+	"encoding" TEXT,
+	PRIMARY KEY("pid")
 );
\ No newline at end of file
diff --git a/src/httpaste/backend/sqlite/user.py b/src/httpaste/backend/sqlite/user.py
index 423b797..11fc53e 100644
--- a/src/httpaste/backend/sqlite/user.py
+++ b/src/httpaste/backend/sqlite/user.py
@@ -53,3 +53,8 @@ def init(connection: Connection):
         cur.execute(fh.read())
 
     connection.commit()
+
+
+def sanitize(connection: Connection, model_class) -> bool:
+
+    return None
\ No newline at end of file
diff --git a/src/httpaste/controller/paste/__init__.py b/src/httpaste/controller/paste/__init__.py
index fcd6ab6..c8f4b87 100644
--- a/src/httpaste/controller/paste/__init__.py
+++ b/src/httpaste/controller/paste/__init__.py
@@ -71,7 +71,7 @@ def get(**kwargs):
                                            config.salt, config.hmac_iterations)
 
     try:
-        data, lifetime, encoding = call()
+        data, expiration, encoding = call()
     except paste_model.LifetimeError as e:
         if kwargs.get('user') is not None:
             paste_model.remove_safe(pid, sub, pkey, config.backend.paste, 
@@ -85,7 +85,7 @@ def get(**kwargs):
         raise ForbiddenError(str(e))
 
     # burn after read
-    if lifetime < 0:
+    if expiration < 0:
         if kwargs.get('user') is not None:
             paste_model.remove_safe(pid, sub, pkey, config.backend.paste, 
                                     config.salt, config.hmac_iterations)
diff --git a/src/httpaste/model/__init__.py b/src/httpaste/model/__init__.py
index 955ded4..7d1280f 100644
--- a/src/httpaste/model/__init__.py
+++ b/src/httpaste/model/__init__.py
@@ -1,6 +1,6 @@
 """Model
 """
-from typing import NamedTuple, Optional, Dict, Union
+from typing import NamedTuple, Optional, Dict, Union, Any, TypedDict
 
 
 class PasteDataSchema:
@@ -12,6 +12,7 @@ class PasteDataSchema:
     sub = bytes
     timestamp = int
     lifetime = int
+    expiration = int
     encoding = str
 
 
@@ -54,6 +55,14 @@ class PasteEncoding(PasteDataSchema.encoding):
     """
 
 
+class PasteExpiration(PasteDataSchema.expiration):
+    """Paste Expiration
+
+        < 0: after first acccess
+        0: never
+    """
+
+
 class PasteLifetime(PasteDataSchema.lifetime):
     """Paste Lifetime
     """
@@ -89,9 +98,11 @@ class Sub(UserDataSchema.sub):
     """
 
 
-class Index(Dict[PasteId, PasteKey]):
+class Index(TypedDict):
     """User Paste Index
     """
+    auth_expires: int
+    pastes: Dict[str, Dict[str, Any]]
 
 
 class SerializedIndex(UserDataSchema.index):
@@ -128,8 +139,6 @@ class Paste(NamedTuple):
     #: paste data hash
     data_hash: Optional[PasteHash] = None
     #: paste timestamp
-    timestamp: Optional[PasteTimestamp] = None
-    #: paste lifetime
-    lifetime: Optional[PasteLifetime] = None
+    expiration: Optional[PasteExpiration] = None
     #: paste encoding
     encoding: Optional[PasteEncoding] = None
diff --git a/src/httpaste/model/paste.py b/src/httpaste/model/paste.py
index 5ad9dc8..f7f856d 100755
--- a/src/httpaste/model/paste.py
+++ b/src/httpaste/model/paste.py
@@ -10,7 +10,7 @@ from httpaste.helper.crypto import dhash, shash, encrypt, decrypt
 from httpaste.helper.common import generate_random_string
 from httpaste.model import (Paste, PasteId, Sub, MasterKey, PasteKey, Salt,
                             PasteData, PasteHash, PasteTimestamp, PasteSub,
-                            PasteLifetime, PasteEncoding)
+                            PasteLifetime, PasteEncoding, PasteExpiration)
 
 
 class NotFoundError(Exception):
@@ -87,8 +87,7 @@ def load(proto: Paste, backend: object) -> Optional[Paste]:
 
         raise SubError('Paste not owned by user')
 
-    if model.lifetime >= 0 and model.timestamp + \
-            (60 * model.lifetime) < int(time.time()):
+    if model.expiration > 0 and model.expiration < int(time.time()):
 
         raise LifetimeError('Paste expired')
 
@@ -121,8 +120,7 @@ def load_safe(
         proto.sub,
         data,
         model.data_hash,
-        model.timestamp,
-        model.lifetime,
+        model.expiration,
         model.encoding)
 
 
@@ -195,6 +193,11 @@ def create(
     sub = None
     timestamp = PasteTimestamp(int(time.time()))
 
+    if lifetime < 0:
+        expiration = -1
+    else:
+        expiration = PasteExpiration(timestamp + (lifetime * 60))
+
     safe_data = PasteData(encrypt(data, pid, salt, hmac_iter))
 
     model = Paste(
@@ -202,8 +205,7 @@ def create(
         sub,
         safe_data,
         data_hash,
-        timestamp,
-        lifetime,
+        expiration,
         encoding)
 
     dump(model, backend)
@@ -234,6 +236,11 @@ def create_safe(data: PasteData,
     safe_sub = PasteSub(shash(sub, data_hash, pid))
     timestamp = PasteTimestamp(int(time.time()))
 
+    if lifetime < 0:
+        expiration = -1
+    else:
+        expiration = PasteExpiration(timestamp + (lifetime * 60))
+
     safe_data = PasteData(encrypt(data, pkey, salt, hmac_iter))
 
     dump(Paste(
@@ -241,8 +248,7 @@ def create_safe(data: PasteData,
         safe_sub,
         safe_data,
         data_hash,
-        timestamp,
-        lifetime,
+        expiration,
         encoding
     ), backend)
 
@@ -279,7 +285,7 @@ def get(pid: PasteId, backend: object, salt: Salt = Config.salt, hmac_iter: int
 
     data = decrypt(model.data, pid, salt, hmac_iter)
 
-    return PasteData(data), model.lifetime, model.encoding
+    return PasteData(data), model.expiration, model.encoding
 
 
 def get_safe(
@@ -294,4 +300,4 @@ def get_safe(
 
     model = load_safe(Paste(pid, sub), pkey, backend, salt, hmac_iter)
 
-    return PasteData(model.data), model.lifetime, model.encoding
+    return PasteData(model.data), model.expiration, model.encoding
diff --git a/src/httpaste/model/user.py b/src/httpaste/model/user.py
index 7639127..b925063 100755
--- a/src/httpaste/model/user.py
+++ b/src/httpaste/model/user.py
@@ -2,6 +2,7 @@
 """user model interface
 """
 import json
+from time import time
 from typing import Optional
 
 from httpaste import Config
@@ -34,7 +35,7 @@ class IndexError(Exception):
     """
 
 
-def load(
+def _load(
         proto: User,
         master_key: str,
         backend: object,
@@ -54,16 +55,19 @@ def load(
         return None
 
     try:
-        return User(
-            *model[:-1],
-            Index(**json.loads(decrypt(model.index, master_key, salt, hmac_iter)))
-        )
+        serialized_data = decrypt(model.index, master_key, salt, hmac_iter)
     except DecryptionError as e:
-
         raise IndexError('unable to decrypt user index') from e
+    else:
+        data = json.loads(serialized_data)
+
+    return User(
+        *model[:-1],
+        Index(**data)
+    )
 
 
-def dump(
+def _dump(
         model: User,
         key: MasterKey,
         backend: object,
@@ -77,7 +81,7 @@ def dump(
         :param salt: randomization salt
     """
 
-    if not isinstance(model.index, Index):
+    if model.index is not None and not isinstance(model.index, dict):
 
         raise BaseException('index serialization pre-processing not allowed.')
 
@@ -102,11 +106,13 @@ def load_paste_key(
         :param salt: randomization salt
     """
 
-    for k, v in load(User(sub), key, backend, salt, hmac_iter).index.items():
+    model = _load(User(sub), key, backend, salt, hmac_iter)
+
+    for k, v in model.index.get('pastes').items():
 
         if bytes.fromhex(k) == pid:
 
-            return PasteKey(bytes.fromhex(v))
+            return PasteKey(bytes.fromhex(v.get('key')))
 
     return None
 
@@ -128,12 +134,13 @@ def dump_paste_key(
         :param backend: user model backend
     """
 
-    model = load(User(sub), key, backend, salt, hmac_iter)
+    model = _load(User(sub), key, backend, salt, hmac_iter)
 
-    dump(User(*model[:-1], Index({
-        **model.index,
-        **{pid.hex(): pkey.hex()}
-    })), key, backend, salt, hmac_iter)
+    model.index.setdefault('pastes', {})[pid.hex()] = {
+        'key': pkey.hex()
+    }
+
+    _dump(model, key, backend, salt, hmac_iter)
 
 
 def authenticate(
@@ -154,22 +161,36 @@ def authenticate(
 
     proto = User(sub)
 
+    bogus_decline_msg = 'unable to authenticate'
+
     try:
-        model = load(proto, key, backend, salt, hmac_iter)
+        model = _load(proto, key, backend, salt, hmac_iter)
     except IndexError as e:
-        raise AuthenticationError('you dun goofed')
+        raise AuthenticationError(bogus_decline_msg) from e
 
     if not model:
 
-        model = User(sub, key_hash, Index({}))
-        dump(model, key, backend, salt, hmac_iter)
+        data = {
+            'auth_expires': int(time()) + (1 * 60)
+        }
+
+        model = User(sub, key_hash, Index(data))
+        _dump(model, key, backend, salt, hmac_iter)
     else:
 
         if model.key_hash != key_hash:
 
-            raise AuthenticationError('you dun goofed')
+            raise AuthenticationError(bogus_decline_msg)
 
     return {
         'sub': sub,
         'master_key': key
     }
+
+
+__all__ = [
+    AuthenticationError,
+    load_paste_key,
+    dump_paste_key,
+    authenticate
+]
\ No newline at end of file