README.txt

# Example using libnacl based encryption engine

(venv)[gm@localhost libnacl]$ python demo.py
username = fred, password = secret
username = mary, password = secret
(venv)[gm@localhost libnacl]$ sqlite3 /tmp/demo.db  'select * from user;'
1|fred|b2997d0bf6634b6472881f7c40dab2f5e880f03fdeca340aea977500441479ed04637fae0d5f49bd0c9ab4bdcd9a
2|mary|abb99fe819e861b105eae670741360cf3a51e414a0670d87e20432166bafa859d4733092c14a602fb76f58264fb6
(venv)[gm@localhost libnacl]$ pip freeze
You are using pip version 6.0.8, however version 8.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
cffi==1.5.0
cryptography==1.2.1
enum34==1.1.2
idna==2.0
ipaddress==1.0.16
libnacl==1.4.4
pyasn1==0.1.9
pycparser==2.14
six==1.10.0
SQLAlchemy==1.0.11
SQLAlchemy-Utils==0.31.6

demo.py

import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy_utils import EncryptedType
from sqlalchemy_utils.types.encrypted import EncryptionDecryptionBaseEngine 

from libnacl.secret import SecretBox


class NaclEngine(EncryptionDecryptionBaseEngine):
    
    def _initialize_engine(self, parent_key_class):
        self.secret_key = parent_key_class

    def encrypt(self, value):
        return SecretBox(key=self.secret_key).encrypt(value).encode('hex')

    def decrypt(self, value):
        return SecretBox(key=self.secret_key).decrypt(value.decode('hex'))


secret_key = 'secretkey1234'
# setup
#engine = create_engine('sqlite:///:memory:')
engine = create_engine('sqlite:////tmp/demo.db')
connection = engine.connect()
Base = declarative_base()

class User(Base):
    __tablename__ = "user"
    id = sa.Column(sa.Integer, primary_key=True)
    username = sa.Column(sa.String())
    password = sa.Column(EncryptedType(sa.String, secret_key, engine=NaclEngine))

sa.orm.configure_mappers()
Base.metadata.create_all(connection)

# create a configured "Session" class
Session = sessionmaker(bind=connection)

# create a Session
session = Session()

# example
fred = User(username='fred', password='secret')
session.add(fred)
session.commit()

mary = User(username='mary', password='secret')
session.add(mary)
session.commit()

for user in session.query(User).all():
    print("username = {}, password = {}".format(user.username, user.password))


# teardown
session.close_all()
#Base.metadata.drop_all(connection)
connection.close()
engine.dispose()