Synopsis

import ksi
import hashlib

# Instantiate service parameters from the environment
KSI = ksi.KSI(**ksi.ksi_env())

# Sign a text string
sig = KSI.sign_hash(hashlib.sha256(b"Tere!"))
# Print some signature properties
print(sig.get_signing_time(), sig.get_signer_id())

# Now verify this text string, first obtaining a data hasher
h = sig.get_hasher()
h.update(b"Tere!")
print(KSI.verify_hash(sig, h))

# Obtain a binary blob which can be stored for long term
serialized_signature = sig.serialize()

# Some time have passed, fetch the signature and verify again
sig2 = KSI.parse(serialized_signature)
KSI.set_verification_policy(KSI.verification.POLICY_CALENDAR_BASED)
print(KSI.verify_hash(sig2, h))

Install

1. Requirements: Python 2.7+ or Python 3.1+. Jython, IronPython do not work.

2. Install fresh libksi aka KSI C SDK; see https://github.com/guardtime/libksi/

3. Install python-devel package

4. Run:

   > pip install ksi-python

or

> easy_install ksi-python

Tests

Specify KSI Gateway access parameters and run

> python setup.py test

Documentation

http://guardtime.github.io/ksi-python/

Type:

> pydoc ksi

to read the documentation after installation. Generating html or pdf documentation: make sure that dependencies like sphinx (pip install sphinx) are installed and run:

> cd docs
> make html
> make latexpdf

Limitations

• Synchronous calls–especially signing–block green threads.

• Advanced functions like block signing, containers, async operations, are not implemented.

• Python’s __del__ destructor is not guaranteed to execute. Please help garbage collector by dereferencing unnecessary signature objects with del.

License

Apache 2.0. Please contact Guardtime for supported options.