.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "_autoexamples/Demo_WAHC21.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download__autoexamples_Demo_WAHC21.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr__autoexamples_Demo_WAHC21.py:


WAHC21
===========================

This demo includes all the code snippets from the WAHC21 Pyfhel paper (corresponding sections in parenthesis).

.. GENERATED FROM PYTHON SOURCE LINES 8-17

1. Setup and Parameters (Sec. 4.1)
-----------------------------------------------------
We start by importing the library with the three main classes:
* Pyfhel class contains most of the functions.
* PyPtxt is the plaintext class
* PyCtxt is the ciphertext class

Then we generate a context a context and a public/secret key pair.
 -> This is all managed by a Pyfhel instance under the hood. 

.. GENERATED FROM PYTHON SOURCE LINES 17-29

.. code-block:: Python

    from Pyfhel import Pyfhel, PyPtxt, PyCtxt

    HE = Pyfhel()           # Creating empty Pyfhel object
    HE.contextGen(scheme='BFV', n=4096, t_bits=20, sec=128)  # Generating context. The p defines the plaintext modulo.
                            #  There are many configurable parameters on this step
                            #  More info in Demo_ContextParameters, and
                            #  in Pyfhel.contextGen()
    HE.keyGen()             # Key Generation: generates a pair of public/secret keys
    print("-----------------------------------------------------")
    print("1. Setup: ", HE)






.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    -----------------------------------------------------
    1. Setup:  <bfv Pyfhel obj at 0x7fecac57d710, [pk:Y, sk:Y, rtk:-, rlk:-, contx(n=4096, t=1032193, sec=128, qi=[], scale=1.0, )]>




.. GENERATED FROM PYTHON SOURCE LINES 30-33

2. Encryption & Decryption (Sec. 4.2)
-----------------------------------------------------
We show how to encrypt and decrypt a plaintex, including encoding and decoding.

.. GENERATED FROM PYTHON SOURCE LINES 33-53

.. code-block:: Python

    integer = 45 
    int_ptxt = HE.encode(integer)   # PyPtxt [45, 45,...]
    int_ctxt = HE.encrypt(int_ptxt) # PyCtxt

    import numpy as np
    np_array = np.array([6, 5, 4, 3, 2, 1],dtype=np.int64)
    array_ptxt = HE.encode(np_array)    # Accepts list too
    array_ctxt = HE.encrypt(array_ptxt) # PyCtxt

    # Decrypt and Decode
    ptxt_dec = HE.decrypt(int_ctxt, decode=False)   # PyPtxt
    integer_dec = HE.decode(ptxt_dec) # integer
    print("-----------------------------------------------------")
    print("2. Encryption & Decryption: ")
    print("Encrypting integer: ", integer, " -> ", int_ptxt , " -> ", int_ctxt)
    print("Decrypting integer: ", int_ctxt, " -> ", ptxt_dec, " -> ", integer_dec[:3],"...")








.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    -----------------------------------------------------
    2. Encryption & Decryption: 
    Encrypting integer:  45  ->  <Pyfhel Plaintext at 0x7fecac56e300, scheme=bfv, poly=2D, is_ntt=->  ->  <Pyfhel Ciphertext at 0x7fecac120860, scheme=bfv, size=2/2, noiseBudget=45>
    Decrypting integer:  <Pyfhel Ciphertext at 0x7fecac120860, scheme=bfv, size=2/2, noiseBudget=45>  ->  <Pyfhel Plaintext at 0x7fecac56e340, scheme=bfv, poly=2D, is_ntt=->  ->  [45 45 45] ...




.. GENERATED FROM PYTHON SOURCE LINES 54-57

3. Homomorphic Operations (Sec. 4.3)
-----------------------------------------------------
we will define two integers, encrypt them and operate:

.. GENERATED FROM PYTHON SOURCE LINES 57-81

.. code-block:: Python

    ptxt_a = HE.encode(-12)
    ptxt_b = HE.encode(34)
    ctxt_a = HE.encrypt(56)
    ctxt_b = HE.encrypt(-78)

    # ctxt-ctxt operations
    ctxt_s = ctxt_a + ctxt_b # or ctxt_a += ctxt_b (in place)
    ctxt_m = ctxt_a * ctxt_b

    # ctxt-ptxt operations
    ctxt_s_p = ptxt_a + ctxt_b # or 12 + ctxt_b
    ctxt_m_p = ctxt_a * ptxt_b # or ctxt_a * 34

    # maintenance operations
    HE.relinKeyGen()        # bfv only
    HE.relinearize(ctxt_s)  # requires relinKey
    HE.rotateKeyGen()
    # HE.rescale_to_next(ctxt_r) # ckks only

    # rotations (length n)
    ctxt_c = HE.encrypt([1,2,3,4])
    ctxt_rotated = ctxt_c << 1 # [2,3,4,0,...,0,1









.. GENERATED FROM PYTHON SOURCE LINES 82-84

4. IO & Serialization (Sec. 4.4)
-----------------------------------------------------

.. GENERATED FROM PYTHON SOURCE LINES 84-120

.. code-block:: Python

    import os # to cleanup files

    ##### CLIENT
    HE = Pyfhel()
    HE.contextGen(scheme='BFV', n=4096, t_bits=0, t=65537, sec=128)
    HE.keyGen() # Generates public and private key
    # Save context and public key only
    HE.save_public_key("mypk.pk")
    HE.save_context("mycontext.con")
    # Encrypt and save inputs
    ctxt_a = HE.encrypt(15) # implicit encoding
    ctxt_b = HE.encrypt(25)
    ctxt_a.save("ctxt_a.ctxt")
    ctxt_b.save("ctxt_b.ctxt")

    ##### SERVER
    HE_server = Pyfhel()    
    HE_server.load_context("mycontext.con")
    HE_server.load_public_key("mypk.pk") # no secret key
    # Load ciphertexts
    ca = PyCtxt(pyfhel=HE_server, fileName="ctxt_a.ctxt")
    cb = PyCtxt(pyfhel=HE_server, fileName="ctxt_b.ctxt")
    # Compute homomorphically and send result
    cr = (ca + cb) * 2
    cr.save("cr.ctxt")

    ##### CLIENT 
    # Load and decrypt result
    c_res = PyCtxt(pyfhel=HE, fileName="cr.ctxt")
    print("-----------------------------------------------------")
    print("Client_server result:", c_res.decrypt())
    for f in ["mypk.pk", "mycontext.con", "ctxt_a.ctxt", "ctxt_b.ctxt", "cr.ctxt"]:
        os.remove(f)







.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    -----------------------------------------------------
    Client_server result: [80 80 80 ... 80 80 80]




.. GENERATED FROM PYTHON SOURCE LINES 121-123

5. Exploring CKKS pitfalls (Sec. 5.1)
-----------------------------------------------------

.. GENERATED FROM PYTHON SOURCE LINES 123-160

.. code-block:: Python

    print("-----------------------------------------------------")
    from Pyfhel import PyCtxt, Pyfhel, PyPtxt
    HE = Pyfhel()
    HE.contextGen(scheme='CKKS', n=16384, qi_sizes=[30,30,30,30,30], scale=2 ** 30)
    HE.keyGen()
    ctxt_x = HE.encrypt(3.1, scale=2 ** 30) # implicit encode
    ctxt_y = HE.encrypt(4.1, scale=2 ** 30)
    ctxt_z = HE.encrypt(5.9, scale=2 ** 30)

    ctxtSum = HE.add(ctxt_x, ctxt_y)
    ctxtProd = HE.multiply_plain(ctxt_z, HE.encode(5))
    ctxt_t = HE.multiply(ctxtSum, ctxtProd)

    ptxt_ten = HE.encode(10, scale=2 ** 30)
    try:
        ctxt_result = HE.add_plain(ctxt_t, ptxt_ten) #error: mismatched scales
    except ValueError as e:
        assert str(e) == "scale mismatch"
        print("CKKS: Mismatched scales detected!")
    
    ptxt_d = HE.encode(10, 2 ** 30)
    ctxt_d = HE.encrypt(ptxt_d)
    HE.rescale_to_next(ctxt_t)  # 2^90 -> 2^60
    HE.rescale_to_next(ctxt_t)  # 2^60 -> 2^30

    HE.mod_switch_to_next(ctxt_d) # match first rescale
    HE.mod_switch_to_next(ctxt_d) # match second rescale

    ctxt_t.set_scale(2**30)
    ctxt_result = HE.add(ctxt_t, ctxt_d) # final result

    # NOTE: The original code (substituting `HE.multiply` and  `HE.add`
    #  by `+` and `*`) no longer generates an error: scales are 
    #  automatically aligned using HE.align_mod_n_scale when using 
    #  operator overloads `+`, `-`, `*` and `/`.






.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    -----------------------------------------------------
    CKKS: Mismatched scales detected!




.. GENERATED FROM PYTHON SOURCE LINES 161-164

6. Implementing Key-Recovery for CKKS (Sec. 5.2)
-----------------------------------------------------
Setup: Encrypt, Decrypt, Decode

.. GENERATED FROM PYTHON SOURCE LINES 164-176

.. code-block:: Python

    ctxt = HE.encrypt(0, scale=2**40)
    ptxt_dec = HE.decryptPtxt(ctxt)
    values = HE.decodeComplex(ptxt_dec)

    # Attack
    ptxt_re = HE.encode(values, scale=2**40)
    a = HE.poly_from_ciphertext(ctxt,1) # PyPoly
    b = HE.poly_from_ciphertext(ctxt,0) # or b = ctxt[0]
    m = HE.poly_from_plaintext(ctxt, ptxt_re) # PyPoly
    s = (m - b) * ~a # ~a = inverse of a
    print("-----------------------------------------------------")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    -----------------------------------------------------





.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 1.160 seconds)

**Estimated memory usage:**  27 MB


.. _sphx_glr_download__autoexamples_Demo_WAHC21.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: Demo_WAHC21.ipynb <Demo_WAHC21.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: Demo_WAHC21.py <Demo_WAHC21.py>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_