app.py

"""A gradio app for credit card approval prediction using FHE."""

import subprocess
import time
import gradio as gr

from settings import (
    REPO_DIR,
    ACCOUNT_MIN_MAX,
    CHILDREN_MIN_MAX,
    INCOME_MIN_MAX,
    AGE_MIN_MAX,
    SALARIED_MIN_MAX,
    FAMILY_MIN_MAX,
    INCOME_TYPES,
    OCCUPATION_TYPES,
    HOUSING_TYPES,
    EDUCATION_TYPES,
    FAMILY_STATUS,
)
from backend import (
    keygen_send,
    pre_process_encrypt_send_user,
    pre_process_encrypt_send_bank,
    pre_process_encrypt_send_third_party,
    run_fhe,
    get_output,
    decrypt_output,
)


subprocess.Popen(["uvicorn", "server:app"], cwd=REPO_DIR)
time.sleep(3)


demo = gr.Blocks()


print("Starting the demo...")
with demo:
    gr.Markdown(
        """
        <h1 align="center">Encrypted Credit Card Approval Prediction Using Fully Homomorphic Encryption</h1>
        """
    )

    gr.Markdown("# Client side")

    gr.Markdown("## Step 1: Generate the keys.")
    gr.Markdown(
        """
        - The private key is used to encrypt and decrypt the data and shall never be shared.
        - The evaluation key is a public key that the server needs to process encrypted data. It is
        therefore transmitted to the server for further processing as well.
        """
    )
    keygen_button = gr.Button("Generate the keys and send evaluation key to the server.")
    evaluation_key = gr.Textbox(
        label="Evaluation key representation:", max_lines=2, interactive=False
    )
    client_id = gr.Textbox(label="", max_lines=2, interactive=False, visible=False)
    
    gr.Markdown("## Step 2: Fill in some information.")
    gr.Markdown(
        """
        Select any information that corresponds to the profile you want to evaluate. Three
        dissociated parties are represented :
        - the user, which provides some personal information in order to evaluate its credit card 
        eligibility 
        - the user's bank, which provides any of the user's banking information relevant to the 
        decision
        - a third party, which represents any other party (here, the user's employer) that could 
        provide any information relevant to the decision
        """
    )

    with gr.Row():
        with gr.Column():
            gr.Markdown("### User")
            bool_inputs = gr.CheckboxGroup(["Car", "Property", "Work phone", "Phone", "Email"], label="What do you own ?")
            num_children = gr.Slider(**CHILDREN_MIN_MAX, step=1, label="Number of children", info="How many children do you have ?")
            household_size = gr.Slider(**FAMILY_MIN_MAX, step=1, label="Household size", info="How many members does your household have? ?")
            total_income = gr.Slider(**INCOME_MIN_MAX, label="Income", info="What's you total yearly income (in euros) ?")
            age = gr.Slider(**AGE_MIN_MAX, step=1, label="Age", info="How old are you ?")
            income_type = gr.Dropdown(choices=INCOME_TYPES, value=INCOME_TYPES[0], label="Income type", info="What is your main type of income ?")
            education_type = gr.Dropdown(choices=EDUCATION_TYPES, value=EDUCATION_TYPES[0], label="Education", info="What is your education background ?")
            family_status = gr.Dropdown(choices=FAMILY_STATUS, value=FAMILY_STATUS[0], label="Family", info="What is your family status ?")
            occupation_type = gr.Dropdown(choices=OCCUPATION_TYPES, value=OCCUPATION_TYPES[0], label="Occupation", info="What is your main occupation ?")
            housing_type = gr.Dropdown(choices=HOUSING_TYPES, value=HOUSING_TYPES[0], label="Housing", info="In what type of housing do you live ?")

        with gr.Column():
            gr.Markdown("### Bank ")
            account_age = gr.Slider(**ACCOUNT_MIN_MAX, step=1, label="Account age (months)", info="How long have this person had this bank account (in months) ?")

        with gr.Column():
            gr.Markdown("### Third party ")
            salaried = gr.Radio(["Yes", "No"], label="Is the person salaried ?", value="Yes")
            years_salaried = gr.Slider(**SALARIED_MIN_MAX, step=1, label="Years of employment", info="How long have this person been salaried (in years) ?")


    gr.Markdown("## Step 3: Encrypt the inputs using FHE and send them to the server.")
    with gr.Row():
        with gr.Column():
            gr.Markdown("### User")
            encrypt_button_user = gr.Button("Encrypt the inputs and send to server.")
            
            encrypted_input_user = gr.Textbox(
                label="Encrypted input representation:", max_lines=2, interactive=False
            )


        with gr.Column():
            gr.Markdown("### Bank ")
            encrypt_button_bank = gr.Button("Encrypt the inputs and send to server.")

            encrypted_input_bank = gr.Textbox(
                label="Encrypted input representation:", max_lines=2, interactive=False
            )


        with gr.Column():
            gr.Markdown("### Third Party ")
            encrypt_button_third_party = gr.Button("Encrypt the inputs and send to server.")

            encrypted_input_third_party = gr.Textbox(
                label="Encrypted input representation:", max_lines=2, interactive=False
            )

    gr.Markdown("# Server side")
    gr.Markdown(
        """
        Once the server receives the encrypted inputs, it can compute the prediction without ever 
        needing to decrypt any value.

        This server employs an [XGBoost](https://github.com/dmlc/xgboost) classifier model that has 
        been trained on [this credit card data-set](https://www.kaggle.com/datasets/rikdifos/credit-card-approval-prediction/data).
        """
    )

    gr.Markdown("## Step 4: Run FHE execution.")
    execute_fhe_button = gr.Button("Run FHE execution.")
    fhe_execution_time = gr.Textbox(
        label="Total FHE execution time (in seconds):", max_lines=1, interactive=False
    )

    gr.Markdown("# Client side")  
    gr.Markdown(
        """
        Once the server completed the inference, the encrypted output is returned to the user.
        """
    )

    gr.Markdown("## Step 5: Receive the encrypted output from the server.")
    gr.Markdown(
        """
        The value displayed below is a shortened byte representation of the actual encrypted output.
        """
    )

    get_output_button = gr.Button("Receive the encrypted output from the server.")
    encrypted_output_representation = gr.Textbox(
        label="Encrypted output representation: ", max_lines=2, interactive=False
    )

    gr.Markdown("## Step 6: Decrypt the output.")
    gr.Markdown(
        """
        The user is able to decrypt the prediction using its private key.
        """
    )

    decrypt_button = gr.Button("Decrypt the output")
    prediction_output = gr.Textbox(
        label="Prediction", max_lines=1, interactive=False
    )

    # Button generate the keys
    keygen_button.click(
        keygen_send,
        outputs=[client_id, evaluation_key, keygen_button],
    )

    # Button to pre-process, generate the key, encrypt and send the user inputs from the client 
    # side to the server
    encrypt_button_user.click(
        pre_process_encrypt_send_user,
        inputs=[client_id, bool_inputs, num_children, household_size, total_income, age, \
                income_type, education_type, family_status, occupation_type, housing_type],
        outputs=[encrypted_input_user],
    )

    # Button to pre-process, generate the key, encrypt and send the bank inputs from the client 
    # side to the server
    encrypt_button_bank.click(
        pre_process_encrypt_send_bank,
        inputs=[client_id, account_age],
        outputs=[encrypted_input_bank],
    )

    # Button to pre-process, generate the key, encrypt and send the third party inputs from the 
    # client side to the server    
    encrypt_button_third_party.click(
        pre_process_encrypt_send_third_party,
        inputs=[client_id, salaried, years_salaried],
        outputs=[encrypted_input_third_party],
    )

    # Button to send the encodings to the server using post method
    execute_fhe_button.click(run_fhe, inputs=[client_id], outputs=[fhe_execution_time])

    # Button to send the encodings to the server using post method
    get_output_button.click(
        get_output, 
        inputs=[client_id], 
        outputs=[encrypted_output_representation],
    )

    # Button to decrypt the output
    decrypt_button.click(
        decrypt_output,
        inputs=[client_id],
        outputs=[prediction_output],
    )

    gr.Markdown(
        "The app was built with [Concrete-ML](https://github.com/zama-ai/concrete-ml), a "
        "Privacy-Preserving Machine Learning (PPML) open-source set of tools by [Zama](https://zama.ai/). "
        "Try it yourself and don't forget to star on Github &#11088;."
    )

demo.launch(share=False)