Encryption & Cryptography

scripts/page1.ts
import Page1Design from 'generated/pages/page1';
import Crypto from 'sf-core/global/crypto';
import Data from 'sf-core/global/data';
import System from 'sf-core/device/system';
import Label from 'sf-core/ui/label';
import Button from 'sf-core/ui/button';
import FlexLayout from 'sf-core/ui/flexlayout';
import TextBox from 'sf-core/ui/textbox';
​
const ENCRYPT_KEY_SIZE = 1024;
const ENCRYPT_CIPHER_TYPE = 'RSA/ECB/PKCS1Padding';
const PUBLIC_KEY_DEVICE_KEY = 'publicKey'; //The key to save to the device database
const PRIVATE_KEY_DEVICE_KEY = 'privateKey'; //The key to save to the device database
​
export default class Page1 extends Page1Design {
    router: any;
    myLabel: Label;
    encryptButton: Button;
    decryptButton: Button;
    tbEncrypt: TextBox;
    private encryptedText = '';
    constructor() {
        super();
        this.onShow = onShow.bind(this, this.onShow.bind(this));
        this.onLoad = onLoad.bind(this, this.onLoad.bind(this));
        this.myLabel = new Label();
        this.encryptButton = new Button();
        this.decryptButton = new Button();
        this.tbEncrypt = new TextBox();
    }
​
    generateKeyPair() {
        let privateKey = Data.getStringVariable(PRIVATE_KEY_DEVICE_KEY);
        let publicKey = Data.getStringVariable(PUBLIC_KEY_DEVICE_KEY);
        if (!privateKey || !publicKey) {
            const didGenerate = Crypto.generateKeyPair({
                keySize: ENCRYPT_KEY_SIZE
            });
            if (!didGenerate) {
                return 'Could not generate keypair';
            }
            privateKey = Crypto.getBase64PrivateString();
            publicKey = Crypto.getBase64PublicString();
            Data.setStringVariable(PUBLIC_KEY_DEVICE_KEY, publicKey); // Public key doesn't need to be stored securely
            Data.setStringVariable(PRIVATE_KEY_DEVICE_KEY, privateKey); // Consider using secure data
        }
        else {
            // Set pre-stored keys if there is already one
            Crypto.setPrivateKey(privateKey);
            Crypto.setPublicKey(publicKey);
        }
        return {
            private: privateKey,
            public: System.OS === 'iOS' ? Crypto.ios.getExportedPublicKey() : publicKey,
        };
    }
​
    encrypt(text: string): string {
        const keyBody = {
            text: 'Smartface Inc.',
            secretText: text
        };
        return Crypto.encrypt({
            useServerKey: false,
            cipherType: ENCRYPT_CIPHER_TYPE,
            plainText: JSON.stringify(keyBody)
        });
    }
​
    decrypt(encryptedText: string): string {
        return Crypto.decrypt({
            encryptedText: encryptedText,
            useServerKey: false,
            cipherType: ENCRYPT_CIPHER_TYPE
        });
    }
​
    initLabel() {
        this.myLabel.text = 'Decrpyted text will go here';
        //@ts-ignore
        this.layout.addChild(this.myLabel, 'myLabel', '.sf-label');
    }
​
    initButtons() {
        const buttonWrapper = new FlexLayout();
        //@ts-ignore
        this.layout.addChild(buttonWrapper, 'buttonWrapper', '.sf-flexlayout', {
            heigth: 120
        });
        this.encryptButton.text = 'Encrypt';
        this.encryptButton.onPress = () => {
            this.encryptedText = this.encrypt(this.tbEncrypt.text || '');
        };
        this.decryptButton.text = 'Decrypt';
        this.decryptButton.onPress = () => {
            const decryptedObjectText = this.decrypt(this.encryptedText);
            const decrpytedObject = JSON.parse(decryptedObjectText);
            this.myLabel.text = decrpytedObject.secretText;
        };
        //@ts-ignore
        buttonWrapper.addChild(this.encryptButton, 'encryptButton', '.sf-button');
        //@ts-ignore
        buttonWrapper.addChild(this.decryptButton, 'decryptButton', '.sf-button');
    }
​
    initTextBox() {
        this.tbEncrypt.hint = 'Enter text to encrypt';
        //@ts-ignore
        this.layout.addChild(this.tbEncrypt, 'tbEncrypt', '.sf-textbox');
    }
}
​
function onShow(superOnShow) {
    superOnShow();
}
​
function onLoad(superOnLoad) {
    superOnLoad();
    this.generateKeyPair();
    this.initTextBox();
    this.initLabel();
    this.initButtons();
    this.layout.applyLayout();
}