function submit() {
    var form = document.querySelector("form");
    var plainText = document.querySelector("input[name=ip]").value;

    var fileInput = document.createElement('input');
    fileInput.type = 'file';

    fileInput.addEventListener('change', function (e) {
        var file = e.target.files[0];
        var reader = new FileReader();

        reader.onloadend = function (e) {
            var privateKey = e.target.result;

            var encryptor = new JSEncrypt();
            encryptor.setPrivateKey(privateKey);
            var signedText = encryptor.sign(plainText, SHA256, "sha256");

            const params = new URLSearchParams();
            params.append('token', signedText);

            fetch(form.action, {
                method: form.method,
                headers: {
                    'Content-Type': 'application/x-www-form-urlencoded'
                },
                body: params
            })
            .then(response => {
                var main = document.querySelector("main");
                var p = document.createElement("h1");
                p.textContent = response.text();
                main.appendChild(p);
                //window.location.href = "http://localhost/inbox/home";
            })
            .catch(error => {
                var main = document.querySelector("main");
                var p = document.createElement("h1");
                p.textContent = error.text();
                main.appendChild(p);
            });
        };

        reader.readAsText(file);
    });

    fileInput.click();
}

function SHA256(string) {
    function rotr(x, n) {
        return (x >>> n) | (x << (32 - n));
    }

    function sha256(message) {
        const words = [];
        let h0 = 0x6a09e667;
        let h1 = 0xbb67ae85;
        let h2 = 0x3c6ef372;
        let h3 = 0xa54ff53a;
        let h4 = 0x510e527f;
        let h5 = 0x9b05688c;
        let h6 = 0x1f83d9ab;
        let h7 = 0x5be0cd19;

        const k = [
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
        0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
        0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
        0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
        0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
        ];

        message += String.fromCharCode(0x80);
        const originalLength = message.length * 8;
        let paddingBytes = 64 - ((message.length + 8) % 64);
        paddingBytes = paddingBytes === 64 ? 0 : paddingBytes;

        for (let i = 0; i < paddingBytes; i++) {
            message += String.fromCharCode(0x00);
        }

        message += String.fromCharCode((originalLength >>> 56) & 0xff);
        message += String.fromCharCode((originalLength >>> 48) & 0xff);
        message += String.fromCharCode((originalLength >>> 40) & 0xff);
        message += String.fromCharCode((originalLength >>> 32) & 0xff);
        message += String.fromCharCode((originalLength >>> 24) & 0xff);
        message += String.fromCharCode((originalLength >>> 16) & 0xff);
        message += String.fromCharCode((originalLength >>> 8) & 0xff);
        message += String.fromCharCode(originalLength & 0xff);

        for (let i = 0; i < message.length; i += 64) {
            const chunk = message.slice(i, i + 64);
            const w = [];

            for (let j = 0; j < 16; j++) {
                w[j] = ((chunk.charCodeAt(j * 4) & 0xff) << 24) |
                ((chunk.charCodeAt(j * 4 + 1) & 0xff) << 16) |
                ((chunk.charCodeAt(j * 4 + 2) & 0xff) << 8) |
                (chunk.charCodeAt(j * 4 + 3) & 0xff);
            }

            for (let j = 16; j < 64; j++) {
                const s0 = rotr(w[j - 15], 7) ^ rotr(w[j - 15], 18) ^ (w[j - 15] >>> 3);
                const s1 = rotr(w[j - 2], 17) ^ rotr(w[j - 2], 19) ^ (w[j - 2] >>> 10);
                w[j] = (w[j - 16] + s0 + w[j - 7] + s1) & 0xffffffff;
            }

            let [a, b, c, d, e, f, g, h] = [h0, h1, h2, h3, h4, h5, h6, h7];

            for (let j = 0; j < 64; j++) {
                const s1 = rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25);
                const ch = (e & f) ^ (~e & g);
                const temp1 = (h + s1 + ch + k[j] + w[j]) & 0xffffffff;
                const s0 = rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22);
                const maj = (a & b) ^ (a & c) ^ (b & c);
                const temp2 = (s0 + maj) & 0xffffffff;

                h = g;
                g = f;
                f = e;
                e = (d + temp1) & 0xffffffff;
                d = c;
                c = b;
                b = a;
                a = (temp1 + temp2) & 0xffffffff;
            }

            h0 = (h0 + a) & 0xffffffff;
            h1 = (h1 + b) & 0xffffffff;
            h2 = (h2 + c) & 0xffffffff;
            h3 = (h3 + d) & 0xffffffff;
            h4 = (h4 + e) & 0xffffffff;
            h5 = (h5 + f) & 0xffffffff;
            h6 = (h6 + g) & 0xffffffff;
            h7 = (h7 + h) & 0xffffffff;
        }

        const hash = [
        (h0 >>> 24) & 0xff, (h0 >>> 16) & 0xff, (h0 >>> 8) & 0xff, h0 & 0xff,
        (h1 >>> 24) & 0xff, (h1 >>> 16) & 0xff, (h1 >>> 8) & 0xff, h1 & 0xff,
        (h2 >>> 24) & 0xff, (h2 >>> 16) & 0xff, (h2 >>> 8) & 0xff, h2 & 0xff,
        (h3 >>> 24) & 0xff, (h3 >>> 16) & 0xff, (h3 >>> 8) & 0xff, h3 & 0xff,
        (h4 >>> 24) & 0xff, (h4 >>> 16) & 0xff, (h4 >>> 8) & 0xff, h4 & 0xff,
        (h5 >>> 24) & 0xff, (h5 >>> 16) & 0xff, (h5 >>> 8) & 0xff, h5 & 0xff,
        (h6 >>> 24) & 0xff, (h6 >>> 16) & 0xff, (h6 >>> 8) & 0xff, h6 & 0xff,
        (h7 >>> 24) & 0xff, (h7 >>> 16) & 0xff, (h7 >>> 8) & 0xff, h7 & 0xff
        ];

        let hashHex = '';

        for (let i = 0; i < hash.length; i++) {
            const value = hash[i];
            const hex = (value < 16 ? '0' : '') + value.toString(16);
            hashHex += hex;
        }

        return hashHex;
    }

    return sha256(string);
}