Javascript easily encrypted text files but in the case of images it does not give me result I already tried with the input type readAsDataURL () and it is great how in the data output once decrypted it shows the connection in the correct url format that can be displayed in the browser but I don't know how to convert the string into a file

<script type="module"> /* file encryption/decryption */
    document.addEventListener('DOMContentLoaded', function(event) {
        document.getElementById('src-file').onchange = function() {
            const file = this.files[0];
            document.querySelector('#progress').removeAttribute('value');
            const t1 = performance.now();
            var reader = new FileReader();
            reader.readAsText(file, 'utf-8');
            reader.onload = function() {
            document.querySelector('#progress').value = 100;
            var password = document.querySelector('#password').value;
            var bits = 256;
            var plaintext = reader.result;
            var ciphertext = AesCtr.encrypt(plaintext, password, bits);
            var blob = new Blob([ciphertext], { type: 'text/plain' });
            saveAs(blob, file.name + '.enc');
            document.querySelector('#progress').value = 0;
            const t2 = performance.now();
            const t = ((t2-t1)/1000).toFixed(3)+'s';
            document.querySelector('#decrypt-file-time').textContent = t;
            }
}

        document.querySelector('#enc-file').onchange = function() {
            const file = this.files[0];
            document.querySelector('#progress').removeAttribute('value');
            const t1 = performance.now();
            var reader = new FileReader();
            reader.readAsText(file, 'iso-8859-1');
            reader.onload = function() {
            document.querySelector('#progress').value = 100;
            var password = document.querySelector('#password').value;
            var bits = 256;
            var ciphertext = reader.result;
            var plaintext = AesCtr.decrypt(ciphertext, password, bits);
            var blob = new Blob([plaintext], {type: 'application/octet-stream' });
            saveAs(blob, file.name.replace(/\.enc$/,''));
            document.querySelector('#progress').value = 0;
            const t2 = performance.now();
            const t = ((t2-t1)/1000).toFixed(3)+'s';
            document.querySelector('#decrypt-file-time').textContent = t;
            }           

        }
       
    });
</script>