How to determine if PDF is encrypted javascript client side

user_2919101 0
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Need to determine if if pdf uploaded by user is password protected without using external libs. So far got this POC.

Any one know cases when this might not work?

<input type='file' onchange='openFile(event)'><br>
<script>
    var openFile = function (event) {

        var input = event.target;

        var reader = new FileReader();
        reader.onload = function (event) {
            console.clear();
            var contents = event.target.result;
            if (contents.indexOf('/Encrypt') !== -1) {
                console.log("Is encrypted");
            } else {
                console.log("Not encrypted");
            }
            console.log("File contents: " + contents);
        };

        reader.onerror = function (event) {
            console.error("File could not be read! Code "  +event.target.error.code);
        };

        reader.readAsText(input.files[0]);

    };
</script>
passwords encryption pdf javascript
1 Answers

You can use the below code to find whether the PDF is encrypted or not

const reader = new FileReader();
reader.readAsArrayBuffer(file);
reader.onload = function () {

var files = new Blob([reader.result], {type: 'application/pdf'});
files.text().then(x=> {
    console.log("isEncrypted", x.includes("Encrypt"))
    console.log("isEncrypted", x.substring(x.lastIndexOf("<<"), x.lastIndexOf(">>")).includes("/Encrypt"));
    console.log(file.name);
});
user_137409880
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