Ich habe versucht, einen Pdf-Blob zu verschlüsseln und ihn im localStorage zu speichern. Wenn ich offline bin, kann ich ihn später lesen und entschlüsseln.

Meine App ist in AngularJS geschrieben und die Verschlüsselung erfolgt mitSchmied

Hier ist mein Code zum Herunterladen der PDF-Datei:

$http.get(url, {
                    headers: {
                        "Application-Authorization": appContext.user.token
                    },
                    responseType: "blob"
                }).then(function(response) {

                    backendCipherService.encryptPDF(response.data, appContext.user.password).then(function(data) {
                        $localForage.setItem("document::" + document.documentId + "::pdf", data.json).then(function(success) {
                            console.log("cached pdf", document.documentId);
                            deferred.resolve();
                        }, function(error) {
                            console.log("Error", response.data, document.documentName);
                            deferred.reject(error);
                        });
                    });
                }, function(error) {
                    deferred.reject(error);
                });

und hier ist mein Code für die Ver- und Entschlüsselung (backendCipherService):

this.encryptPDF = function(blob, password) {
            var salt = forge.random.getBytesSync(256);
            var key = forge.pkcs5.pbkdf2(password, salt, 40, 32);
            var iv = forge.random.getBytesSync(32);
            var cipher = forge.cipher.createCipher('AES-CBC', key);

            cipher.start({iv: iv});
            var deferred = $q.defer();

            var uint8Array  = null;
            var arrayBuffer = null;
            var fileReader     = new FileReader();
            fileReader.onload  = function(progressEvent) {
                arrayBuffer = this.result;
                uint8Array  = new Uint8Array(arrayBuffer);
            };
            fileReader.readAsArrayBuffer(blob);
            fileReader.onloadend = function() {
                var inp = uint8Array;
                console.log(inp);
                cipher.update(forge.util.createBuffer(inp));
                cipher.finish();
                var encrypted = cipher.output;
                var data = forge.util.bytesToHex(encrypted);
                var obj = {"salt": forge.util.bytesToHex(salt), "iv": forge.util.bytesToHex(iv), "encrypted": data};
                deferred.resolve({
                    json: angular.toJson(obj)
                });
            };
            return deferred.promise;
        };

        this.decryptPDF = function(json, password) {
            var obj = angular.fromJson(json);
            var key = forge.pkcs5.pbkdf2(password, forge.util.hexToBytes(obj.salt), 40, 32);
            var iv = forge.util.createBuffer();
            var data = forge.util.createBuffer();
            iv.putBytes(forge.util.hexToBytes(obj.iv));
            data.putBytes(forge.util.hexToBytes(obj.encrypted));

            var decipher = forge.cipher.createDecipher('AES-CBC', key);
            decipher.start({iv: iv});
            decipher.update(data);
            decipher.finish();
            return decipher.output.data;
        };

und hier ist der Code zum erneuten Konvertieren des entschlüsselten Werts in einen Blob:

return $localForage.getItem("document::" + documentId + "::pdf").then(function(pdf) {
                var pdfBlob = new Blob([backendCipherService.decryptPDF(pdf, appContext.user.password)], {type: 'application/pdf'});
                return pdfBlob;
            }, function(error) {
                return error;
            });

Dies funktioniert im Allgemeinen, aber das PDF kann nicht aus PDF.js gelesen werden und ich erhalte den Fehler:

Error: Bad FCHECK in flate stream: 120, 194
pdf.worker.js:252     at error (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:252:15)
    at Object.FlateStream (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:31394:7)
    at Object.Parser_makeFilter [as makeFilter] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:30281:18)
    at Object.Parser_filter [as filter] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:30259:25)
    at Object.Parser_makeStream [as makeStream] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:30234:21)
    at Object.Parser_getObj [as getObj] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:30022:28)
    at Object.XRef_fetchUncompressed [as fetchUncompressed] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:4323:28)
    at Object.XRef_fetch [as fetch] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:4280:26)
    at Object.XRef_fetchIfRef [as fetchIfRef] (http://localhost:8080/client/components/pdfjs-dist/build/pdf.worker.js:4261:19)
pdf.worker.js:235 Warning: Unsupported feature "unknown"
pdf.worker.js:235 Warning: Invalid stream: "Error: Bad FCHECK in flate stream: 120, 194"
pdf.js:235 Warning: Unsupported feature "unknown"

Es scheint, dass das PDF irgendwie beschädigt ist.

Irgendwelche Ideen, was ist los? Dank