Method decryptObject

src/parser/document-parser.ts:583–649

(obj: PdfObject, objNum: number, genNum: number)

     * Decrypt an object's strings and stream data.
     */
    const decryptObject = (obj: PdfObject, objNum: number, genNum: number): PdfObject => {
      try {
        if (!securityHandler?.isAuthenticated) {
          return obj;
        }

        if (obj instanceof PdfString) {
          const decrypted = securityHandler.decryptString(obj.bytes, objNum, genNum);

          return new PdfString(decrypted, obj.format);
        }

        if (obj instanceof PdfArray) {
          const decryptedItems: PdfObject[] = [];

          for (const item of obj) {
            decryptedItems.push(decryptObject(item, objNum, genNum));
          }

          return new PdfArray(decryptedItems);
        }

        // Check PdfStream BEFORE PdfDict (PdfStream extends PdfDict)
        if (obj instanceof PdfStream) {
          // Check if this stream should be encrypted
          const streamType = obj.getName("Type")?.value;

          if (!securityHandler.shouldEncryptStream(streamType)) {
            return obj;
          }

          // Decrypt stream data
          const decryptedData = securityHandler.decryptStream(obj.data, objNum, genNum);

          // Create new stream with decrypted data
          // Copy dictionary entries (strings in dict will be decrypted when accessed)
          const newStream = new PdfStream(obj, decryptedData);

          // Decrypt strings in the dictionary entries
          for (const [key, value] of obj) {
            const decryptedValue = decryptObject(value, objNum, genNum);

            if (decryptedValue !== value) {
              newStream.set(key.value, decryptedValue);
            }
          }

          return newStream;
        }

        if (obj instanceof PdfDict) {
          const decryptedDict = new PdfDict();

          for (const [key, value] of obj) {
            decryptedDict.set(key.value, decryptObject(value, objNum, genNum));
          }

          return decryptedDict;