About Digital Signatures

LibreOffice मा, तपाईँ डिजिटल रुपमा तपाईँको कागजातहरू र म्याक्रोहरूमा हस्ताक्षर गर्न सक्नुहुन्छ ।

Certificates

डिजिटल रुपमा कागजात हस्ताक्षर गर्न, तपाईँलाई व्यक्तिगत कुञ्जी, प्रमाणपत्र आवश्यक पर्दछ । व्यक्तिगत कुञ्जी तपाईँको कम्प्युटरमा व्यक्तिगत कुञ्जीको संयोजनको रुपमा भण्डारण भएको छ, जुन गोप्य रुपमा राखिनुपर्छ, र सार्वजनिक कुञ्जी, जुन तपाईँले हस्ताक्षर गर्दा कागजातहरूमा थप्नु भएको छ ।

कागजात बचत गर्नुहोस् र हस्ताक्षर गर्नुहोस्

जब तपाईँले कागजातमा डिजिटल हस्ताक्षर लागू गर्नुहुन्छ, एक प्रकारको चेकसम र तपाईँको व्यक्तिगत कुञ्जी कागजातको सामग्रीबाट गणना हुन्छ । चेकसम र तपाईँको सार्वजनिक कुञ्जी एकैसाथ कागजातमा भण्डरण हुन्छन् ।

हस्ताक्षर गरिएको कागजात खोल्नुहोस्

जब कसैले LibreOffice को हालको संस्करण सँगै कुनै कम्प्युटरमा पछि कागजात खोल्दछ भने, कार्यक्रमले फेरि चेकसम गणना गर्दछ र भण्डारण गरिएको चेकसम सँग तुलना गर्दछ । यदि दुवै उस्तै भए भने, कार्यक्रमले तपाईँलाई मौलिक, परिवर्तन नभएको काजजात हेर्नुभयो भनेर सङ्केत गर्दछ । थपमा, कार्यक्रमले तपाईँलाई प्रमाणपत्रबाट सार्वजनिक कुञ्जी सूचना देखाउन सक्छ ।

तपाईँ प्रमाणपत्र अधिकारको वेबसाइटमा प्रकाशन भएको सार्वजनिक कुञ्जी सँगै सार्वजनिक कुञ्जी तुलना गर्न सक्नुहुन्छ ।

जब कसैले कागजातमा केही परिवर्तनहरू गर्दछ, यो परिवर्तनले डिजिटल हस्ताक्षर विच्छेदन गर्दछ । परिवर्तन पछि, त्यहाँ तपाईँले हेर्नु भएको मौलिक कागजातमा साइन हुने छैन ।

The result of the signature validation is displayed in the status bar and within the Digital Signature dialog. Several documents and macro signatures can exist inside an ODF document. If there is a problem with one signature, then the validation result of that one signature is assumed for all signatures. That is, if there are ten valid signatures and one invalid signature, then the status bar and the status field in the dialog will flag the signature as invalid.

You can see any of the following icons and messages when you open a signed document.

Icon in Status bar

Signature status

Icon

The signature is valid.

Icon

The signature is OK, but the certificates could not be validated.

The signature and the certificate are OK, but not all parts of the document are signed. (For documents that were signed with old versions of the software, see note below.)

Icon

The signature is invalid.


Signatures and software versions

The signing of contents got changed with OpenOffice.org 3.2 and StarOffice 9.2. Now all contents of the files, except the signature file itself (META-INF/documentsignatures.xml) are signed.

When you sign a document with OpenOffice.org 3.2 or StarOffice 9.2 or a later version, and you open that document in an older version of the software, the signature will be displayed as "invalid". Signatures created with older versions of the software will be marked with "only parts of the document are signed" when loaded in the newer software.

When you sign an OOXML document, then the signature will be always marked with "only parts of the document are signed". Metadata of OOXML files are never signed, to be compatible with Microsoft Office.

When you sign a PDF document, then this marking is not used. Signing only parts of the document is simply an invalid signature.

Signing other document formats is not supported at the moment.

द्रष्टव्य प्रतिमा

When you load an ODF document, you might see an icon in the status bar and the status field in the dialog that indicates that the document is only partially signed. This status will appear when the signature and certificate are valid, but they were created with a version of OpenOffice.org before 3.2 or StarOffice before 9.2. In versions of OpenOffice.org before 3.0 or StarOffice before 9.0, the document signature was applied to the main contents, pictures and embedded objects only and some contents, like macros, were not signed. In OpenOffice.org 3.0 and StarOffice 9.0 the document signature was applied to most content, including macros. However, the mimetype and the content of the META-INF folder were not signed. And in OpenOffice.org 3.2, StarOffice 9.2, and all versions of LibreOffice all contents, except the signature file itself (META-INF/documentsignatures.xml), are signed.


Security Warnings

When you receive a signed document, and the software reports that the signature is valid, this does not mean that you can be absolutely sure that the document is the same that the sender has sent. Signing documents with software certificates is not a perfectly secure method. Numerous ways are possible to circumvent the security features.

Example: Think about someone who wants to camouflage his identity to be a sender from your bank. He can easily get a certificate using a false name, then send you any signed e-mail pretending he is working for your bank. You will get that e-mail, and the e-mail or the document within has the "valid signed" icon.

Do not trust the icon. Inspect and verify the certificates.

चेतावनी प्रतिमा

The validation of a signature is not a legally binding guarantee of any kind.


On Windows operating systems, the Windows features of validating a signature are used. On Solaris and Linux systems, files that are supplied by Thunderbird, Mozilla or Firefox are used. You must ensure that the files that are in use within your system are really the original files that were supplied by the original developers. For malevolent intruders, there are numerous ways to replace original files with other files that they supply.

चेतावनी प्रतिमा

The messages about validation of a signature that you see in LibreOffice are the messages that the validation files return. The LibreOffice software has no way to ensure that the messages reflect the true status of any certificate. The LibreOffice software only displays the messages that other files that are not under control of LibreOffice report. There is no legal responsibility of LibreOffice that the displayed messages reflect the true status of a digital signature.