What is a Signature?

Within the digital realm, a signature can be defined as a multi-faceted tool, a distinctive service, or a form of data that plays a crucial role in various contexts. As a form of data, there are three primary types of digital signatures: Simple (SES), Advanced (AES), and Qualified (QES). Simple electronic signatures (SES), the most commonly used type, facilitate everyday transactions and generally act as a digital equivalent to handwritten signatures. Advanced electronic signatures (AES) introduce additional user authentication steps and are used for high-value transactions, while Qualified electronic signatures (QES) are utilized for highly regulated transactions, requiring face-to-face or equivalent ID verification.

When it comes to software, a signature serves as a means of confirmation, identifying the author of the software and ensuring the software's integrity by guaranteeing it has not been altered post-signing. This is achieved through code signing, which employs cryptographic hashes to maintain the authenticity and integrity of the software. Introduced by Michael Doyle in 1995, code signing has become integral to security in software deployment, updates, and patches, as well as in preventing namespace conflicts in certain programming languages. It is widely adopted across operating systems such as Windows, Mac OS X, and most Linux distributions, which require software authentication upon first run. However, it is important to recognize that while code signing verifies authorship and integrity, it does not safeguard users against bugs or malicious intent by the software author.

As a type of service, a signature service refers to a unique offering that distinguishes a company or brand from its competitors. Signature services are tailored to be distinctive and characteristic of the brand providing them, serving as a hallmark of the company's identity and reinforcing its position in the marketplace.

Signature Plugins for Excel

Signaturely Plugin for Excel

Signaturely is a good signature plugin for Excel, recommended for its enhanced security and convenience over Excel's native options. It also boasts more advanced features, making it a superior choice for users who require robust digital signature functionality within Excel.

Excel's Built-in Digital Signature Line Feature

Excel includes a built-in digital signature line feature that enables users to insert digital signatures directly into their Excel documents. This feature provides a basic level of digital signature capability without requiring additional plugins.

Common Use Cases

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  Creating legally binding business documents directly within Excel
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  Reviewing and signing Excel files attached to PandaDoc documents
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  Ensuring the authenticity of a workbook or macro before distribution
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  Securing business transactions by confirming the signer’s identity through a digital certificate
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  Preventing unauthorized alterations to Excel documents post-signing

Frequently Asked Questions

How do I create a digital signature in Excel?

To create a digital signature in Excel, you need a digital certificate from a certifying authority. Once you have the certificate, you can add a signature line to your workbook and use the Sign dialog box to apply your digital signature, which will make the document read-only to prevent further modifications.

Can I still edit an Excel workbook after it has been digitally signed?

You can view and edit a signed Excel workbook, but once you save any changes, the existing digital signature will be invalidated. To maintain the signature's validity, do not save changes after signing.

Do digital signatures work in all versions of Excel?

Digital signatures are recognized from Excel 2003 and later versions. However, Excel versions earlier than 2002 do not recognize digital signatures, and signatures are not retained in shared workbooks.

Can I see who has signed an Excel document and check its integrity?

Yes, to verify a signed workbook's integrity and see who the signers are, you can check the signature pane or dialog box. Closing and reopening a signed workbook will also show the signature status in the Excel title bar.

Is it possible to add comments or a date when signing an Excel document?

Yes, Excel's signature feature provides an option to allow signers to add comments and the signature line can show the sign date when you are setting up the signature.