Email Security Intelligence - Help Strengthen Your Cybersecurity Efforts with Electronic & Digital Signatures

Electronic signatures have become an increasingly standard cybersecurity tool as businesses have moved online. Used appropriately, they can improve business efficiency while protecting the authenticity and integrity of your documents and emails, which is especially helpful in the face of today’s ever-evolving email security risks.

In this article, we will explain electronic signatures, how advanced digital signature technology can enhance emailing safety, and how this can support secure email communication.  

Signing Documents in a Digital Age

Whether for business proposals, contracts, project proposals, mortgage applications,digital electronic signatures or expense claims, it is crucial to approve documents and ensure their authenticity and validity. 

For centuries, ink signatures and other presentational devices maintained message security, the wax seal on old royal proclamations a clear example. However, with the societal transfer to digital documentation, messages are now being shared and agreed upon online more often, from PDFs and emails to even greater forms.

This rapid rise of digital working has endowed great benefits, including flexible, remote working patterns, greater efficiency facilitation with faster turnarounds possible, and minimal carbon footprint given there is less printing and posting of often weighty hard copies. 

This switch, however, raises certain email security issues and concerns: How can businesses verify that all email messages and digital documents are authentic upon being received? Can businesses ensure their integrity is not being tampered with? When essential documents are approved online, are they legally secure?

Questions such as these have always raised challenges. There have been stories of documents being faked, tampered with, or repudiated by an involved party throughout history. But there is little doubt that the complicated cybersecurity landscape of our online world is posing new email threats and risks every day. 

A Palette of Solutions

Fortunately, various new email security technologies offer a variety of solutions that surpass traditional pen and ink signatures. Electronic signatures play a core role in emailing safety, allowing businesses to reap the benefits of working online while substantially mitigating email security risks.

Businesses should consider various questions when making a decision regarding the best approach to electronic signatures, including: What are the different types of electronic signatures? And How does utilizing digital signature technology add an extra layer of email security?

The Legal Landscape

Organizations must know the legal landscape and differences between electronic and digital signatures. Legislation varies between jurisdictions, so businesses may make diflegal landscapeferent decisions about electronic signatures depending on where they are operating. 

In the US, the Uniform Electronic Transactions Act (UETA) is the primary legislation that gives electronic signatures the same legal status as handwritten ones. Meanwhile, the Electronic Identification and Trust Services (eIDAS) regulation operates in Europe. eIDAS is more stringent, as a higher email security threshold must be met to ensure the legal validity of electronic signatures, meaning more robust digital signature email security technologies must be utilized.

Regulations also apply differently depending on the nature of the document. For example, a “Will and Testament” stipulation differs from other business contracts. Thus, organizations must understand the legal requirements of whatever documents they utilize and where they operate.  

What Is an Electronic Signature?

The term “electronic signature” is generic and covers many possible approaches. 

At its most basic level, an electronic signature (or eSignature) replicates in digital form what a handwritten signature does with ink on paper. Electronic signatures could be typing your name on a document, inserting an image of your pen and ink signature (e.g. insert signature in Word document), or ticking an “I consent” box to indicate your approval. 

For many situations, that will be considered enough. If two parties are familiar with each other or work in the same organization and network, they can more easily trust one another. A line manager approving a team member’s time-off request would only need this simpler form of electronic signature.

However, electronic signatures utilize digital signature technologies to offer additional, sophisticated layers of email security that make documents safer and more trustworthy upon being sent.

What Are the Three Main Types of Electronic Signatures?

There are three main types of electronic signatures: simple, advanced, and qualified. Each involves different technologies, protocols, and security measures, thus offering different levels of email protection, investment requirements, and legal ramifications. Let us consider each type in turn, starting from the very simplest.

Simple Electronic Signatures (SES) 

Europe defines Simple Electronic Signatures (SES) as "data in electronic form which is attached to or logically associated with other data in electronic form and used by the signatory to sign." Essentially, SES is a basic type of electronic safety and, as such, can take a wide variety of forms, including:

  • Typing your name on a document.
  • Scanning and inserting your signature.
  • Clicking on an “I accept” button.
  • Attached is an audio file responding to a request.  

An SES entails an acknowledgment and acceptance of the document concerned. When formatted carefully, SESs can look competent and professional, adding informal weight to business communication. However, this is all that SES can do, which may or may not be an issue. Consider the following:

  • e signature typesAn SES does not include user ID authentication and verification, so you cannot be sure who signed the document, as the signature does not prove to be from the correct signer.
  • An SES alone does nothing to protect the integrity of a message or document, so it may get altered at some point during the signing process (whether accidentally or deliberately). Such an issue is usually overlooked; if discovered, it can be challenging to figure out when and how it happened.

Where trust can be assumed, and the risk of tampering is very low, using an SES alone will often be deemed sufficient. SESs are quick (almost instant) and involve minimal costs, effort, and additional infrastructure. Moreover, such a signature can be considered legally binding in certain circumstances. 

Usually, the authentication and integrity limitations described above leave an organization vulnerable, as trust between parties is more subtle, leaving companies more susceptible to higher stakes and more stringent legal requirements in email security. In those instances, extra safe cybersecurity platforms are needed, meaning digital signature technology should be utilized.

Advanced Electronic Signatures (AES)  

Following the SES, we can assess Advanced Electronic Signatures (AES). An AES starts with features similar to an SES but has a more sophisticated range of digital signature technology, including cryptographic assistance. Here are some of the benefits of using an AES:

  • It offers an authentication process that verifies the signer's identity, validating that the person who signs the email or document is who they claim to be and helping protect against fake or malicious communications.
  • There are steps to ensure the document's integrity or communication to prevent tampering. AES can pick up even the tiniest of changes, like a deleted comma or other punctuation alteration.
  • These greater email security features offer the benefit of non-repudiation. With a clear audit trail, the signer cannot deny signing the document or message in that form.

The above means that an AES offers far more cybersecurity tools than an SES. However, there is sometimes a need for an even higher level of email security.

Qualified Electronic Signatures (QES)

A Qualified Electronic Signature (QES) utilizes digital signature technology to verify the sender and protect the integrity of a message or document once signed, ensuring non-repudiation. In these aspects, AES and QES are similar. 

However, a QES provides even greater confidence in those protections, automatically providing more legal weight to a signature. In Europe, under the eIDAS regulations, a QES is the only electronic signature type currently automatically deemed to have legal equivalence to a handwritten signature. Therefore, QES provides the highest level of email security for electronic signatures.

What Is a Digital Signature?

There is some confusion about the terms “electronic signature” adigital signaturend “digital signature,” which are sometimes used interchangeably and in different ways depending on where you are. Legal situations in various territories can lead to these inconsistencies and other times, misunderstanding these two phrases can cause improper communications.

SES, AES, and QES are all considered electronic signatures. Digital signatures are a narrow subset; only AES and QES qualify under such descriptions.

A digital signature is generally more sophisticated than a simple electronic signature, as layers of email security are devoted to cryptographic cybersecurity tools that ensure signatures are safe. As a result, digital signatures tend to be better suited for identification and preventing further email threats. 

What Is the Difference between a Digital Signature and an Electronic Signature?

There are, then, some notable differences between these two types of verification email security technologies, which are summarized below:


An SES is a straightforward expression of authorship, acknowledgment, or agreement regarding a document. A digital signature, on top of this, verifies and protects the integrity of the document. SESs require trust between the sender and receiver, whereas a digital signature does not.

Common use cases

SES, AES, and QES offer an email security hierarchy of approaches depending on the context. When risks are small, SES can be useful for low-stake communications between friends, colleagues, or clients.

However, utilizing an AES provides a more helpful way to secure email when trading formal agreements, such as employment, rental, and sales contracts. A QES is better for large-value financial transactions or other crucial legal documents (like NDA templates). 

Ease of creation and investment required

Applying a Simple Electronic Signature to a document can be quick, easy, and cheap. As we have seen, it can be as simple as typing a name, inserting an image, or ticking a box. It requires no particular additional equipment, infrastructure, or investment.

Digital signatures, on the other hand, are a more complex affair. The sophisticated cryptographic technology relies on costly requirements for installation. Businesses wishing to issue digital signatures must purchase digital certificates that can be expensive to secure and retain, especially as they must be renewed relatively frequently. 

Given the greater complexity involved, organizations that use AES or QES usually invest in third-party document signature cybersecurity tools to manage the handling process. There are many of these to choose from, each offering slightly different processes, features, and prices (see this DocuSign API pricing blog, for example). Therefore, choosing one for a business can be time-consuming and require frequent review, so companies must ensure their email platform can support such a system.

However, with strong tools and processes in place, much of the cryptographic complexity involved in digital signatures can be concealed from users themselves. For example, users do not have to be fully aware of how “public” and “private” keys, digital certificates, and hash functions keep everything in order behind the scenes.

Third-party document handling tools can smooth out the process for all electronic signatures. Much of the workflow involved in digital signing can be automated, helping to reduce the scope of human error. Nevertheless, digital signatures’ greater email protection also requires effort and money to ensure those systems are established and properly maintained.   

Level of protection and security

A digital signature authenticates the sender or signer’s identity and the message or document’s integrity, ruling out repudiation further down the line. 

An Advanced Electronic Signature (and even more so a QES) offers comprehensive email protection. This can ensure that all documents are sent in high confidence, as all signatures are sealed. If the document is altered after signing, it will be flagged.

On the other hand, a Simple Electronic Signature is often just a name or additional insertion added to a document. As a result, anyone could insert the signature into the document, so there is less certainty concerning whether or not a document has been altered once signed.

Legal status

The legal status of the various electronic and digital signature types varies depending on the territory and the use case. Some documents (like Wills) tend to have more stringent legal requirements concerning signatures. More advanced digital signatures carry far more weight than straightforward electronic signatures, making them a requirement of legal documents.

What Is the Importance of Electronic Signatures in Cybersecurity?

Even technically simple electronic signatures offer security advantages over traddigital esig cybersecurityitional pen and ink (or ‘wet’) signatures. While just typing a name on a document or clicking a box may not seem very secure, various approaches can be used to incorporate a more robust SES setup to guarantee email security.

Europe’s eIDAS regulations are deliberately quite open about the exact nature of SES technology, leaving room for technical innovation. The SES category is diverse and vast, opening the door to more secure approaches. Consider the following: 

  • While still vulnerable, an SES signing process can authenticate using personal details (phone numbers or email addresses). 
  • Using PIN codes or passwords as part of the signing process makes the SES far more secure. For example, it might include sending a unique, time-limited passcode to the signer’s mobile phone.
  • Biometric identification is becoming more common and could become part of a signing process.
  • While cryptographic keys are usually associated with digital signature technology, these can be used in different ways to enhance email security. 
  • Robust general cybersecurity tools can make for safer electronic signing processes.     

In other words, even though a Simple Electronic Signature is not fully digital, it still needs to be secured so they are not vulnerable. Ultimately, there are many ways of setting up electronic signatures, with many having more secure email benefits than others.

What Is the Importance of Digital Signatures in Cybersecurity?

While there are other ways of enhancing cybersecurity trademarks, digital signatures currently provide the most robust, consistent, and established framework. Businesses benefit from approving crucial documents and signing off emails using these advanced methods, as recipients can be confident that a communication is genuine.

What follows describes a typical process for an Advanced Electronic Signature (AES), though each document handling platform works slightly differently. A Qualified Electronic Signature (QES) is broadly similar but has a few additional features.

Digital certificates

Before you can digitally sign something, you need a digital certificate.

Digital signatures are facilitated by the Public Key Infrastructure (PKI), a set of protocols, procedures, software, and hardware. PKI governs how a network of organizations called Certificate Authorities (CA), a type of Trusted Service Provider (TSP), can issue digital certificates that enable advanced signatures. 

With this certificate, a business (or individual) can add a digital signature to the documents and messages they send. Acquiring that digital certificate acts as validation that the company (or individual) is who they say they are because it is the responsibility of the trusted, third-party CA to check before issuing the certificate. 

In other words, having the digital certificate authenticates the sender so recipients can trust the data’s provenance. It also makes two critical cryptographic cybersecurity tools available for the signature: a “private key” and a “public key.” The former allows the sender to add their digital signature to subsequent communication, enabling recipients to verify that signature.

Generating a Digital Signature

qesWith a digital certificate and appropriate procedural tools (e.g., a robust, secure email platform or document signing program), the business can add its digital signature in the following process:

  1. Once the message or document is ready to send, the document signing program or email platform generates a unique hash code. This represents the message in a fixed-length, coded form of numbers and letters. A completely different hashcode is generated if even one aspect of the original message is changed (like a comma deleted).
  2. This hash code is then encrypted using the sender’s “private key” (provided by the digital certificate) that applies a mathematical algorithm unique to the sender to the hash code. The encrypted hash code can only be decrypted with the sender’s public key.
  3. The resulting encrypted hash code becomes the central element of the sender’s digital signature, which includes a hashing algorithm and the date stamp for when the sender “signed” the document.    
  4. The message or document and its digital signature can then be sent to the recipient. However, the Certificate Authority may sometimes require additional information before that can happen.

Note that the private key encrypts the hash code - the digested version of the message - rather than the message itself. This increases the speed and efficiency of the process. The hash code is far shorter: any document gets condensed into a fixed-length digest. This code is usually much quicker to encrypt than the entire document itself.  

Authenticating the Digital Signature

Once the message and digital signature are sent, a similar process is followed but in reverse order:

  1. The receiver’s computer applies the hashing algorithm to the document or message to generate a hash code. Because the receiver uses the same hashing algorithm as the sender, the resulting codes should match if the document or message is unchanged.
  2. Simultaneously, the receiver’s computer can obtain the sender’s “public key” from the relevant Certificate Authority, which applies this public key to the encrypted hash code from the sender or decrypts the hash code sent with the message. 
  3. By comparing the two versions of the hash code, the receiver’s computer can then confirm or deny the authenticity and integrity of the message or document. If the hash code generated in step 1 matches the decrypted hash code from step 2, the message was not altered in any way after signing. In that case, the receiver can sign and return the document when required. However, they may have to complete further email security steps before adding their electronic signature.

On the other hand, if the two hash codes do not match, something has gone wrong, but this process cannot ascertain what happened. There are two possibilities: the message has been altered or tampered with, causing differing hash codes, or the public and private keys do not align, suggesting an issue with sender authentication. In either case, the digital signature would be flagged as invalid.

Simple for the user

Setting up a digital signature and certificate is a huge process. A business must acquire a digital certificate by applying to a Certificate Authority, which can be expensive, but having the download will make business operations easier over time.

From there, most document management and email applications can deal with the technical details, drawing on the certificate to automate most of the work. A user only has to click “Digitally Sign” in order for the signature to be applied, which is done automatically.

While the sender’s digital signature is often required, the digitally signed response is not. When a reply requires a signature, services will often automate the process. If there are complications, it is usually because a recipient does not have a digital certificate or use the same services.

How are Qualified Electronic Signatures different?

Qualified Electronic Signatures (QES) are the same as Advanced Electronic Signatures. Still, QESs include a few additional characteristics that can enhance the recipient’s confidence that the received data has authenticity and integrity. 

A QES requires a sender to have a QES that can only be issued by a qualified, trusted service provider. This status is awarded to organizations at a governmental level, with the state providing the rights. 

Once a business has been deemed qualified, the certificate provider must ensure the applicant is who they claim to be and ensure authenticity remains. This can be done through face-to-face contact with the other person, whether in person or online, to ensure that the person asking for a QES is validated.

A QES also involves using a Qualified Electronic Signature Creation Device (QSCD) that involves certified software or hardware, whether a cloud email security module or USB token. This ensures additional email security in various ways, such as ensuring that cryptographic keys are created correctly, stored securely, and used only by the right people.    

The above makes QES more complex and expensive, so they are typically used for sharing the most high-stakes messages and documents.          

What Are the Potential Security Drawbacks of Digital Signatures?

Electronic signatures - especially those supported by digital signature technology - can be a secure way to share documents and messages. However, there are still risks to keep in mind. 

Can it be easy to forge simple electronic signatures?

Firstly, the more basic the electronic signature, the more vulnerable it is from a cybersecurity perspective. As we have seen, Simple Electronic Signatures (SES) are open to misuses like forging an eSignature. Additional email security measures such as PINs and passwords can improve things, but there are still many opportunities for fraud and misuse.

Digital signatures are not immune to danger.

Both simpler and advanced signatures are at risk, as even cryptographic private keys can be stolen since hackers like to target them where possible. 

A stolen private key can cause many problems. Cybercriminals can use a private key to sign fake messages and documents, launch phishing email attacks by disguising themselves as a legitimate source, and more. The vulnerability of cryptographic keys is one reason why a QES (which uses QSCD to protect the cryptographic keys) offers a higher level of email protection.

And other risks have been identified in the digital signature process – vulnerabilities that hackers can exploit. A digital signature does not encrypt (or hide) the message itself; business cybersecurity platforms need to consider such email security risks so they can be addressed as soon as possible.

Phishing scams

The perception of security offered by digital signatures can make them a tempting target for cybercriminals. For example, scammers have tried phishing campaigns that mimic legitimate businesses sending out documents to be signed. 

Targets are sent eSignature envelopes (as an email) inviting them to reve2eeiew and sign a document. If the target clicks on the link, they are taken to a fake site requesting them to enter personal credentials that can be exploited or a malicious document that downloads malware onto their computer. Cybercriminals are inventive and will try to bypass a business’s email security measures to exploit weaknesses. 

Businesses need to consider how their customers and employees may be targeted in this way via phishing email attacks. Companies should ensure that their emails are consistently branded and presented so that malicious emails can be spotted more easily by employees who are trained and updated regarding the dangers they might encounter. Such workers are also well-versed in the best practices for email security.

Not a silver bullet

Digital signatures should be part of a coherent and robust overall cybersecurity posture, as using digital signatures does not lessen the need for many other aspects of cybersecurity. 

A business is only as secure as its weakest link. Therefore, companies must use the best multifaceted defenses. In a bit, we will go over end-to-end encryptions like TLS and how, alongside digital signatures, they can add another layer of email protection by encrypting the message itself. Combining various approaches, a coherent strategy will likely leave fewer vulnerabilities in your online operations.      

Evolving dangers

And finally, the cybersecurity landscape is constantly evolving. Cybercriminals always seek new techniques to exploit cybersecurity vulnerabilities and email security risks. In this shifting context, using digital tools, including electronic signatures, must be regularly risk assessed. 

Frequently Asked Questions about Digital Signatures and Email Encryption

Much more is involved to fully understand how digital signatures and email protection encryption can support cybersecurity. Here are a few frequently asked questions:

Are Outlook digital signatures sufficient for secure emails?

An Outlook digital signature offers a reasonable level of email security when sending data. However, if data privacy is also a concern, Outlook digital signatures can be combined with email encryption. 

What is S/MIME?

S/MIME Encryption (Secure/Multipurpose Internet Mail Extensions) is an email security protocol combining a digital signature's benefits with email encryption. The message encryption element means third parties cannot spy on your communications. The digital signature element demonstrates the authenticity and integrity of your emails while establishing non-repudiation. 

What are the benefits of using a digital signature certificate?

A digital signature certificate authenticates a business or individual. A validated certificate is required to allow them to add their digital signature to documents and messages. A certificate is also necessary to enable them to encrypt data.

Can I use the same certificate on my laptop and mobile device?

Yes, digital signature certificates can be ported to your mobile devices.

Keep Learning About Strengthening Your Cybersecurity Strategy

There is little doubt that digital signatures are a great way to handle documents and emails securely. Moreover, they help a business demonstrate integrity and authenticity to its stakeholders: clients, customers, and suppliers. When combined with encryption techniques, the privacy of those communications can be protected.   

However, technology is moving ever so fast. That means new opportunities and dangers are constantly emerging. It is crucial to stay up-to-date with the latest cybersecurity tools, ensuring that your security posture is evolving to meet the challenges of each new day. There is no room for complacency.

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