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The Ultimate Guide on Electronic Signatures, Digital Signatures, and Email Signatures

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Digital signatures. Electronic signatures. Email signatures. They all sound like the same thing. After all, they all are used for providing a sign-off online.

However, although they are often used in the same context, they are different. They are used for different purposes, and it is a mistake to think they all do the same thing. So, learning how to electronically sign in an email is different from using an email signature to end an email.

This article looks at these three types of signatures to help you understand their differences and the contexts they are used for.

What is an email signature?

An email signature is a contact block added to an email at its basic level. Essentially, it’s an electronic business card. It gives information to a recipient on how to contact the person who’s emailed them. It’s a simple item that appears in standard corporate email.

Email signatures can be used on personal emails for various purposes. However, in this instance, the email signatures we’re talking about are used on corporate email. This means the emails you and your colleagues send out daily on behalf of your company.

An email signature typically contains the following contact information:

  • Your full name
  • Company name
  • Job title
  • Phone number
  • Company website URL

Looking beyond the contact details and legal disclaimer, email signatures are a great avenue to promote your latest content, broaden your social reach, and maintain brand consistency. They can also be used to showcase and extend the reach of your key marketing communications activities. However, it is crucial to understand that email signatures differ from electronically signing an email.

HTML email signature templates often include:

To learn more about using email signatures effectively, read Professional Email Signature Examples and How to Write Them.

Also, if you want to ensure that you can easily manage all email signatures for your users and save hours of time, check out how Exclaimer can help.

What is an electronic signature?

An electronic signature, often referred to as an e-signature, is used to electronically sign an email document online. You often use one to show that you agree with the contents/terms and conditions of a document, form, or request. An electronic signature is often used to sign a document sent by email.

Sign documents online with an electronic signature

Simply put, an electronic signature is the digital equivalent of signing a paper version of a document. The intent of the signature is the same, with the only difference being that it is captured electronically rather than handwritten. It represents a clear agreement entered willingly on behalf of two or more parties and is often legally binding.

Examples of documents that can be signed using an e-signature include:

  • Contracts
  • Invoices
  • Agreements
  • Receipts

An electronic signature doesn’t necessarily have to look the same as the handwritten signature of the person who signs it. It can be an image of a signature that is pasted into a Word or PDF document. It can be a signature that is hand drawn using a mobile device. It can even simply be a name typed into a signature box.

Many businesses find that the safest way to electronically sign a document sent by email is to use a solution like Adobe Sign or DocuSign. And as there are legal requirements around electronic signatures, it’s essential to be aware of key legislation that affects their use.

Electronic signature laws in the U.S.

In the United States, electronic commerce transactions are governed by the Uniform Electronic Transaction Act (UETA) and the Electronic Signatures in Global and National Commerce Act (ESIGN). These laws also highlight that electronic signatures should be recognized as legally acceptable when there is a statutory requirement for a signature.

Both ESIGN and UETA describe five main elements that make an e-signature binding:

  • Validity: Signatures created electronically carry the same legal weight as handwritten versions, so they cannot be invalidated.
  • Consent: The person signing must consent to use an electronic signature.
  • Intent: An e-signature requires that the person signing intends to sign the document.
  • Recording: An e-signature must be accompanied by proof that this is an electronic signature.
  • Data integrity: Documents that have been e-signed must be kept secure from being tampered with.

Electronic signature laws in the European Union and the UK

The European Union has adopted a similar policy known as the electronic Identification, Authentication and Trust Services (eIDAS) regulation. This establishes a legal framework for the provision and effect of electronic signatures. It mandates that these types of signatures can be used with handwritten ones no matter which EU Member State the transaction takes place in.

eiDAS defines three types of e-signature:

  • Simple or basic electronic signature (SES)
  • Advanced electronic signatures (AdES)
  • Qualified electronic signatures (QES)

Simple electronic signatures are the most widely used. There are a few different ways that you can agree to something electronically using an SES. This can be as simple as clicking an “I Agree” button or scanning a copy of your handwritten signature.

An SES provides the lowest levels of legal assurance and is challenging to verify. Using an SES is not considered secure enough in highly-regulated industries such as healthcare, finance, and legal. This is because the receiver cannot verify the sender’s identity accurately.

An SES is also highly vulnerable to tampering and Man-in-the-Middle (MITM) attacks. If a document gets hijacked during transit with no security, there is a severe risk of data breaches occurring to both parties.

When electronic signatures are needed for legal matters or large financial transactions, advanced electronic signatures are required. These have to meet much higher levels of identity verification and security set out by eiDAS. An AdES must be uniquely and clearly linked to its signer and allow for formal identification. The final document must also be completely tamper-proof and created under the signer’s sole control, e.g., via their personal computer.

The highest type of e-signature is known as a qualified electronic signature. This carries the same legal weight as handwritten signatures. Signers are required to use a certificate-based digital ID issued by a qualified EU Trust Service Provider (TSP).

The UK uses a similar approach to the European Union with the UK Electronic Communications Act 2000.

What is a digital signature?

A digital signature differs from e-signatures even though the two terms are used mutually. Instead, a digital signature uses encryption technology to sign and validate the authenticity of a document. It adds additional security levels rather than being a signature in its own right.

In the UK and EU, digital signatures are essential to advanced and qualified electronic signatures.

Using an identity-based certificate (often a Public Key Infrastructure (PKI) based digital certificate), digital signatures are permanently embedded within a document, preventing any further changes from being carried out.

Adding a digital signature improves document security

A digital signature uses mathematical algorithms to prevent forgery and tampering during the sending and receiving process. They have been likened to a fingerprint, as in they are unique.

A digital signature makes a document much more secure and easier to audit. This is important when it comes to verifying the identity of the original sender.

The cryptographic operation of digital signatures has three primary purposes:

  • Authentication: This proves that the document was signed by the person who claimed to sign it.
  • Non-repudiation: This ensures the sender cannot deny having sent the message at some point in the future. This can often be important if an audit trail is required.
  • Integrity: This guarantees that the document was not modified in transit. Once a document is signed, any attempts to change it will make the signature invalid.

How does a digital signature work?

Sensitive information is protected through the use of public and private keys:

  • Private key: known only to the person it belongs to
  • Public key: shared with anyone who needs to access the document

When recipients receive the document, they decrypt the digital signature using the signer’s public key. They then need to hash the document with the same hash formula as the one that the sender used to check its integrity.

These hashes cannot be easily undone. If the formulas are the same, the document has not been tampered with since it was originally signed.

Using digital signature certificates

A digital signature certificate (DSC) is a fundamental digital signature component. It provides the public key used to validate the private key associated with the signature.

There are three classes of certificates:

  • Class 1: Provides basic security and is not legally binding for business documents. Signatures are validated based only on email ID and username.
  • Class 2: Authenticates a signer’s identity against a pre-verified database and is used in moderate-risk environments. Signatures are often used for electronic filing (e-filing) of tax documents.
  • Class 3: Requires a person to present in front of a certifying authority to prove their identity before signing. These are usually used for e-ticketing, e-auctions, e-tendering, court filings, or where a data breach would result in severe consequences.

The easiest way to manage digital signatures is with dedicated solutions like DocuSign, HelloSign, or RPost.


It’s important to note that email signatures, electronic signatures, and digital signatures are three very different things.

Email signatures are a digital way of presenting contact details at the end of an email message. They will also include an email disclaimer for compliance purposes in the business world. Then, other HTML elements can be incorporated, such as banners, social media icons, etc. However, without specialist software, managing email signatures can be very time-consuming.

Compared to email signatures, electronic signatures (e-signatures) are defined legislatively as a digital version of a handwritten signature. They are used to verify a document and capture a signature electronically.

Finally, a digital signature is a cryptographic process or mathematical algorithm that authenticates a data sequence. It is not a signature in its own right. Instead, it protects a document from being tampered with, safely securing the data within. Think of it as a “padlock” on a document that can only be opened by the appropriate people.

It’s easy to get confused when discussing these three signature types, so hopefully this guide has given you insight into what each one does and how they differ.

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