Posted by Pehon Nov 12, 2021 2:39:32 PM

A digital signature is a modern alternative to signing a document using paper and pen. Think of it as an electronic fingerprint that solves the problem of impersonation and tampering in digital communication. A digital signature is commonly confused with an electronic signature (e-signature), but both are different.

Electronic documents, transactions, and digital messages can benefit from digital signatures as proof of origin, identity, and status. Any party can also use them to affirm informed permission by signers.

Digital signatures are legally binding in many countries, including Singapore and the United States, like traditional handwritten document signatures are.

Digital signatures use a standard, approved format called Public Key Infrastructure (PKI) to ensure the highest levels of security and universal acceptance. It's important to note that digital signatures are not the same as electronic signatures.

How does digital signature work?


Digital signatures are used to identify people and protect the information in digital messages and documents by creating a virtual fingerprint that is unique to them. The content becomes part of the digital signature, and digital signatures are much more secure than other types of electronic signatures.

Digital signatures work by proving that a document or digital message has not been altered after the signer signed the document, either intentionally or unintentionally. 

This immutability is achieved using digital signatures, which generate a unique hash of the message or document and encrypt it using the sender's private key. The hash generated is specific to the statement or document, and changing any component would result in it being completely different.

The document is then digitally signed and transmitted to the intended recipient. The recipient then creates their hash of the digital paper and uses the sender's public key to decrypt the sender's hash (included in the original message). 

The recipient checks their hash to the sender's decrypted hash; if they match, it means the message or digital document hasn't been tampered with, and the sender is verified.

If the recipient can't open the document using the signer's public key, there's a problem with the signature or the document. This is the process by which digital signatures are verified.

All parties must trust that the person who creates the signature has kept the private key secret for digital signature technology to work. If someone else has access to the private key, they could forge digital signatures in the owner's name.

What are the benefits of digital signatures?


Digital signatures provide various advantages over other types of electronic signatures, including:

An extra layer of security

A digital signature is more secure than an electronic signature. A digital signature's unique identifying "fingerprint" data is embedded permanently within a document. A document that has been tampered with is easy to spot since a different "fingerprint" would be generated from the slightest change. 

A digital signature provides the highest and most verifiable standard for identifying an individual by an electronic signature using encryption verification technology known as Public Key Infrastructure (PKI). The coded message of a digital signature uniquely identifies the signer and links them to a specific recorded document.

Global acceptance

More countries accept digital signatures for legally binding documents as security procedures supplied by various providers meet international standards.

Today, most governments recognise digital signatures. Digital signatures are formally permitted in Singapore and the U.S. Some European, Asian, and South American countries have different electronic and digital signatures criteria.

Faster transactions 

Retaining customer satisfaction isn't always easy in the modern market, but digital signatures make it faster to complete transactions. 

This establishes you as a helpful partner and demonstrates that you consider your partners' and clients' busy schedules. By empowering your clients in this way, you may increase client retention while also establishing new client ties right away.

Fewer errors than traditional systems

There is no room for error when it comes to contracts. Unfortunately, mistakes and signatures in the wrong fields are common in paper-based systems, making contract management a nuisance. Contract automation or form automation with digital signatures, on the other hand, can substantially reduce the frequency of errors by demanding a check at each step of the validation process for enhanced control and convenience.

Easier to deal with disputes

When using a paper-based system, disputes over transactions might be messy. With a digital signature, though, you can easily track its progress. You can trace a transaction from start to finish, including who owned it at each stage, when it happened, and what it was about—even if the transaction took place months ago.

How is a digital signature created?


Signing software, such as an email application, produces a digital signature by generating a one-way hash of the electronic data to be signed.

An algorithm generates a fixed-length string of letters and integers called a hash. This hash is encrypted using the private key of the digital signature originator. The digital signature is comprised of the encrypted hash, as well as other information such as the hashing algorithm.

Because a hash function can turn any input into a fixed-length result, which is usually significantly shorter, encrypting the hash rather than the entire message or document is preferable, hashing is much faster than signing; therefore, this saves time.

A hash's value is unique to the data it hashes. Any modification in the data, even a single character change, will result in a new value. This property allows others to decrypt the hash using the signer's public key to verify the data's integrity.

This is proof that the data hasn't changed after the document was signed if the decrypted hash matches a second hash of the same data. If the two hashes don't match, we can assume one of the following likely scenarios. Either the data has been changed and is now compromised, or the signature was made with a private key that doesn't match the public key supplied by the signer, resulting in an authentication problem.

What about digital certificates?

A digital certificate is a digital document issued by a Certificate Authority (C.A.). It includes the public key for a digital signature and the identification connected with the key, such as an organisation's name. The certificate verifies that the public key belongs to a particular organisation. The CA serves as a guarantor. Digital certificates must be issued by a reputable organisation and are only valid for a limited period. They are needed to generate a digital signature.

PKI or PGP for digital signatures?

Why should you choose PKI or PGP when it comes to digital signatures?

PKI and the Pretty Good Privacy (PGP) encryption tool are used in digital signatures because they both lessen the security risks associated with transmitting public keys. They confirm that the sender's public key belongs to that person and that the sender is whom they claim to be.

PKI is a service framework for generating, distributing, controlling, and accounting public-key certificates. PGP is an asymmetric and public-key cryptography variant of the PKI standard. PKI relies on certificate authorities (C.A.s) to confirm and bind a user's identity to a digital certificate, whereas PGP relies on a web of trust. PGP allows users to pick whom they trust and which identities are verified. Users of PKI rely on trusted C.A.s.

The strength of the private critical security determines the effectiveness of a digital signature's security. It's hard to revoke a compromised key or confirm someone's identity without PKI or PGP, making it easier for hostile actors to impersonate people.

What are some of the industries that use digital signatures?


Digital signature technology is used in various industries to improve document quality and expedite procedures. The following are some examples of industries that use digital signatures:


The Government's Publishing Office publishes electronic budgets, public and private legislation, and congressional bills with digital signatures. Governments employ digital signatures to process tax returns, validate B2G transactions, approve legislation and manage contracts. Using digital signatures is subject to tight laws and norms for most government agencies. Many governments and businesses use smart cards to identify their people and employees. These are physical cards with a digital signature granting access to an institution's systems or buildings.

In Singapore, every government service is accessible through Singpass login. Singpass acts as the Certificate Authority, ensuring the security of the private key for every account. 


Digital signatures are used in healthcare to improve efficiency, data security, e-prescribing, and hospital admissions. The usage of digital signatures in healthcare must comply with HIPAA.


Digital signatures help manufacturing organisations speed up product creation, quality assurance, production improvements, marketing, and sales. The ISO and NIST Digital Manufacturing Certificates govern digital signatures in manufacturing (DMC).


In the U.S., contracts, paperless banking, loan processing, insurance documentation, mortgages, and more employ digital signature. The Consumer Financial Protection Bureau (CFPB) and the Federal Financial Institutions Examination Council (FFIEC) all employ digital signatures in this heavily regulated industry (FFIEC).

Banks fully adopted account openings and loan applications in Singapore through Singpass MyInfo. 


Bitcoin and other cryptocurrencies use digital signatures to authenticate transactions on the blockchain. They are also used to maintain bitcoin transaction data and to show ownership of cash or involvement in a transaction.

Tessaract Digital Signing

With Tessaract Digital Signing, you can generate documents pre-filled with customer data in just a few clicks, send it for signing and receive the signed copies all on Tessaract under two minutes. With signing with Singpass, you can also ensure the identity and authorisation of the signing party. Also, learn how Tessaract enabled That.Legal to achieve operational efficiency and agile growth through our case study.

Tessaract Digital Signing is available as a standalone product. Request for a demo today.

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Written by Pehon