What Is Digital Signature ?

In this article, we will discuss the topic “what is digital signature?”. Also, we will look at, Certificate Authority, electronic signature, Public Key, etc.

It is a way to convince people that a digital communication is legit.

Definition of a Digital Signature

To avoid fake digital documents, digital signature makes use of cryptography.

Once the cryptography detects validity of documents, they are said to be legit. The sender is considered a sincere person and therefore cannot manipulate the data of the documents.

Encryption and decryption are done with the use of both private and public keys respectively. This is the concept of public key cryptography. Well, public keys are supposed to be shared while private keys are not.

The signing and verification of documents follows a due process. A hash is created and later encrypted using a private key. This is the signing process. On the other hand, the encrypted hash is decrypted while a new hash is established. If the two hashes rhyme, then the document is verified.

More Info On Digital Signature

Most times, digital signatures are used to explain how the technology of electronic signatures. But, both of them are two different things altogether.

However, the electronic signature is a representation of a signature with digital marks. Adobe Sign and Hello Sign are good illustrations. Whenever a public key cryptography is applied, some electronic signature tools may contain details of the digital signature technology.

Globally, digital signatures are also used to validate network connections across the internet. The government are also finding the idea interesting. In recent times, the U.S. Government Printing Office publish key documents together with public signatures to ensure they are valid.

Digital Signature Further Explained

A digital signature is also a mathematical calculation used to check how valid digital messages or documents are. With all the requirements met, a verified digital signature assures the receiver an authentic document which was not manipulated.

They have many use cases. Some of them are sharing software, easing financial deals, managing of contract and detection of fake messages. Their operations fits in with cryptography.  

All digital signatures use electronic signatures but not all electronic signatures make use of the digital signatures. There are countries that support the use electronic signatures. They include: Canada, South Africa, the United States, etc.

In most cases, digital signatures offers different phases of verification and safety to the messages coming from a risky media. The aim is to convince the receiver that the sent message is valid straight from the claimed sender. On a neutral ground, digital signatures are similar to locally written signatures. The only difference is that signatures written with the hands are easily manipulated than that of digital signatures.

They use cryptography mechanism, therefore should be treated with caution. They also make sure that senders are transparent enough and their private keys are undisclosed. Also, these transparent plans works in such a way that even if the private key is exposed, the signature is valid. Messages signed with digital signatures can take the form of a bit string such as electronic mail, contracts, or a message sent through other means of cryptography.

Operations of Digital Signatures

Each digital signature is different from the rest. They have companies like DocuSign that solves the issues encountered. The solution providers are expected to use mathematical approach to generate public and private keys. This process is known as PKI.

In the process of electronic signature, signatures are generated with the signer’s private key. This key is also protected by the signer. The mathematical approach acts like a message written in secret codes. It creates a hash to fit in with the already signed document, later the harsh is converted to codes. The output of this process is what we call the digital signature. Digital signature works with respect to time. Any change detected after signing results to an invalid digital signature.

Let’s take a look at real life application. Jane signs an agreement with her private key to sell some moments. The buyer will get the signed document and a replica of Jane’s public key. If the public key can’t convert the codes to human language, it is either there has been  change in the document or Jane is not the owner. It will be reported as fake immediately.

The PKI adopts the services of a Certificate Authority that is trustworthy. This is simply done to prevent a signature being tampered with. DocuSign meets up with the needs of PKI to enable a free and fair signature.

Origin of Digital Signature

In the past, there were two persons that guessed about digital signature plans as one that can be replaced through a unique way. There guess was very close anyways, there names were Whitfield Diffie and Martin Hellman. However, Ronald Rivest, ADI Shamir and Len Adleman later invented a set of rules known as the RSA. These set of rules could produce old digital signatures, they were not safe afterall. Lotus Notes 1.0 is a software that adopted the RSA set of rules and its marketing went global. It was the first to do so.

As time went on, other plans about digital signature were also developed. They were Lamport signatures, Merkle signatures and Rabin signatures.

After some years, Shafi Goldwasser, Silvio Micali, and Ronald Rivest became the first to strictly state the security measures of digital signature plans. They illustrated the ways the plans of digital signature could be opposed, they also displayed the GMR signature plans. This was the first plan that has successfully prevented a manipulation on a specific message. Their own method was accepted as the proper security measure for signature plans. Moni Naor and Moti Yung displayed the first plan that were replaced via a particular way, they were built on the basis of group of functions rather than limited ones.

Where can Digital Signatures be applied?

The world is evolving gradually, companies no longer associate with paper documents that use stamps or ink as signatures but rather they use digital signatures. They tend to convince people about the origin, identity and status of an electronic document. They also respect the idea of showing concerns and validation signers. The United States Government Printing Office (GPO) publishes budgets made via electronic means, public and private laws, and congressional bills that were signed digitally. Penn State, University of Chicago, and Stanford are also applying the same process in terms of student’s transcripts.

Reasons digital signatures are used :

Verification of Digital Signatures

Digital signatures can be used to check how valid the source of messages are. Some messages may have the details of the sender, but this alone doesn’t make the messages valid. Once it shows that private key of the digital signature is owned by a particular user, consider the message authentic. This is most important in the financial aspect. For instance, the branch office of a bank requested for change in account balance, if the source of the request is not verified, it’s best to decline the request.

Unity of Digital Signatures

In most situations, both the sender and receiver are supposed to be convinced enough that the messages were not tampered with. In many scenarios, the sender and receiver of a message may have a need for confidence that the message has not been altered during transmission.

One can change the way they code a message without being aware. Non-malleable can prevent this from occurring while others don’t. Generally, if you convert a message to computer codes, you automatically hide its details. For most cryptographic hash functions, modification of a message and its signature to create a new one with an authentic signature is impossible. So there’s no better approach to this issue. You can read further at collision resistance.

Sincerity of Digital Signatures

This is a very important reason for using digital signatures.

This means that , no one can deny an information after they sign it a long time ago. Also, nobody can forge a signature while using only a public key.

The above features depends non cancellation of private key while in use. One have to request for it before canceling a key-pair openly. Else, the private keys disclosed will put the owner of the key-pair in trouble. They need to do cancellation status check online through Online Certificate Status Protocol or certificate revocation list. This is similar to when a vendor checks the validity of a credit card after they deliver it . They usually discover theft of key pairs after they use the private key. Example signing a huge spy deal.  

Security Precautions adopted by Digital Signatures 

Storage of a Private Key on a Smart Card 

The cryptographic protocols of both public and private keys works on the basis on maintaining the secrecy of the private key. There are two disadvantages with storage and security of a private key on a computer, namely:

  • The limit the signing of documents to that particular computer system.
  • If the computer system is not safe enough, it equally affects the safety of the private key.

An option that is much safe is using a smart card as a storage medium. A man called Ross Anderson together with his students messed up the special design of smart cards. They made this design to enable the smart card function properly without manipulation.

Typically, while carrying out digital signature, they send the hash that they calculate from the document to the smart card. The CPU of the smart card signs the hash with the private key kept inside of it, and later returns the signed hash. However, a user must activate their smart card by inputting  a PIN code which offers a two-factor authentication. With this, they can set the private key to remain permanent in the smart card. Although it happens once in awhile.

In the case of theft, the thief cannot generate a digital signature without the PIN code. Thus, the security narrows down the PIN. To lessen the burden, it is hard to duplicate private keys that they create and keep in a smart card. Therefore, the owner may find out that the smart card is missing and officially cancels the certificate that matched. It is hard to detect duplicates in the case of a private key only secured by a software. Although they may duplicate it easily.

Assessment of Smart Card Readers Using A Different Keyboard

Some card readers have their own numeric keypad as it the tool needed for activation of a smart card. It is better than inserting a card reader to a PC and activating with the keyboard of that same PC. Card readers with their own numeric keypad should avoid the threat of customizing a PIN code via a keystroke logger. The level of proneness to manipulation of specialized card readers is relatively low and are often EAL3 certified.

The rest of Smart Card Designs

Smart card design is very vibrant and there are smart card plans which the make to avoid these particular problems. Although there is no proof of high security.

Assessment of Trusted Applications for Digital Signatures

A digital signature is quite different from a hand-written one because in the former does not allow signers to see what the sign. We are going to discuss further on it, read on. One can present what he or she wants to sign as a harsh code. They can now sign it with a private key. A hacker in control of the user’s PC can possibly substitute the application for his or her selfish interest. This could trigger a malicious act where users will be seeing the original signing background. But the documents presented are that of the hacker.

In order to avoid this situation, one can set up an authentication system between the user’s application and the signing application. The major aim of this is to enable two- factor authentication. For example, the signing application may want all their requests to come in digital form.

A Hardware Security Component Attached to a Network

A cloud-based digital signature is similar to a local except in the aspect of risk. To enable proper validation and security of signatures, governments, financial and medical institutions, and payment processors requests for more secure standards, like FIPS 140-2 level 3 and FIPS 201 certification.

What You See Is What You Sign

WYSIWYS (What You See Is What You Sign) is trying to tell you that the meaning of a signed message, that no one can change. It also means that a message cannot contain discrete information, which they will be display. This is after signing instead of surfacing during the signing process. WYSIWYS is a requirement for a legit digital signature.

However, the rising complexity of modern computer systems is making it hard to implement. Peter Landrock and Torben Pedersen were the persons that introduced the term WYSIWYS. They gave the name to explain some of the guidelines to delivering secure and valid digital signatures for Pan-European projects.

A digital signature technically makes use of a string of bits, and both humans and applications assumes that they know the meaning of what they sign. To give the bit meaning, one must transform it into an application and human understandable form. How do we achieve this? Just combine a hardware and software based processes on a computer system.

The problem is that the meaning of bits can change with respect to the processes used to transform the bits into a meaningful content. It is relatively easy to change the meaning of a digital document by making significant changes on the computer system. From a meaningful angle, what is under a signature remains unknown.

Comparison between Digital signatures and Ink-on-paper signatures

Anyone can duplicate an ink signature digitally or manually from one document to the other. But it requires a special skill to do so without gaining much attention. It is hard to make a duplicates of ink signature with facing a closer examination by professionals.

Digital signatures legally merge an electronic identity with an electronic document and thereby making duplication of the digital signature a difficult task. Paper-based documents often have the area for ink signature on the last page.

After signing, they may change the previous pages. In contrast, they can apply digital signatures to an entire document. In that case, if they alter any data on any of the pages, it will be obvious that it was under manipulation. You can also sign with an ink and number all the pages to practically achieve this.


  • RSA
  • DSA
  • EdDSA
  • RSA with SHA
  • ECDSA with SHA
  • ElGamal signature scheme as the predecessor to DSA, and variants Schnorr signature and Pointcheval–Stern signature algorithm
  • Rabin signature algorithm
  • Pairing-based schemes such as BLS
  • NTRUSign is an example of a digital signature plan that operates on the basis of hard lattice problems
  • Undeniable signatures
  • Aggregate signature – this a signature plan that supports the use of aggregates. For instance, given a particular number of signatures on specific number of messages from specific number of users. It is possible to sum up all these signatures into a single signature which has constant number of users. This single signature will convince the verifier that the specific number of users actually signed the particular number of original messages. A plan setup by Mihir Bellare and Gregory Neven may be applicable with Bitcoin.
  • Signatures with efficient protocols – are signature plans that hastens efficient cryptographic protocols such as zero-knowledge proofs or secure computation.

The theory and practical applications of digital signature

Regardless of legal protocols made by cryptographic mechanisms, most of the digital signature plans share the following aims:

  1. Quality algorithms: Some methods of public key are risky since the discovery of significant attacks.
  2. Quality implementations: The are suppose to carry out protocols in the total absence of errors whether good or bad.
  3. Users must properly implement the signature protocol in conjunction with their software.
  4. The private key must remain private: Once the disclose private key to anyone, that person has the full potentials to tamper with the digital signatures.
  5. The public key owner must be verifiable: A public key associated with Chris should come from Chris in the real sense. They use a public key infrastructure (PKI) to do this. Also the relationship between the public key and its users is testified by a certificate authority. For public PKIs in which anyone can request such an evidence, the possibility of bearing false witness is very significant. Commercial PKI operators have encountered a lot of generally known problems. This kind of error could lead to signing documents falsely and attributing documents to the wrong person. In contrast, private PKI systems are more expensive, but less easily weakened in this way.

More Information On The theory And Practical Applications Of Digital Signature

Once they meet the conditions above , then probably there won’t be anonymity in the messages, the sign digitally. Passing down laws legally cannot change what engineering is capable of offering in the real sense, though some such have not actually surfaced.

Companies that believe they can benefit from a PKI operation have continuously begged the legislatures. They also expect profits from the original or new technology which offers new solutions to old problems. These legislatures through their legal power have passed down laws or regulations in many areas such as authorizing, endorsing, encouraging, or permitting digital signatures and providing for their legal effect. The case in Utah in the United States must have preceded that of the states Massachusetts and California.

Other countries have also enacted laws or issued regulations in this area as well. The UN has held an active model law project for some time. These passing of legislative laws differs with location, it has equally grasped various expectations both positive and with the state of the underlying cryptographic engineering. It has ended up confusing almost everyone that has little or no knowledge of cryptography.

The limit this legislation by the use of technical criteria for digital signatures. This has also delayed features that engineering is willing to offer such as unified engineering position on cross communication, choice of methods, key length, etc.

Industry Criteria for Digital Signatures

Some industries have common cross communication criteria set for the use of digital signatures. The place these criterias between members of the industry and regulators. For example, the Automotive Network Exchange used in the automobile industry and the SAFE-BioPharma Association used for the healthcare industry.

Adopting separate key pairs for signing and encryption

Generally, any document with a digital signature is not illegal. This is because the already connect terms with the signer. Therefore, it is advisable not to use the same key pairs for encryption and signature respectively. With the use of the encryption key pair, a person can interact in coded languages. This does not mean that they sign all the messages sent.

Both sides can use their respective keys to sign a contract if and only if there is an agreement between them. Until then, they remain in disagreed with terms and conditions of a particular document. Once the complete the signature, the send the document over the link which was in code form.

The officially cancel any signing key when lost to lessen its negative impact to future transactions. Also, the should use a backup or key escrow to access documents. Especially those they did convert to codes when they misplace the encryption key. Backup is strictly for encryption keys unless stated otherwise.

Functions of Digital Signatures

People value digital signatures the same way with the local signatures. It is majorly in places like North America, the European Union, and APAC. They see it as legal entities in those areas like the ones above.

In addition, they use of it for financial transactions, email service providers, and software distribution. These are the most essential categories in terms of the authenticity and integrity of digital communications.

An industry-standard technology achieves this. The technologist call it public key infrastructure.

Operations of Digital Signatures

We have digital signing solution providers such as Zoho Sign that will generate two keys through a mathematical approach. The keys are both private and public. Once the sign a document digitally, the create a cryptographic hash automatically.

The further convert it to a code with the help of a private key that belongs to the sender. Also, the keep this key in a safe HSM box. Then, the attach it to the document and send it out together with the public key that belongs to the sender too.

The recipient can reconvert the code back to a human language using the sender’s public key certificate. Another cryptographic hash created on the receiver’s side.  

The compare the two cryptographic hashes and if they are similar, the document is authentic.

What Interest People about Digital Signatures ?

Meaning of public key infrastructure

It is a software and hardware that makes the management of digital signatures possible. In the case of PKI, there is a presence of both private and public keys that occurs in pairs. The private key is a personal key the use to carry out electronic signature. In contrast, the make the public key available and validator can use it.

With the records, it has many functions. The rest are enforcement of the Certificate Authority (CA), a digital certificate, end-user enrollment software. They also enforce the facilities used for managing, renewing, and revoking keys and certificates.

Meaning of a digital certificate

It bears the public key and as well notes down the identity of the key owner. Digital certificates are usually provided by trusted authorities and they function for limited period of time. The certificate authority will act as the warranty provider throughout.

The difference between a digital signature and an electronic signature

The digital signature part of electronic signatures overshadows many other types of electronic signatures. This part is very necessary for electronic signatures. They are also similar to other parts of electronic signatures in terms of giving one the chance to sign and validate documents. However, there are differences between the two in terms of technical implementation, geographical use, legal and cultural acceptance.

For eSignatures, the application of digital signature methodology differs. It all depends on the countries that adopts their public laws such as the United States, United Kingdom, Canada, and Australia. It also depends on countries that accepts their ranked personnel and low standards such as the European Union, South America, and Asia. However, some companies prefer unique standards that rely on digital signature protocols.

Creation of Digital Signatures

Companies like the DocuSign makes digital signatures an easy task, they create eSignature. Their operations are based on digital signature protocols. They also partner with the right Certificate Authority to ensure reliable digital certificates. They serve as a medium for sending and signing documents across the internet.

Sometimes they demand of you to provide additional details, or limitation to whom and how you send documents. It all depends on the type of Certificate Authority that is use. The interface of DocuSign will guide you throughout and makes sure you don’t miss any step. You must validate any document sent through your email first. After that, you can proceed to fill an online form.

Definition of Public Key Infrastructure (PKI)

It enables a lot of things but its main focus is the creation of digital signatures. In the case of PKI, there is a presence of both private and public keys that occurs in pairs. The private key is a personal key the use to carry out electronic signature. In contrast, the public key is publicly available and validators make use of it.

It is on record that it has many functions. The rest are enforcement of the Certificate Authority (CA), a digital certificate, end-user enrollment software. They also enforce the facilities used for managing, renewing, and revoking keys and certificates.

Meaning of a Certificate Authority (CA)

The define Certificate Authorities as third-party entities that issues digital certificates. The public also accept it. They are in charge of safeguarding private and public keys. The must reach an agreement on the basis of Certificate Authority. Digital signatures cannot function without the public and private keys. Both keys are of great importance as they prevent forging of documents or criminal act of any kind. There is need for conviction while signing a document to avoid problems.

In some cases, DocuSign can serve as the Certificate Authority. Especially, if the make signatures via the DocuSign Express Digital Signature. One can design his or her own certificate authority to serve as an option using the DocuSign Signature Appliance. However, it doesn’t stop one from reaching the benefitting features of DocuSign cloud services used to handle transactions. DocuSign encourage other outstanding Certificate Authority as well as some areas. Examples are OpenTrust and SAFE-BioPharma

Reasons for using digital signature

The use Digital signature to prevent faking of documents or manipulation after they sign it. Over the years, the bring eSignature standards to existence on the basis of digital signature methodology. The use of PKI technology- based local standards and collaboration with a trusted certificate authority. This ensures that the adopt and implement eSignature in every traditional market.

What digital signature solutions does DocuSign offer?

You can automatically control and manage all the digital operations via signatures based on DocuSign. This is possible due to business potentials DocuSign create as one complies with the level of local and industry eSignature. In the EU, DocuSign issues all the forms of signature under the operation of eIDAS. They are: EU Advanced Electronic Signatures (AdES) and EU Qualified Electronic Signatures (QES).

Whether eSignatures, which is on digital signature technology base, they can enforce it legally or not legally.

Of course they can enforce it legally. Just like when the EU enacted the EU Directive for Electronic Signatures in late 90’s. Later on the United States enacted the Electronic Signatures in Global and National Commerce Act (ESIGN). They both validate documents and contracts that the sign with electronic signature. Just like contracts based on paperwork. Electronic signatures have used a lot of times ever since.

Recently, people respect the U.S. or EU as subsequent legislation and people obey the rules by many countries. Their main focus being on the EU regions. In addition, digital signature method has helped many industries to continue to comply to rules set out by their owners (e.g. FDA 21 CFR Part 11 in the Life Sciences industry). Recently, the European Union has accepted the regulations of the Electronic identification and trust services (EIDAS). This shows a positive impact of the rules made specifically by countries and industries.

Overview of a digital certificate

The Certificate Authority (CA) are responsible for giving a digital signature certificate. It serves as the warrant issuer. It highlights the identity of the group or individual in charge of the public key it holds. The aim of the certificate is just authentication. The need the digital for the generation of a digital signature. They are valid for a few period of time and a reliable authority must give it.

See the List of things to learn.
  1. Blockchain Technology
  2. Defi
  3. NFTs
  4. DAOs
  5. Crypto
  6. Web 3.0
  7. Altcoin Tokenomics
  8. Metaverse
  9. Smart Contracts

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