What is a Digital Signature ? Recognizing Crypto-style Signatures

What is Digital Signature

In 1976, cryptography experts had proposed the idea of a Digital Signature. A year later, the forerunner of Digital Signature or digital signature was launched. What is a Digital Signature ?

If you are a fan of cryptography, you must know one of the cryptographic products called Digital Signature. Knowledge of Digital Signature is useful in innovation authentication and security of your transactions. Find out what a Digital Signature is, its functions, advantages, features, and methods in this article.

Definition of Digital Signature

What is a Digital Signature? The world of cryptography promises a future digital security system. Various alternative crypto security systems have been proven to increase work effectiveness in various fields. Digital Signature is a technical term in cryptography.

First you need to distinguish between Digital Signature and e-Signature. What is a Digital Signature? A digital signature is a mathematical code scheme used to certify digital documents. That is, a Digital Signature is a complex code used to ensure the authenticity of the document.

While e-Signature or Electronic Signature or electronic signature is a pattern of our signature, or a special symbol, or sound that we record or record digitally as a marker of the validity of the document.

So, the ‘digital’ emphasis on the term Digital Signature is not just a concept of digital space. A digital signature is not the same as a digitized signature (scribble), but refers to an authentication mark in the form of a mathematical algorithm code.

As a measure of document authenticity, a Digital Signature functions the same as a regular signature or an e-Signature. But of course, Digital Signature as a crypto system has a high level of security verification authentication.

Digital Signature cryptography offers a layered security system which is certainly needed in very important document transactions.

Digital Signature Functions as a Crypto System

What is the function of Digital Signature? Digital Signature fulfills at least 3 functions of a cryptographic security system, namely:

Authentication Function

The Authentication or recognition function allows the recipient to verify that the document was actually sent by the original sender. That is, the identity data of the sender corresponds to the data stored on the receiving system. This of course has an impact on determining the authenticity of the contents of the document.

Integrity Function

The Integrity function relates to the system keeping the data in its original form when sent. Digital Signature ensures that the data received is exactly the same as the data sent without any unauthorized changes that may occur during the sending process.

This secures data from possible data manipulation practices (such as insertion, modification, deletion, etc.) by other parties outside the sender and recipient.

Non-Repudiation Function

Manipulation is not impossible on the part of the sender. Digital Signature ensures that data is only sent by the sender and is definitely sent by the sender. That is, Digital Signature closes the possibility of denial of data transmission.

So as the owner of a Digital Signature, the sender also needs to be super careful in deciding to send data with a digital signature. Because once the document is received, there is no possibility of denying it.

Advantages of Digital Signature

Can you imagine a transaction to buy a piece of land? The legality of the land deed requires an official watermark, agency stamp, seller’s original signature, buyer’s original signature, notary public, PPAT and various other instruments.

Can you imagine a larger document transaction than that? What if all those devices were trimmed and leaving only one thing: Digital Signature.

This simple illustration can give you an idea of the advantages of Digital Signature that users can feel in one transaction. A source said using Digital Signature even saves a week faster than regular signing transactions.

  1. More efficient transactions. As can be seen from the illustration of the land sale and purchase transaction, Digital Signature can cut more than 50% of the transaction process flow.
  2. Safer transactions. Transaction records are stored and secured with a cryptographic system. Tracing and authentication are also done more securely and neatly than ordinary digital logging.
  3. Accepted as valid evidence globally. Digital Signature has been established in international standards (ISO) as a trusted and secure legitimacy device.

Features in Digital Signature

Digital Signature is one of the cryptographic systems that has brought the whole world to a great change. In 1977, the RSA algorithm was born as the first algorithm which was later used for Digital Signature systems.

Since then, Digital Signature was introduced as a public key infrastructure (IKP). In 2008, Digital Signature was set to become an ISO (International Organization for Standardization) standard for digital documents.

The features and methods that work in Digital Signature offer several advantages that other authentication systems cannot compete with. Here are 6 excellent features offered in Digital Signature:

  • Automatic Time Stamping

This feature provides an identification stamp of the signing of the document.

  • Built with Asymmetric Cryptography System

Digital Signature uses private key and public key algorithms to encrypt and authenticate data.

  • Checksum Features

Checksum can be understood as a data fingerprint in the form of a series of numbers and letters to compare the truth of the data sent and received.

  • Cyclic Redundancy Checking or CRC feature

Code feature to detect changes to raw data. A sort of post-signing recorder feature.

  • The existence of a Certificate authority or CA

A Certificate Authority is a third party that accepts, authenticates, issues, and maintains digital certificates. Certificate Authority helps avoid creating fake Digital Signature certificates.

  • Adanya Trust Service Provider atau TSP

TSP is a third party like CA. The task of the TSP is to validate the Digital Signature after it has been issued by the CA. TSP also has the role of recording and reporting Digital Signature validation in transactions.

Digital Signature Mechanism

As mentioned earlier, Digital Signature is built with an asymmetric cryptographic system. In simple terms, asymmetric cryptography is a cryptographic system that uses two different algorithms for the encryption and authentication process of data or also known as algorithms for private keys and public keys.

These two algorithms are paired as a single Digital Signature. Where one key, i.e. the private key is held by the sender, while the public key is kept by the receiver.

The pairing of these two algorithms is made possible by the presence of a hash function. The hash function works on the encryption or signing process by the sender and at the time of verification of the data received by the recipient.

In simple terms the process that occurs in signing by the sender is as follows:

  1. Reading messages with a hash function to get Message Digest.
  2. Message Digest is encrypted with a private key cryptographic algorithm (for example, an RSA algorithm) to obtain a Digital Signature.
  3. Digital signatures are required on documents.
  4.  The signed document is sent.

Messages that have been sent and reach the recipient require verification to prove the authenticity of the message. The process occurs as follows:

  1. The digital signature is described with the recipient’s public key. Result Description will generate Message Digest.
  2. The receiver reads the message with the same hash function as the sender. This process will generate a Message Digest which should be the same as the Message Digest described from the Digital Signature in step 1.
  3. If the results of the Message Digest step 1 and step 2 match, then the authenticity of the document and its security can be accounted for.

As a cryptographic product that has received ISO standardization, many major countries in the world have used digital signature systems for the validity of their documents.

Prospect Digital Signature

In addition to ratifying government documents, now the use of Digital Signatures has also been found in many banking transactions, intercompany transactions, buying and selling digital assets and other digital transactions that are very vulnerable to the possibility of data manipulation and falsification.

The digital document procession is still doubted by a number of parties because of the high possibility of manipulation and forgery. However, Digital Signature and various other cryptographic products are predicted to be a smart solution to this problem.

Plus, in the future, it will be impossible for the whole world to avoid digital transactions. From personal to global scale. Sending documents manually (physically) is somewhat riskier.

Digital Signature can maintain the integrity of digital transactions from the worst risks. This digital validation of documents offers storage efficiency and better utilization of natural resources and human resources. Digitally signed documents definitely don’t take up much space and are much more energy efficient.


Muhammad Zaki Fajrul Haq
Author: Muhammad Zaki Fajrul Haq

Follow me at @mzfajrulhaq (Instagram) or @ZakiFajrul (Twitter).

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