What is a Digital Signature?

In today’s world, digital technologies play a crucial role in various spheres of life, transforming traditional methods of interaction and communication. One of the most critical aspects of this digital transformation is digital signatures. A digital signature is a modern way to confirm the authenticity of documents and ensure their security in electronic format. It has become integral to office work, legal relations, and electronic document management, providing both convenience and information protection. In this article, we will look at what a digital signature is, how it works, its benefits, and how to control its use in companies.

What is a digital signature?

A digital signature is a cryptographic technology needed to ensure the security of online transactions and messages and confirm their authenticity. It confirms the immutability of the information sent to the user and the authenticity of the sender.
An electronic signature is a mandatory part of an electronic document. In other words, electronic records are valid when signed with an electronic signature.
In cases defined by the State, an electronic signature has the same validity as a handwritten personal signature.

What is the advantage of a digital signature?

A digital signature has many advantages, making it extremely useful in today’s digital world. Here are the main ones:
1. Confirmation of authenticity
A digital signature ensures that a specific person or organization has signed the document. This helps to avoid document forgery, message fraud, and fraud.
2. Data Integrity
A digital signature ensures the integrity of the document. If any changes are made to the document after signing, the signature becomes invalid, which indicates a possible falsification of the document.
3. Irrefutability
The signatory cannot deny that the document was signed. This is especially important in a legal relationship where confirming a particular person has signed a specific document may be necessary.
4. Simplify processes
Digital signature significantly simplifies and speeds up the process of signing documents. Instead of a physical signature that requires a human presence, an electronic device is sufficient, saving time and resources.
5. Lower cost
Using digital signatures reduces the cost of paper, postal services, and document archiving, as many processes can be fully converted to electronic format.
6. Improved security
Digital signatures use cryptography, making them more secure against unauthorized access and forgery than traditional signatures.
7. Compatibility and compliance with standards
Digital signatures comply with international standards and can be used in various legal systems, facilitating international cooperation and electronic transactions.
These advantages make digital signatures an essential tool for organizations and individuals seeking to conduct business efficiently and securely in the digital space.

What does a digital signature look like?

A digital signature is a unique set of characters created using cryptographic methods. Visually, a digital signature can look like a set of random letters, numbers, and special characters in a text string. For example, it might look like this:
a1b2c3d4e5f6g7h8i9j0klmnopqrstuvwxyz
However, a digital signature is not visible in the usual format, such as a manual signature on paper. Instead, it is embedded in the electronic document that will be signed. When verifying a digital signature, special software uses asymmetric encryption to ensure that the document was signed by the person who indicates it and that its content has not changed.
It is important to note that in order to use a digital signature, you need a special key (for example, a personal electronic key or certificate) issued by authorized bodies. This key ensures the security and uniqueness of the signature. 
In the case of using an eSign, visual design can also be used, for example, a stamp with the word “Signed”, but this is usually an addition to the digital signature itself, which remains behind the scenes for the user.

Features of digital signature in Belarus

An electronic digital signature (eSign) is a set of characters activated using a specialized electronic key. This key has a specific validity period and is kept by authorized persons who can sign electronic documents on their behalf or behalf of the company. Externally, the eSign key resembles a flash drive and is connected to a computer via a USB port for sending electronic documents.

In addition, there is a mobile digital signature where the private key is stored on the phone’s SIM card. Signing documents using a mobile digital signature does not require a computer connection. To work with a digital signature from a mobile device, the SIM card technology must support working with eSign. In this case, signing is done by exchanging SMS messages and entering a PIN code. 

In Belarus, users can get a mobile eSign certificate for one to three years from A1 and MTS telecom operators. This allows them to sign tax returns directly from their phones, for example. A mobile digital signature is also used to identify users on the public services portal.
The eSign can be stored on a cloud server for electronic document management. 

The decryption of a digital signature: keys

Asymmetric encryption technology, which includes a private key (Private key) and a public key (Public key), is usually used to form a digital signature. 
The private key is known only to the certificate owner and cannot be calculated, even if all the information in the public key is available. 
The public key is used to verify the authenticity of a specific user’s signature on an electronic document. Note that the private key is used to encrypt an electronic document, while the public key is used to decrypt it. 
Special software binds private and public keys. 
A public key certificate is an electronic document issued by an electronic document management service provider. 
It contains information about the validity period and confirms that the eSign belongs to a specific person. 
In Belarus, an eSign certificate can be obtained remotely and personally at the National Center for Electronic Services and its branches.

What permissions does a digital signature user have?

The certificate attributes determine the authority of the digital signature owner. An attribute certificate certifies the relationship between the owner of a personal digital signature key and a person who can sign electronic documents using a digital signature.
The attribute certificate is used with the public key certificate in electronic document management.
The attribute certificate contains information about the following:
1. a person authorized to sign documents with a digital signature.
2. the company that granted this authority.
3. authority to sign a specific electronic document.
The attribute certificate is required:
1. companies where employees sign electronic documents on behalf of the company and have a digital signature issued on behalf of the company.
2. in cases of transfer of authority to sign electronic documents to other persons.
At the National Center for Electronic Services, you can obtain an attribute certificate, like an open certificate of an electronic digital signature key. Both types of certificates can be obtained simultaneously.
The attribute certificate is also used in Belarus for reporting to the Social Protection Fund of the Population to provide access to the software that the Fund offers to social contribution payers. 
In addition, the attribute certificate is used in Belarus to participate in e-procurement and exchange electronic consignment notes.

Who can digitally sign documents?

Any person with a digital signature can use it to sign electronic documents. In a company, documents are signed on its behalf by the manager or employee who is entrusted with the right to sign.
Individual entrepreneurs and individuals also have the opportunity to use digital signatures to sign electronic documents for their professional activities and personal needs, compile statistical reports and tax reports, and submit documents to the Social Protection Fund, Belgosstrakh, and customs authorities.
Companies can exchange electronic invoices of the established type, signed with a digital signature, as well as other electronic documents, such as contracts and acts of work performed.
Individuals can use digital signatures to sign credit and other contracts.

Can I change documents that are digitally signed?

A digital signature is generated using a private key in a specialized program that generates immutable characters. This confirms the integrity of the electronic document. The public key of the digital signature allows the recipient to identify the document’s author. After signing, the document remains unchanged. The recipient’s device is used to decrypt the electronic document. If the document is signed with a valid digital signature, it is recognized as complete and authentic.

How to control the use of digital signatures

Monitoring the use of a digital signature includes several areas:
1. Registration and accounting of certificates
All digital signature users must complete the registration procedure and receive the appropriate certificate. Use registries to track active certificates and their status.
2. Monitoring user actions
Keep a record of all operations related to using a digital signature. This may include who, when, and what documents were signed.
3. Audits and inspections
Conduct periodic audits of the use of digital signatures. This will help you identify unauthorized actions and ensure that the eSign is used per the established rules and procedures.
4. User training
Ensure that employees know the rules for using digital signatures and possible risks. Conduct security and privacy training sessions.
5. Use of access control systems
Configure access and authentication rights for users to restrict access to the digital signature function only to authorized persons.
6. Renewal and revocation of certificates
Ensure that certificates are updated promptly and those that should no longer be used are revoked (for example, due to loss or compromise).
7. Encryption and critical protection
Protect the private keys to create a digital signature using encryption and hardware (such as tokens or smart cards).
8. Creating security policies
Develop and implement internal policies regarding digital signatures, including procedures for rejecting and verifying unauthorized use.
Digital signature control and management techniques help minimize the risks associated with their use and ensure trust in electronic documents and transactions.