What consitutes a digital signature?

Basically, the definition of digital signature is similar to that of handwriting, which is used to confirm a promise or commitment, and is unable to be withdrawn afterwards. Digital signature does not require ink and paper; instead, it attaches the identifying characteristics of the signer to a commitment.

A digital signature is one form of electronic signature.

A digital signature is created on the basis of public-key cryptosystem (“RSA”):  It is prerequisite for each user to have one key pair consisting of a public key and a private key. Specifically, the private key is one of the key pair used in the asymmetric cryptography to create a digital signature; whereas the public key (also a part of the key pair used in the asymmetric cryptography) is utilised to verify the digital signature created by the corresponding private key in the key pair. 

Via such method, those who obtain the initial data message and public key of the signer can determine the followings:

• The aforementioned transformation is created by the correct private key corresponding to the public key in the same key pair;
• The integrity of the content of data messages since the implementation of the aforementioned transformation.

When to use digital signatures?

In regards of normal written documents, in case it is provided for by law that such documents need a signature in order to be deemed valid, a direct signature on the document shall be required.

However, where it is mandatory for a data message to have a signature, the data message must be signed with a digital signature.

In the event where a document is required by law to be stamped, such document must be signed with the digital signature of the person who is competent to manage and use the seal in compliance with provisions of law; and such digital signature is guaranteed safely.

Digital signatures are commonly used in electronic commercial transactions such as: customs, tax declaration, online purchases, etc.

Legal value of digital signatures

Electronic documents signed with digital signatures provided by competent authorities shall have the same legal validity as the printed, signed and sealed documents. In order to guarantee the validity of a digital signature, the following conditions on secure electronic signatures must be met:

• The digital signature is created during the effective period of the digital certificate and inspected by the public key recorded on such digital certificate.
• The digital signature is created by using the private key corresponding to the public key recorded on the digital certificate granted by competent organizations.
• The private key is known only to its proprietor being the signer at the moment of signing.
• The private key and contents of the data message are attached only to the signer upon signing such data message.

Competence to grant digital signatures

Organizations and individuals may utilise digital signatures for business activities or to satisfy internal demand and not for trading.

Enterprises shall apply for digital signatures at different competent authorities depending on each distinctive use purpose. According to provisions of law, the organizations competent to issue digital signatures to organizations and individuals using such signatures for business purposes are the ones providing the service of public digital signatures. 

During operation, if enterprises and individuals modify the initial registration information, owners of digital signatures must send a notice of such change to the digital signature granting organizations to update accordingly.

PLF Law Firm