Legality and enforceability of electronic signatures in Thailand*

In 2001, Thailand adopted the Electronic Transactions Act, which recognized the legal validity of electronic signatures and set up the rules for their use. This Act does not establish clear tiers of electronic signature; however, it uses the concept of a “reliable” electronic signature and specifies the reliability criteria.

In Thailand, an electronic signature is a letter, character, number, sound, or any other symbol created in electronic form and affixed to a document to establish the association between a person and a document, identify the signatory, and show that the signatory approves the information contained in that document.

For an electronic signature to be valid, it must meet the following criteria:

1. The signing method is capable of identifying the signatory.
2. The signature reasonably indicates that the signatory approved the information contained in the signed document.
3. The parties used a reliable signing method, meaning that:
   • The signature creation data are linked exclusively to the signatory.
   • The signature creation data were, at the time of signing, under the exclusive control of the signatory.
   • Any alteration to the electronic signature made after the time of signing is detectable.

According to the regulatory authority, the Electronic Transactions Development Agency, the industry standard is to use PKI technology to ensure the reliability of the electronic signature.

However, according to the law, it is not the only possible way: a signatory can provide evidence to prove that other signing methods except PKI are reliable and satisfy the requirements of the Thailand laws.

The law does not directly answer this question. However, for an electronic signature to be valid, it must indicate that the signatory approved the information contained in the signed document. Therefore, any evidence demonstrating the person’s explicit or implied consent to use electronic signatures would positively impact the validity of that electronic signature.

As a general rule, in Thailand, information shall not be denied legal effect and enforceability solely because it is in electronic form.

The law also permits to use electronic documents and signatures to support your statements, comply with the requirements of the law, or provide as evidence if:

• The electronic document is accessible and usable for subsequent reference.
• The content of such document cannot be altered.
• The electronic signature complies with the requirements specified in the previous section.

When the court assesses the evidential weight of electronic documents and signatures, it pays attention to whether a reliable signature method was used, whether the completeness and integrity of the document were maintained, and how the signatories were identified during the signing process.

According to the law, a person is not permitted to use electronic signatures to sign any agreements or deeds related to the family law or inheritance law transactions, e.g., wills, adoption papers, inheritance documents, divorce certificates, etc.

Last updated: September 2024