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eSignature Legality Guide

eSignature Legality in Mexico

Mexico has no uniform law that governs the validity and legal effects of e-signatures. E-Signature legality is governed by multiple applicable laws and regulations set out by various legal bodies.


Mexico does not have a general "umbrella" type of law that governs the validity and legal effects of all types of electronic signatures. Conversely, rules incorporated in different laws and regulations may apply to the use of electronic signatures, depending upon the nature of the transaction (e.g., labor, commercial, tax, etc.).1

Under the Mexican Commercial Code, electronic signatures should be considered valid and will produce legal effects as long as the electronic signature creation method chosen by the parties is found to be appropriate for the purpose for which the data message was generated or communicated. Namely, the Mexican Commercial Code recognizes the following categories of e-signatures:

1. Electronic Signatures: Usually known as "Simple Electronic Signature"(SES)2

2. Advanced or Reliable Electronic Signatures (Firma Electrónica Avanzada o Fiable): Usually known as "Advanced Electronic Signature" (AES). An e-signature is considered as an AES if the following requirements, set forth in Section 97 of the Commercial Code, are met:

a) The signature creation data is, within the context in which the signature is used, linked exclusively to the signatory.

b) The signature creation data is, at the time of signing, under the exclusive control of the signatory and of no other person.

c) Any alteration to the electronic signature, made after the time of signing, is detectable; and

d) Any alteration made to the information (to which e-signature relates) after the time of signing is detectable

3. Advanced Electronic Signatures, supported by Digital Certificates issued by government approved Certification Services Providers (CSPs): In the international arena, this technique is known as "Qualified Electronic Signatures" (QES). QES are supported by a Digital Certificate issued by a handful of Certification Service Provider (CSP), which has been authorized to operate as such by the Ministry of Economy.

When it comes specifically to the validity under civil and mercantile agreements, if an e-contract is executed between two companies using an electronic signature technique or method, such e-contract agreement will produce legal effects.3 If at some point the parties need to present such e-contract as evidence in court, the court is mandated by law to admit such e-contracts as evidence and to provide such agreement with evidential weight.4

In the assessment of evidential weight by the court, regard shall be made, fundamentally, to the reliability of the method in which the e-contract and the corresponding e-signature was generated, stored, communicated, and maintained.

There are a couple of court precedents which have considered that an e-signature method must be considered valid as long as it is reliable (or it was generated through a reliable method for creating e-signatures). According to these principles, a reliable e-signature is the one that meets the requirements set out above for AES. 

Before such precedents were issued, courts used to consider Qualified (Certified) Electronic Signatures were more reliable than other electronic signature techniques.

However, under current precedents, an SES may be able to pass a reliability test and be ruled as an Advanced Electronic Signatures (AES), if the technology allows an SES to cover all mandatory requirements set out by section 97 of the Commercial Code.


Are there certain documents that cannot be e-signed in Mexico?


For some types of documents, parties may need to satisfy additional formal requirements under Mexican law, such as formalization before a public notary. Transactions that shall necessarily be completed before a public notary include real estate property transfer contracts, marriage contracts, powers of attorney, and the articles of incorporation of civil and mercantile companies.

Also, for the following types of documents, it may be advisable to perform a more detailed risk assessment before using electronic signatures: 

  • Promissory notes, guarantees, guarantees provided by co-obligators and other documents considered as negotiable instruments under the General Law of Negotiable Instruments and Credit Transactions (GLNICT): While GLNICT does not prohibit the use of electronic signatures, original documents are necessary to sustain the credit right consigned therein;
  • Mortgage or guarantor agreements. In general, agreements that needs to be granted before a Public Notary (i.e., sale of real estate property): Again, Civil Code does not prohibit the use of electronic signatures, but it is not a standard practice for Public Notaries to conclude such transactions through electronic means;
  • Under labor laws, only QES are equivalent to wet signatures. Documents executed through other techniques would be acceptable by a labor court, but additional supporting evidence would be required (for instance, to offer an expert witness). Certain labor documents may be signed through SES, such as compensation receipts. 
  • Tax Returns and other tax documents are usually not valid if concluded through a simple electronic signature. A specific QES model developed by the Tax authorities (Tax Law Art 17-D) are required for this purpose. This QES model is known as "e.Firma".
  • Litigation documents. For these documents, the Supreme Court of Justice has created its own QES scheme, under General Joint Agreement number 1/2013 of the Supreme Court, the Electoral Tribunal and the Council of the Federal Judiciary, regarding the Certified Electronic Signature of the Federal Judicial Power and the electronic files. This QES scheme is known as FIREL. 
  • Civil status acts, including recognition of children, adoption, marriage, divorce, death, and presumption of death, guardianship or legal capacity to administer property: The law usually requests the presence of the interested parties to execute related documentation, or else the granting of a power of attorney which must be certified by a Public Notary.


Does local regulation govern the use of digital IDs and/or certificates for e-signatures in Mexico?


Mexico has not issued regulation governing Digital IDs yet. 

With regard to certificates related to e-signatures, there are at least 4 regimes governing such certificates: a) Commercial regime, administered by the Economy Ministry; b) Tax regime, governed by the Mexican Tax Administration Service (SAT); c) Public Servants Regime, administered by the Public Functions Ministry (SFP) and; d) Judiciary regime, administered by the Supreme Court of Justice (SCJ). In the last 3 regimes, the corresponding authority acts both as issuer and of entity that relies on the certificate. For instance, tax payers’ e-signatures would be accompanied by a certificate issued by Tax authorities; public servants’ e-signed documents would attach the corresponding e-certificate issued by the SFP, and individuals filing electronic writs in connection with a trial would attach a certificate issued by the SCJ. 

In the case of the commercial regime, the Ministry of Economy has issued regulation in order to authorize private entities to act as CSPs. In order to become a CSP, a company need to obtain registration. For obtaining registration, CSP must evidence that they satisfy certain IT infrastructure, security, and human resources requirements. Currently, there are around 7 companies authorized to act as CSPs for commercial matters. 

CSPs are governed by the Commercial Code and its implementing regulations (Articles 100 to 113). In addition to providing issuance and certification of e-signatures services, they are authorized to provide other services, including a popular service named “Certificate of Conservation Service” (Servicios de Constancia de Conservación). Certificates of Conservation are issued under Mexican Official Standard (NOM-151-SCFI-2016, published on March 30, 2017. This Certificate allows a court to trust that a document has not been modified since the moment in which the certificate was electronically stamped in the electronic document.


Does local law provide certification bodies / trust services that users of e-signatures should be aware of in Mexico?


Please see our comments in question 3 above in connection with CSPs.



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*DISCLAIMER: The information contained in this guide is for information purposes only, provided as is as of the date of publication and should not be relied upon as legal advice or to determine how the law applies to your business or organization. It is recommended that you seek guidance from your legal counsel with regard to law applying specifically to your business or organization and how to ensure compliance. OneSpan does not accept liability for the contents of these materials or for third parties materials.

Last updated: November 2020