Add a layer of security to your systems and services, including your document signing processes, by requiring your customers and users to authenticate themselves with a code sent to their mobile phone.

Two-factor authentication

The conventional way to log in to a web service is with a username and password. These are both things the user knows, so it only counts as single-factor authentication. Since these can be compromised, it is more secure to require an additional authentication factor, typically something the user possesses (a physical device like a mobile phone) or a biometric identifier like a fingerprint. PIN by SMS became a widespread method of two-factor authentication because almost everyone has a mobile phone.


One of the easiest ways to gain additional assurance about the identity of someone online is to send a code to their mobile phone. They will then need to enter that code in order to complete an action that requires additional security, such as logging into a service, resetting a password or opening a protected document. This code is sometimes referred to as a One Time Password (OTP) because in most cases it can only be used once and has a limited duration of validity.

Geographical coverage

Scrive can send PIN by SMS codes to mobile phones in over 80 countries. For several other countries, some restrictions may apply, typically a pre-registration process to enable the service in a given country.

Signing agreements

PIN by SMS is an integrated feature in eSign, Scrive’s electronic signature service. When sending a document for a signature, you can require the signing party to authenticate at three different stages of the signing process:

  • To view the document (Authenticate to view)
  • To sign the document (Authenticate to sign)
  • To view the document after it has been signed and archived (Authenticate to view archive)

Requiring the signing party to authenticate to sign (using PIN by SMS or another supported authentication method) results in an electronic signature on the Advanced level according to the eIDAS Regulation.

Integrating PIN by SMS

The Scrive eID Hub is an API that makes it easy to integrate PIN by SMS authentication into your own services and systems. eID Hub gives you a single point of access to all the offerings in Scrive’s growing suite of eIDs and other digital identity services. Scrive supports you throughout the integration process, from testing to post-implementation support.

Frequently asked questions

What is two-factor authentication (2FA)?

Authentication that combines any two of the following three factors: 1) something you know (like a password), 2) something you have (like a mobile phone or bank card) or 3) something you are (biometric data like a fingerprint).

What is a One Time Password (OTP)?

An authentication code that in most cases can only be used once and has a limited duration of validity. PIN by SMS is a typical example of OTP.

Is PIN by SMS supported in every country?

Scrive can send PIN by SMS codes to mobile phones in over 80 countries. For others, some restrictions may apply.

Can you sign a document with PIN by SMS?

Strictly speaking, when you sign a document with a code sent to you by SMS, the function of the code is not to sign but to provide additional assurance of your identity. 

Our eIDs

We are continuously updating the eID Hub with expanded coverage and new technologies to support your business.

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Learn about Scrive’s eID offerings

Find out how to offer eID in your own services or in your Scrive eSign account.