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An electronic signature, or e-signature, is a digital method for signing documents and authenticating the identity of the signer. It serves as a legally recognized way to provide consent or approval on electronic documents, eliminating the need for physical paper and ink signatures. A valid e-signature assures recipients that the document originates from a known source and has not been tampered with.

E-signature services offer several advantages, including increased productivity, enhanced security, and environmental sustainability. These benefits are available at your fingertips, accessible anytime, anywhere.

We offer two distinct e-signature services tailored to meet various needs:

  1. Adobe Acrobat Sign: Ideal for individuals or small teams that need to sign single documents.

  2. Adobe e-Signature (Adobe Sign): An extension of Acrobat Sign, this service is suited for more complex signing scenarios involving multiple signers, multiple documents, and the need for managing the entire signing process.

The following table can help you decide which e-signature service best matches your use cases.


Acrobat Sign

Adobe Sign

Number of Documents


≧ 1

Number of Signers

≧ 1

≧ 1

Number of Document Templates


≧ 1

Signing Process Management



e-Signatures involve a four-step process: preparation, signing, tracking, and storage. The sender places signature fields on the document, and signers prepare a signature for use.This preparation step also verifies the signer's identity and generates a pair of encryption keys.

The e-signature assures the document's integrity and is usually stored in the cloud for easy access.

e-Signature is legally binding.  The Electronic Transactions Ordinance (Cap. 553) (ETO) enacted in January 2000 and updated in June 2004, provides the legal framework for the recognition of electronic records and signatures, giving them the same legal status as their paper counterparts.

The ETO recognizes two different types of signatures that have the same legal effect as a physical signature: electronic signatures and certificate-based digital signatures.  Both electronic and digital signatures are recognized as having the same legal status as a handwritten signature as long as the requirements under the ETO have been satisfied.  However, unlike ordinary electronic signatures, certificate-based digital signatures are granted a statutory presumption as to their veracity and authenticity if they are supported by a certificate issued by a recognized certification authority (CA).

Under the ETO, a digital signature must be

  • supported by a recognized certificate (i.e., a digital certificate issued by a recognized certification authority)
  • generated within the validity of the recognized certificate
  • used in accordance with the terms of the recognized certificate

The Government Chief Information Officer maintains an online public record of each recognized certification authority.

No registration is required for using Acrobat Sign.
Adobe Sign is also currently available without registration, although this may change in the future.

Both Acrobat Sign and Adobe Sign are currently free.
Any change in the charging policy will be announced on this ITO website.

HKBU signers are identified by their HKBU Single Sign-On (SSO) ID and authenticated through the SSO service.
Non-HKBU signers are identified by their email addresses.

e-Signatures can be verified using a signature panel that provides various details, such as the document's validity and the certificate's validity, ensuring the document's integrity.

For both Acrobat Sign and Adobe Sign, a sender can set a signing password that the recipient must enter to access the document. Acrobat Sign does not offer post-signing confidentiality features, while Adobe Sign offers this through its non-cloud client-side app, GigaSign.