In full recognition of the importance of data security for businesses of all sizes, Tradelink has set up a wholly-owned subsidiary, Digi-Sign Certification Services Limited, to provide customers with security solutions and services supporting electronic transactions and applications.

Digi-Sign is the first commercial company certified as a recognized certificate authority in Hong Kong under the Electronic Transactions Ordinance. Through the issuance of digital certificates to authenticate and validate the identity of certificate holders, Digi-Sign has helped to enhance the security of e-commerce and provided customers with a secure platform to conduct online transactions.

Since commenced operations in 2000, Digi-Sign has issued over 1,000,000 digital certificates, for use in the Government Electronic Trading Services and various e-commerce applications on which 'zero faults' have been recorded. Since 2004, Digi-Sign has been accredited ISO9001 certification, as recognition that its quality service is of international standard.

Besides providing digital certification services, to cope with the rapid development and growing popularity of online banking services, Digi-Sign has developed effective solutions for secure online banking transactions. In recent years, Digi-Sign has further extended its business to online / mobile security solutions supporting identity management (IDM) for mitigating identity fraud and as effective mechanisms to address personal identity-related regulatory requirements on financial activities. A number of leading banks and financial institutions in Hong Kong have adopted the IDM solutions provided by Digi-Sign.