Private equity firm TA Associates has completed a majority investment in DigiCert Inc., a company that provides security services. Terms of the deal weren’t disclosed.

DigiCert, headquartered in London, Utah, provides authentication and encryption services to government agencies, financial institutions, medical institutions and other companies.

Boston-based TA invests in business services, communications, financial services, consumer, healthcare and software. The firm’s portfolio companies include Millennium Laboratories, MetroPCS Communications Inc. and e-Rewards Inc.

O’Melveny & Myers provided legal counsel to TA; while Goodwin Procter LLP provided counsel to DigiCert. William Blair acted as DigiCert’s financial adviser.