The firm recognised the need to increase the security of its messaging systems after a review of its existing security strategy.
The review was conducted in the light of Ponemon Institute research showing 70% of UK organisations suffered a data breach in the past year.
The firm was further prompted by clients' policies requiring the secure transmission of sensitive information to third parties.
Peter Birley, IT director at Browne Jacobson, said the Universal Gateway E-mail system from PGP will enable the firm to comply with all client and regulatory requirements as well as the ISO 27001 standard for security management.
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The system, chosen for PGP's experience in the legal sector, will enable Brown Jacobson to secure communications with clients using gateway-to-gateway encryption, Peter Birley said.
The firm can secure e-mail communication with large groups of customers, partners, experts and witnesses using clientless e-mail encryption provided by PGP's Universal Web Messenger software.
The firm plans to extend the system across other applications.
"We see our work with PGP as an investment not just in our communications strategy, but also in our overall IT security infrastructure, said Birley.