Symantec will buy the email encryption company along with data encryption firm GuardianEdge Technologies, which it will acquire for $70 million in cash. The acquisitions are expected to close during June.

Symantec will use the acquisitions to bolster its position in the encryption market, and will integrate the PGP key management platform into the Symantec Protection Center, which provides a set of security management dashboards for administrators. Both companies will be incorporated under the Enterprise Security Group within Symantec.

PGP inventor Phil Zimmermann founded the original company, PGP Inc., after he invented the PGP encryption product in 1991. Zimmerman sold the company to Network Associates in 1997, and it was subsequently sold again to a team of encryption experts in 2002, when it became PGP Corp.

PGP's defining characteristic was the Web of Trust, in which the authenticity of a certificate was guaranteed by a third party trusted by the recipient, effectively acting as an official introduction of one PGP user to another by that third, trusted user. This has since been developed to include multiple layers of trust, making it more compatible with the hierarchical certificate authority models found in other PKI implementations.

Perhaps one of the most significant points in PGP history was when Zimmermann became the target of a formal investigation by the US government, after the PGP encryption algorithm appeared outside the United States. PGP responded by publishing the entire source code of PGP, effectively making the algorithm available to everyone. The investigation was closed without further action.