Looking to expand its security appliance offerings, IronPort Systems plans to acquire PostX, a vendor of e-mail encryption software.The all-stock transaction is expected to close within the next "five or six weeks," said Liz Landis, an IronPort spokeswoman. Specific terms of the deal were not disclosed, but PostX shareholders will receive about 7 percent of the combined company\u2019s stock as a result of the deal, Landis said.PostX\u2019s software can be used to deliver encrypted e-mail to a user\u2019s mail box without the use of any special client software to decrypt the message.When the acquisition is completed, PostX\u2019s 60 employees are expected to be relocated to IronPort\u2019s San Bruno headquarters, Landis said. No layoffs are expected as a result of the acquisition.IronPort will sell PostX\u2019s e-mail encryption software under the PostX Secure Envelope brand. Founded in 1999 and based in Cupertino, California, PostX counts the U.S. Postal Service, Visa USA, and Charles Schwab & Co. amongst its customers.-Robert McMillan, IDG News Service (San Francisco Bureau)Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.