DALLAS (AP) ¿ Digital security software company Entrust Inc. said Monday it agreed to be bought by an affiliate of the private investment firm Thoma Bravo LLC in a deal valued at $114 million. As part of the deal, Entrust's shareholders will receive $1.85 in cash for each Entrust share they hold. This represents a roughly 11 percent premium over Entrust's closing price last Thursday. The stock market was closed Friday. Entrust said its board has approved the deal, which allows the company to solicit alternative proposals from third parties during the next 30 days. Thoma Bravo said it has been in business for more than 28 years and manages about $2.5 billion of equity capital through a series of funds. It said it has completed 38 acquisitions in the software indusry in a dozen companies with total annual earnings of more than $600 million.