Private equity firm Thoma Bravo, which has offices in San Francisco, said today that it has acquired IT security and compliance software developer Tripwire. Tripwire was based in Portland. Financial details of the acquisition were not disclosed. The buy represents and exit for Advanced Technology Ventures, Bessemer, BA Ventures, and IVP, the venture backers of the company. The acquisition comes after Tripwire filed for an IPO on the Nasdaq. Tripwire was advised by J.P. Morgan Securities LLC and Perkins Coie in the deal; Thoma Bravo was advised by Kirkland & Ellis.