The company, whose flagship product Posta is designed to send documents over the Internet in a secure fashion, raised $8 million in equity funding from some of the company's original investors, as well as a few new ones.
Original investors Draper Fisher Jurvetson and Sofinnova kicked in some funding, as did newcomers August Capital, Bessemer Venture Partners, and Adobe Ventures. The Adobe Venture fund is managed by Hambrecht & Quist.
August Capital's David Marquardt and Hambrecht & Quist's Standish O'Grady joined the Tumbleweed board of directors.
Tumbleweed received its second round of financing in the midst of a hot venture capital market for technology companies. According to a study by Price Waterhouse, VC spending for the second quarter reached a record $3.18 billion, with 70 percent going to technology-based companies.
Tumbleweed will use the money to hawk Posta, which launched in final version in June. Tumbleweed's investors are banking that Internet document delivery will be a high-growth market.
"In reviewing Tumbleweed Software's management team and technology, we have concluded that they will become the leader in this market," said August Capital general partner David Marquardt in a statement.
Meanwhile, a company spokeswoman said: "The company is thrilled to have David Marquardt and Adobe Ventures endorse Tumbleweed and its technologies with their investment, which will help the company get the word out about the value of Posta."