Security messaging firm Tumbleweed has paid out $38.5 million for anti-spam firm Corvigo.

The deal will give Tumbleweed the rights to Corvigo's technology and access to more than 20 distributors across the US.

Corvigo is best known for its Linux-based anti-spam appliances, which Tumbleweed said would add to its range of secure internet messaging applications.

Under the deal, Tumbleweed will paid $3 million in cash and issued 4.7 million shares to acquire the Palo Alto-based company.