Net infrastructure firm VeriSign has bought security intelligence firm iDefense for $40m in cash. iDefense's 45 employees will join VeriSign in a move designed to bolster its managed security services offering with proactive threat warning and security remediation advice.

iDefense is best known for its controversial vulnerability contributor program, which rewards hackers for advance notification of unpublished vulnerabilities or exploit code. It's not immediately clear if the program will continue post acquisition.

VeriSign's rivals in the managed security market include Symantec and Cybertrust, both of which came into the market niche through acquisitions, and Counterpane. In a statement, VeriSign said revenue and earnings contribution from the acquisition wouldn't affect its financial results in 2005. ®

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