Cisco Systems Yahoo are combining their technologies to combat email spam and forgery, the AP reports. Announced Wednesday, the new technology combines techniques that rely on cryptography to help determine whether the sender of an email message is legitimate. The combined technology, DomainKeys Identified Mail, borrows elements from Yahoo's Domainkeys and Cisco's Internet Identified Mail system; both attach scrambled digital signatures to mail, which then can be checked to ensure that it was actually sent from the domain in the sender's address. Both Yahoo and Google have deployed Domainkeys. Others, including Microsoft, have proposed other anti-spam technologies. Eventually, such a system is expected to become part of the internet email standard.