The growth comes as large e-mail providers and ISPs adopt e-mail authentication technology in an effort to help thwart spam and phishing attacks.
Though they differ in terms of technology and implementation, both SIDF and DKIM aim to authenticate e-mail by providing some form of verification for the domain from which a particular e-mail was sent.
A new study from IronPort Systems reports that 35 percent of all Internet e-mail is authenticated with SIDF, while 9 percent is authenticated with DKIM. In terms of enterprise adoption, 45 percent of all Fortune 100 firms use DKIM while 75 percent use SIDF.
Patrick Peterson, IronPort CTO, told internetnews.com that the majority of DKIM signers also publish SIDF records.
He noted that the overlap is probably about two out of every three which would yield a 38 percent to 40 percent number for the total of all e-mail authenticated by either method.
Over the last 12 months, overall adoption of e-mail authentication has increased by 60 percent. IronPort forecasts that adoption will grow by another 50 percent over the next 12 months.
IronPort's study is based on an analysis of traffic from its SenderBase traffic monitoring network, which it claims monitors over 25 percent of global Internet traffic.