Miffed certificate authorities are calling on Google to give websites more time to upgrade the security used in browser-to-server communications before displaying warnings in Chrome.
The CAs are upset over Google's roughly six-month timetable for ratcheting up the notices that begin this month for Chrome users visiting sites that do not upgrade from SHA-1 to SHA-2.
SHA, which stands for "secure hash algorithm," is used in scrambling data moving on a secured connection between a browser and a web server. Browsers typically display an HTTPS in the URL when such a connection exists.
Most websites use a SHA-1-based signature as part of their certificate chain. The hash algorithm has well-known security weaknesses that go away with SHA-2.
However, switching from SHA-1 to the newer version involves updating all public key certificates (PKCs) issued by a CA. Because many organizations have dozens or even hundreds of certificates, such an upgrade requires time to change affected systems and then test them for possible problems, Wayne Thayer, general manager of security products at CA issuer GoDaddy, said.
"Google doesn't really understand how much pain this is both for large enterprises and for small mom-and-pops," Thayer, who is also a member of the CA Security Council's steering committee, said.
Google declined comment. However, in a Sept. 5 blog post, the company said it wanted to pressure websites to make the change before there is a successful attack in which hackers intercept sensitive data, such as credit card numbers or personal information.
"We need to ensure that by the time an attack against SHA-1 is demonstrated publicly, the Web has already moved away from it," the company said.
While Google believes it's doing the right thing, CAs disagree that the threat warrants such an aggressive timetable. Instead, they prefer Microsoft's approach of waiting until Jan. 1, 2017, before phasing out support for SHA-1 in Internet Explorer.
"If there was clear evidence that SHA-1 could be defeated as a hashing algorithm, we would the first one to say, 'Hey, you need to replace these immediately,'" Rob Hoblit, senior director of product management for Symantec, said. "There doesn't need to be a rush to upgrade for something that still works and is going to be disruptive for a lot of customers."
Besides providing too little time, CAs say Google should not start placing notices in URLs during the Christmas shopping season, particularly since e-commerce sites won't have the time to perform such a dramatic upgrade during the busiest time of the year.
"A lot of our customers, particularly those that are doing e-commerce, go into full lockdown mode for their infrastructures in November and December for the holiday shopping season," Hoblit said.
Google's SHA-1 plans start Sept. 26 with the release of Chrome version 39. Sites using certificates that expire after Dec. 31, 2016, and that utilize SHA-1 will be treated as "secure, but with minor errors."
That means Google will start displaying a yellow triangle over the lock image next to the HTTPS.
With the release of Chrome 40 Nov. 7, sites using SHA-1 certificates that expire between June 1, 2016, and Dec. 31, 2016, will be treated as "neutral, lacking security."
Such sites will still get the HTTPS in their URL, but there will no longer be a lock next to it.
Starting with Chrome 41, set for release in the first quarter of 2015, sites using SHA-1 certificates that expire after Dec. 31, 2016, will be treated as "affirmatively insecure" and get a red X over the lock image and a red strike-through over the HTTPS.
In addition, people visiting such a site will be warned of potential security problems and will have to click through the warning to access the site, according to Thayer.