Additionally, cryptographer Bruce Schneier, John Hopkins University cryptography professor Matthew Green and 67 others added their names below a post by Zeynep Tufekci, an assistant professor at the University of North Carolina's School of Information and Library Science, asking for the Guardian story to be retracted.
The original report said: "Facebook-owned WhatsApp, which has about one billion users, has not made it widely known that there is an aspect of WhatsApp that results in some messages being re-encrypted and resent automatically, without first giving the sender an opportunity to verify the recipient.
But on Wednesday, The Guardian's Paul Chadwick wrote: "The Guardian was wrong to report in January that the popular messaging service WhatsApp had a security flaw so serious that it was a huge threat to freedom of speech."
However he added, "But it was right to bring to wide public notice an aspect of WhatsApp that had the potential to make some messages vulnerable to being read by an unintended recipient.
"In a detailed review I found that misinterpretations, mistakes and misunderstandings happened at several stages of the reporting and editing process. Cumulatively they produced an article that overstated its case.
"The Guardian ought to have responded more effectively to the strong criticism the article generated from well-credentialled experts in the arcane field of developing and adapting end-to-end encryption for a large-scale messaging service."