Microsoft has announced it will not support digital certificates issued by Chinese outfits WoSign and StartCom as “they failed to maintain the standards required by company’s Trusted Root Programme”.

“[Microsoft has] Observed unacceptable security practices including back-dating SHA-1 certificates, mis-issuances of certificates, accidental certificate revocation, duplicate certificate serial numbers and multiple CAB Forum Baseline Requirements (BR) violations,” the company said in a post on Wednesday.

The Microsoft Trusted Root Certificate Programme supports the distribution of qualifying root certificates in Microsoft Windows and other Microsoft products and services.

The decision means ace windows 10 will not trust any new certificates from these Chinese Certificate Authorities (CAs) after September 2017 and allow “natural deprecation of WoSign and StartCom certificates by setting a “NotBeforea date of 26 September 2017”, the company said in the post.

Google, Apple and Mozilla binned WoSign certificates in 2016.

Microsoft said it values the global Certificate Authority community and only makes these decisions after careful consideration as to what is best for the security of our users.

Meanwhile, WoSign has dubbed Microsoft’s post “misleading”.

According to a report in The Register, the company said it has replaced its root certificate in November and that its recent certificates present no risk to users.

StartCom claims to be “the 6th biggest CA in the world, securing more than half a million websites worldwide”.