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Root certificate problem in the pipeline

Not particularly fresh news to some people but definitely important for anyone relying on SSL connections to websites who now need to plan for getting SSL certificates from a Root CA that uses SHA-2.

Microsoft Security Advisory 2880823

Deprecation of SHA-1 Hashing Algorithm for Microsoft Root Certificate Program

Published: November 12, 2013

Executive Summary

Microsoft is announcing a policy change to the Microsoft Root Certificate Program.
The new policy will no longer allow root certificate authorities to issue X.509 certificates using the SHA-1 hashing algorithm for the purposes of SSL and code signing after January 1, 2016.
Using the SHA-1 hashing algorithm in digital certificates could allow an attacker to spoof content, perform phishing attacks, or perform man-in-the-middle attacks.

Recommendation: Microsoft recommends that certificate authorities no longer sign newly generated certificates using the SHA-1 hashing algorithm and begin migrating to SHA-2.
Microsoft also recommends that customers replace their SHA-1 certificates with SHA-2 certificates at the earliest opportunity.


For example, here are the details from a current VeriSign certificate:



Will this impact any versions of Windows?

According to:


Windows PKI Blog

SHA2 and Windows

Published: September 30th, 2010


the support for SHA2 will vary:

No support for SHA2 – Windows XP sp2, Windows 2003 sp2

Limited support for SHA2 – Windows XP sp3 with KB 938397/KB 968730, Windows 2003 sp2 with KB 938397/KB 968730

Full support – Windows Vista and above

Note – “Limited support” added by the hotfixes mentioned includes the following SHA2 hashes: SHA-256, SHA-384, SHA-512 (but not SHA-224).


What’s up with SHA-224?

According to Alejandro Campos Magencio’s cryptography blog

Decrypt my World

SHA-2 support on Windows XP

Published January 23rd, 2009

Regarding SHA-224 support, SHA-224 offers less security than SHA-256 but takes the same amount of resources. Also SHA-224 is not generally used by protocols and applications.


Further reading

Security Research and Defence Blog

Security Advisory 2880823: Recommendation to discontinue use of SHA-1

Published November 12th, 2013

Print | posted on Friday, August 29, 2014 5:26 PM |


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