Update Your SHA-1 Certs If You Haven't Already

"SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function designed by the United States National Security Agency and is a U.S. Federal Information Processing Standard published by the United States NIST and published in 1995...In 2005, cryptanalysts found attacks on SHA-1 suggesting that the algorithm might not be secure enough for ongoing use...Microsoft, Google, and Mozilla have all announced that their respective browsers will stop accepting SHA-1 SSL certificates by 2017." 1,2


I wanted to make you aware of some new research that indicates a practical exploit of SHA-1 will be possible in the next few months:


SHA-1 has been theoretically compromised for some time, but we believe this new information requires action.

If your unit has any active SHA-1 certificates in place, we would strongly recommend developing a plan to have them updated as soon as reasonably possible.

Please note that InCommon does not allow you to renew a SHA-1 certificate to a SHA-2 certificate -- they will need to be created as new certificates.

If you have any questions or concerns, you might refer to the following resource:


or feel free to let us know.

Thanks for your vigilance!



1  "SHA-1Wikipedia: The Free Encyclopedia. Wikimedia Foundation, Inc.

2  Microsoft has announced that it will end support not only for its browsers, but for its operating systems.

Written by CNS OIT staff
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