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TAGPMA SHA-2 Migration Timeline

[Updated Nov 8 2013.]

October 2012:

  • CA certificates in the IGTF distribution and CRLs at official distribution points should use SHA-1.
  • CAs should issue SHA-1 end entity certificates on request.
  • CAs may issue SHA-2 (SHA-256 or SHA-512) end entity certificates on request.
  • CAs may publish SHA-2 (SHA-256 or SHA-512) CRLs at alternate distribution point URLs.
December 1 2013:
  • CAs should begin to phase out issuance of SHA-1 end entity certificates.
  • CAs should issue SHA-2 (SHA-256 or SHA-512) end entity certificates by default.
April 1 2014:
  • New CA certificates should use SHA-2 (SHA-256 or SHA-512).
  • Existing intermediate CA certificates should be re-issued using SHA-2 (SHA-256 or SHA-512).
  • Existing root CA certificates may continue to use SHA-1.
December 1 2014:
  • CAs may begin to publish SHA-2 (SHA-256 or SHA-512) CRLs at their official distribution points.
December 1 2014:
  • All issued SHA-1 end entity certificates should be expired or revoked.

In case of new SHA-1 vulnerabilities, the above schedule may be revised.


EUGridPMA Recommendation (September 2012)

The recommendation is that CAs will not issue general availability SHA-2 certs before 1 August 2013 [RP datum point] If SHA-1 is broken, revocation and transition will be immediate as inspired by the categorization in the HASHRAT document (seconds to few months). The scheduled end of life for SHA-1 EECs is 1 September 2014, meaning that SHA-1 EECs SHOULD have a validUntil date no later than that date. If there are CAs with EECs having a later date, the primary mitigation of the risk in case SHA-1 is broken will be removal of said CA from the IGTF distribution. CAs SHOULD have SHA-2 issuing capability by October 1st 2012 No need to move any existing CA self-signed root certs to SHA-2 if we rely only on the distributed metadata. Since intermediate CAs are distributed but the distribution may be superseded by dynamic CA chains (subject to the namespace constraints) ... SHOULD be SHA-2 after 31 March 2014, and if SHA-1 it MUST be revoked and re-issued if and when SHA-1 is broken (like for EECs). Once broken, the new intermediates will be distributed or both the intermediates and root removed from the distribution. New CA certs generated after April 2014 SHOULD be SHA-512 from, noting that existing (self-signed) CA certs MAY be SHA-1

Only SHA-256 and SHA-512, and not 224 nor 384. Each CA MAY pick its own variant. CRLs on the default CDP SHOULD be SHA-1 until at least 1 September 2014. CAs MAY start distributing SHA-2 based CRLs after that date, and MAY have SHA-2 based CRLs available on alternate CDPs after 1 October 2012. If same subject is signed twice (once SHA-1 once SHA-2) must use different cert serial numbers. Same is true of CRLs with same data. Must be different sequence number. Breakage of the SHA-1 algorithm in a way that allows trivial generation of plaintexts with a specific hash necessitates removal of SHA-1 algo support. This is a software vulnerability issue outside of our scope and SHOULD be dealt with using regular vulnerability mechanisms of the RPs. It then WILL necessitate SHA-2 based root certs as well. The 'end-of-life' SHA-2 migration recommendation does not apply to certificates with a short life time (for SLCS CAs) until at least 1 September 2014.

This recommendation does not address attribute authorities OCSP will continue to use SHA-1

TAGPMA concerns with above EUGridPMA recommendation

  • "CAs SHOULD have SHA-2 issuing capability by October 1st 2012" but some TAGPMA CAs don't have this capability yet.
  • Do not accept threat of removal of CAs from the IGTF distribution "in case SHA-1 is broken".
  • Do not accept a prohibition on issuing SHA-2 certificates before 1 August 2013.
  • CAs that issue 13 month certificates do not accept the recommendation that we must switch to SHA-2 on exactly 1 August 2013 given the 1 September 2014 date. Requiring us all to switch on a single day is too restrictive.
  • OSG requests transition period extended to 1 October 2014.

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