Microsoft is not using SHA-1 for signing of CRLs or end entity certificates. However, we are currently using SHA-1 to sign some OCSP responses and will stop using it by 2022-06-01.
On Friday, January 21, 2022 at 11:54:49 AM UTC-8 [email protected] wrote: > All, > > This email launches a new discussion related to sunsetting the future use > of SHA1 in the Mozilla Root Store Policy (MRSP) > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/>. > > > > It is related to GitHub Issue #178 > <https://github.com/mozilla/pkipolicy/issues/178> (as well as Issue #201 > <https://github.com/mozilla/pkipolicy/issues/201>). > > SHA1 is still allowed to be used in signing SMIME certificates, Authority > Revocation Lists (ARLs), and CRLs, and OCSP responses (but see CABF Ballot > > <https://lists.cabforum.org/pipermail/servercert-wg/2022-January/003090.html> > > SC53: Sunset for SHA-1 OCSP Signing > <https://lists.cabforum.org/pipermail/servercert-wg/2022-January/003090.html> > ). > Can the future use of SHA1 signing be eliminated from the MRSP altogether, > and if so, on what timeframes? > > Currently, SHA1 is mentioned in the MRSP as follows: > ----------- > *Section 5.1.1 RSA* > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/#511-rsa> > > When a root or intermediate certificate's RSA key is used to produce a > signature, only the following algorithms may be used, and with the > following encoding requirements: > > - > > RSASSA-PKCS1-v1_5 with SHA-1. > > The encoded AlgorithmIdentifier MUST match the following hex-encoded > bytes: 300d06092a864886f70d0101050500. > > See section 5.1.3 for further restrictions on the use of SHA-1. > > Section 5.1.3 SHA-1 > <https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/#513-sha-1> > > > CAs MAY sign SHA-1 hashes over end-entity certificates which chain up to > roots in Mozilla's program only if all the following are true: > > 1. > > The end-entity certificate: > - is not within the scope of the Baseline Requirements; > - contains an EKU extension which does not contain either of the > id-kp-serverAuth or anyExtendedKeyUsage key purposes; > - has at least 64 bits of entropy from a CSPRNG in the serial > number. > 2. > > The issuing certificate: > - contains an EKU extension which does not contain either of the > id-kp-serverAuth or anyExtendedKeyUsage key purposes; > - has a pathlen:0 constraint. > > Point 2 does not apply if the certificate is an OCSP signing certificate > manually issued directly from a root. > > CAs MAY sign SHA-1 hashes over intermediate certificates which chain up to > roots in Mozilla's program only if the certificate to be signed is a > duplicate of an existing SHA-1 intermediate certificate with the only > changes being all of: > > - a new key (of the same size); > - a new serial number (of the same length); > - the addition of an EKU and/or a pathlen constraint to meet the > requirements outlined above. > > CAs MAY sign SHA-1 hashes over OCSP responses only if the signing > certificate contains an EKU extension which contains only the > id-kp-ocspSigning EKU. > > CAs MAY sign SHA-1 hashes over CRLs for roots and intermediates only if > they have issued SHA-1 certificates. > > CAs MUST NOT sign SHA-1 hashes over other data, including CT > pre-certificates. > > ----------- > > I am thinking that we could amend MSRP sections 5.1.1 and 5.1.3 to have > sunset dates and to also say something to the effect that: > > "CAs MUST NOT sign SHA-1 hashes over any data." > > Thoughts? > > Thanks, > > Ben > > > > > > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/mozilla.org/d/msgid/dev-security-policy/62346f69-b34b-49c3-b977-d4134712f481n%40mozilla.org.
