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    SubjectRe: [PATCH v6 06/14] x86: Add early SHA support for Secure Launch early measurements
    On Tue, May 09, 2023 at 06:21:44PM -0700, Eric Biggers wrote:

    > SHA-1 is insecure. Why are you still using SHA-1? Don't TPMs support SHA-2
    > now?

    TXT is supported on some TPM 1.2 systems as well. TPM 2 systems are also
    at the whim of the firmware in terms of whether the SHA-2 banks are
    enabled. But even if the SHA-2 banks are enabled, if you suddenly stop
    extending the SHA-1 banks, a malicious actor can later turn up and
    extend whatever they want into them and present a SHA-1-only
    attestation. Ideally whatever is handling that attestation should know
    whether or not to expect an attestation with SHA-2, but the easiest way
    to maintain security is to always extend all banks.


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