NIST FIPS 186-5 states that it is recommended that the security strength associated with the bit length of n and the security strength of the hash function be the same, or higher upon agreement. Given NIST P384 curve is used, force using either SHA384 or SHA512. Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@xxxxxxxxxxxxx> --- certs/Kconfig | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/certs/Kconfig b/certs/Kconfig index 1f109b0708..84582de66b 100644 --- a/certs/Kconfig +++ b/certs/Kconfig @@ -30,9 +30,11 @@ config MODULE_SIG_KEY_TYPE_RSA config MODULE_SIG_KEY_TYPE_ECDSA bool "ECDSA" select CRYPTO_ECDSA + depends on MODULE_SIG_SHA384 || MODULE_SIG_SHA512 help - Use an elliptic curve key (NIST P384) for module signing. Consider - using a strong hash like sha256 or sha384 for hashing modules. + Use an elliptic curve key (NIST P384) for module signing. Use + a strong hash of same or higher bit length, i.e. sha384 or + sha512 for hashing modules. Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem, when falling back to building Linux 5.14 and older kernels. -- 2.34.1
