% tpm2_verifysignature(1) tpm2-tools | General Commands Manual

NAME

tpm2_verifysignature(1) - Validates a signature using the TPM.

SYNOPSIS

tpm2_verifysignature [OPTIONS]

DESCRIPTION

tpm2_verifysignature(1) - Uses loaded keys to validate a signature on a message with the message digest passed to the TPM. If the signature check succeeds, then the TPM will produce a TPMT_TK_VERIFIED. Otherwise, the TPM shall return TPM_RC_SIGNATURE. If object references an asymmetric key, only the public portion of the key needs to be loaded. If object references a symmetric key, both the public and private portions need to be loaded.

OPTIONS

  • -c, --key-context=OBJECT:

    Context object for the key context used for the operation. Either a file or a handle number. See section "Context Object Format".

  • -g, --hash-algorithm=ALGORITHM:

    The hash algorithm used to digest the message. Algorithms should follow the "formatting standards", see section "Algorithm Specifiers". Also, see section "Supported Hash Algorithms" for a list of supported hash algorithms.

  • -m, --message=FILE:

    The message file, containing the content to be digested.

  • -d, --digest=FILE:

    The input hash file, containing the hash of the message. If this option is selected, then the message (-m) and algorithm (-g) options do not need to be specified.

  • -s, --signature=FILE:

    The input signature file of the signature to be validated.

  • -f, --scheme=SCHEME:

    The signing scheme that was used to sign the message. This option should only be specified if the signature comes in from a non tss standard, like openssl. See "Signature format specifiers" for more details. The tss format contains the signature metadata required to understand it's signature scheme.

    Signing schemes should follow the "formatting standards", see section "Algorithm Specifiers".

  • --format=SCHEME:

    Deprecated. Same as --scheme.

  • -t, --ticket=FILE:

    The ticket file to record the validation structure.

References

context object format details the methods for specifying OBJECT.

algorithm specifiers details the options for specifying cryptographic algorithms ALGORITHM.

common options collection of common options that provide information many users may expect.

common tcti options collection of options used to configure the various known TCTI modules.

signature format specifiers

EXAMPLES

Sign and verify with the TPM using the endorsement hierarchy

tpm2_createprimary -C e -c primary.ctx

tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx

tpm2_load -C primary.ctx -u rsa.pub -r rsa.priv -c rsa.ctx

echo "my message > message.dat

tpm2_sign -c rsa.ctx -g sha256 -m message.dat -s sig.rssa

tpm2_verifysignature -c rsa.ctx -g sha256 -m message.dat -s sig.rssa

Sign with openssl and verify with the TPM

# Generate an ECC key
openssl ecparam -name prime256v1 -genkey -noout -out private.ecc.pem

openssl ec -in private.ecc.pem -out public.ecc.pem -pubout

# Generate a hash to sign (OSSL needs the hash of the message)
echo "data to sign" > data.in.raw

sha256sum data.in.raw | awk '{ print "000000 " $1 }' | \
xxd -r -c 32 > data.in.digest

# Load the private key for signing
tpm2_loadexternal -Q -G ecc -r private.ecc.pem -c key.ctx

# Sign in the TPM and verify with OSSL
tpm2_sign -Q -c key.ctx -g sha256 -d data.in.digest -f plain -s data.out.signed

openssl dgst -verify public.ecc.pem -keyform pem -sha256 \
-signature data.out.signed data.in.raw

# Sign with openssl and verify with TPM
openssl dgst -sha256 -sign private.ecc.pem -out data.out.signed data.in.raw

tpm2_verifysignature -Q -c key.ctx -g sha256 -m data.in.raw -f ecdsa \
-s data.out.signed

returns

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