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tpm2-software / tpm2-tools

The source repository for the Trusted Platform Module (TPM2.0) tools
https://tpm2-software.github.io
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tpm2_hmac not working with symmetric key #3423

Open bharath1294 opened 2 months ago

bharath1294 commented 2 months ago

I am trying to load AES256 key and want to calculate dgst using sha1.

Commands used: openssl rand -out aes-128.key 16 openssl rand -out challenge.bin 16 tpm2_loadexternal -G aes128 -r aes-128.key -c key_handle name: 000bb3847c63c273860a2ea7da767bec90db8b339e90ee28391cb30533ecbb05b084 tpm2_hmac -c key_handle -g sha1 -o response.bin challenge.bin WARNING:esys:src/tss2-esys/api/Esys_HMAC.c:300:Esys_HMAC_Finish() Received TPM Error ERROR:esys:src/tss2-esys/api/Esys_HMAC.c:100:Esys_HMAC() Esys Finish ErrorCode (0x000002d2) ERROR: Esys_HMAC(0x2D2) - tpm:parameter(2):unsupported or incompatible scheme ERROR: Unable to run tpm2_hmac

JuergenReppSIT commented 2 months ago

At https://github.com/tpm2-software/tpm2-tools/issues/1597#issuecomment-889882601 you will find how to import a symmetric key for HMAC computation. If you need sha1 you have to use -G hmac:sha1 for the import command.

bharath1294 commented 1 month ago

Hi @JuergenReppSIT Thanks for responding, however i have one more issue. I want to calculate using sha1 and the comment you mentioned defaults to sha256 eventhough i change the parameter. Can you share how to enable the command to use sha1

Command: tpm2_import -C primary.ctx -G hmac -gsha1 -i aes-128.key -u aes-128.pub -r aes-128.priv

name-alg: value: sha1 raw: 0x4 attributes: value: userwithauth|sign raw: 0x40040 type: value: keyedhash raw: 0x8 algorithm: value: hmac raw: 0x5 hash-alg: value: sha256 raw: 0xb

JuergenReppSIT commented 1 month ago

you should use: tpm2_import -C primary.ctx -G hmac:sha1 -gsha1 -i aes-128.key -u aes-128.pub -r aes-128.priv `