Hi Dimi,
Sorry to bother you. By installing the latest version of tpm2-tools, encrypted communication is possible.
Seal/unseal was possible as shown below.
But I have one question. How can I detect if a MITM attack occurs during the seal/unseal process? After establishing a session, is there any way to get the EK certificate of that session?
It seems that the tpm2_getekcertificate command can only get certificates created via the createek command. I'd like to know if the TPM I've made a session with is genuine.
Seal:
> tpm2_createprimary -c prim.ctx
> tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
> tpm2_create -Q -g sha256 -u seal.pub -r seal.priv -i temp.key -C prim.ctx -S sess.ctx
> tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n
seal.name -c sealctx
> tpm2_evictcontrol -C o -c seal.ctx 0x81010001
> tpm2_flushcontext sess.ctx
Unseal:
> tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
> tpm2_unseal -c seal.ctx -S sess.ctx -o out.key
> tpm2_flushcontext sess.ctx
Thanks & Regards,
Joseph
------ Original Message ------
보낸 날짜: 2021-08-02 오전 6:27:36
제목: [tpm2] Re: Is the tpm2_create command safe against sniffing attacks?
Hi Dimi,
Thank you for your kind answer. Looking at the link you gave, I think I can get more ideas.
I've been trying session encryption via tpm2-tools all weekend.
But I haven't found a way to create an encrypted session in tpm2-tools yet. Maybe tpm2-tools doesn't support encrypted sessions?
If this is clear, I will implement parameter encryption through tpm2-tools with referring to wolfTPM
Thanks & Regards,
Joseph
------ Original Message ------
보낸 날짜: 2021-08-02 오전 4:33:02
제목: [tpm2] Re: Is the tpm2_create command safe against sniffing attacks?
Hi Joseph,
TPM 2.0 offers Parameter Encryption capability and HMAC sessions as measures against Man-in-the-middle attacks
Examples in wolfTPM demonstrate how to enable Parameter Encryption
There is also Keygen , Key import and Key loading examples with Parameter Encryption
If Parameter Encryption and HMAC session have been used, this story would have developed differently.
Hope this helps.
Dimi
--
Founder of TPM.dev
Hello,
In this article, can see that communication with the TPM is vulnerable to sniffing if not careful.
Is the disk encryption described in tpm2-software's blog safe against these attacks?
tpm2_createprimary -Q -C o -c prim.ctx
dd if=/dev/urandom bs=1 count=32 status=none | tpm2_create -Q -g sha256 -u seal.pub
-r seal.priv -i- -C prim.ctx
tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c seal.ctx
tpm2_evictcontrol -C o -c seal.ctx 0x81010001
My question is:
1. Is there a tool in linux that can sniff communication with the current system's TPM?
2. How to encrypt communications if the methods described above are not secure?
It seems that encryption is possible through tpm2_startauthsession , but I do not know how to apply it to tpm2_create . (The -S option simply did not work.)
Thank you.


_______________________________________________