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tpm2 — the command API

github.com/go-tpm2/tpm2 is the transport-agnostic, pure-Go TPM 2.0 command API. It sits one layer above common: common owns the big-endian wire codec and the Transport contract, and this package turns that codec into typed TPM 2.0 commands — from Startup / GetRandom / PCR ops up through full measured-boot attestation. v0.6.0.

go get github.com/go-tpm2/tpm2

A TPM wraps any common.Transport — a *crb.CRB, a *tis.TIS, an *efitcg2 caller, or a *devtpm.Transport:

tpm := tpm2.New(transport) // transport implements common.Transport

if err := tpm.Startup(uint16(common.SUClear)); err != nil { /* ... */ }

rnd, err := tpm.GetRandom(20)

sel := []tpm2.PCRSelection{{Hash: uint16(common.AlgSHA256), PCRs: []int{0, 7}}}
_, digests, err := tpm.PCRRead(sel)
err = tpm.PCRExtend(0, uint16(common.AlgSHA256), eventDigest)

What it ships — the full attestation chain

Attestation (Quote + off-TPM verify)

ak, akPub, _ := tpm.CreatePrimary()                  // ECDSA-P256 AK
quoted, sig, _ := tpm.Quote(ak, nonce, sel)          // TPM2_Quote
info, err := tpm2.VerifyQuote(akPub, quoted, sig, expectedPCRs) // off-TPM

VerifyQuote checks the ECDSA-P256 signature and re-derives and compares the pcrDigest.

Seal a secret to PCR state (measured-boot payoff)

parent, _ := tpm.CreateStoragePrimary()
priv, pub, _, _ := tpm.SealToPCR(parent, secret, sel, pcrValues)
// …later, unseals ONLY if the PCRs still hold pcrValues:
got, err := tpm.UnsealWithPCR(parent, priv, pub, sel, nonceCaller)

Credential activation (attestation identity)

ek, ekPub, _ := tpm.CreateEK()                        // EK Credential Profile
res, _ := tpm2.MakeCredential(ekPub, akName, secret, rand.Reader) // off-TPM
recovered, err := tpm.ActivateCredential(ak, ek, session,
    res.CredentialBlob, res.Secret)                   // TPM2_ActivateCredential

MakeCredential + TPM2_ActivateCredential prove the AK and the EK live on the same TPM — the binding a verifier needs before it will trust a quote.

Import / WrapToPCR

Wrap an external secret (off-TPM) to a node's storage key + a PCR policy so the node imports + unseals it only when its boot PCRs match — control-plane secret sealing for attested nodes.

Other groups

  • NV storage — NVDefineSpace / NVWrite / NVRead / NVReadPublic / NVUndefineSpace.
  • GetCapability — typed decoders: GetPCRBanks, GetTPMProperties, GetManufacturer, GetAlgorithms, GetHandles.
  • Foundation — Startup, GetRandom, SelfTest, PCR_Read / PCR_Extend.

Each method marshals its parameters with common.BuildCommand (the right TPM_ST tag + TPM_CC), calls Transport.Send, and parses with common's codec. Every flow above is proven against a real swtpm by validate.

Conventions

Pure Go, CGO_ENABLED=0, big-endian TPM wire (via common), GOWORK=off, BSD-3-Clause on every file, 100% statement coverage.