NXP Semiconductors
AN13500
EdgeLock A5000 Secure Authenticator for electronic anti-counterfeit protection using device-to-device
authentication
Figure 23. Content of the reference private keys
Instead of a real private ECC device key the reference key contains mainly the
A5000 private key object ID. The remaining bytes are containing a 64-bit "magic
number" (always
0xA5A6B5B6A5A6B5B6
). The Plug & Trust Middleware documentation
provides a detailed description of the reference key format.
The NXP OpenSSL engine uses this "magic number" to distinguish a reference key from
a real private key. In case a reference key is passed to the OpenSSL API or command-
line tool the NXP OpenSSL engine will invoke the A5000 to perform the private crypto
operation.
4.6 Chain of trust of the pre-provisioned device certificates
A certificate is a digital document that contains a public key and additional information
about the entity associated with it. A certificate also includes a digital signature from the
certificate issuer. In case of the pre-provisioned A5000 certificates the certification issuer
is NXP. The image below shows the complete certification chain of the pre-provisioned
device certificates.
AN13500
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Application note
Rev. 1.0 — 28 March 2022
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