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Security related stuff.

Practical


Theory


Unsorted


This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


TPM

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

What?

Trusted Platform Module is part of the Trusted Computing design.

The TPM is basically the hardware part, which helps give an isolated environment, to store some keys in and to do certain crypto in.


It being a separate thing

makes attack surface much smaller and some attacks much harder to do remotely,
makes it harder to steal keys,
meaning it doesn't have to expose the keys being used - they don't have to be in RAM while in use or on disk while not
Keys for some uses can be marked as "never move these out". Some other uses require them to be migratable, though.
lets you tie certain keys to the specific TPM
which alleviates certain physical attacks. For example, you can force an encrypted drive to only work on only one computer
you can prevent booting something that wasn't previously approved
as protection against malware that alters the boot (this )
note that secure boot only covers boot, only as much has the OS integrates with it, and stops there - it does nothing to to protect you against malware once booted.


Physically, TPM is often a hardware module that can be plugged into PC motherboards and laptops, and may be built into laptops (fairly common in business laptops). One can also be part of a CPU.

(You could also implement it in code, but doing so means you lose the trusted environment and the isolated storage which defeats half the point)



"Can't detect TPM device"

Means the BIOS knows that you can plug in a TPM module, and is looking for it (being told to, or always does), and doesn't find one.

So tell it not to look for one (if you can), plug one in, or ignore this message. It's often under a header named something like 'Trusted Computing'

Some BIOSes will always look for it(verify), in which case you can just ignore the message.

More acronyms

What does TPM not protect?

Use and criticism, strengths and weaknesses

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

See also

Nonce

Challenge/response

JSON Web Signature, Encryption, Tokens

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

JSON Web Signature (JWS)

Signing arbitrary data.

See also:


JSON Web Encryption (JWE)

Syntax for the exchange of encrypted data, and sending it in Base64 within JSON.

See also:


JSON Web Tokens (JWT)

JWT is aimed at sending verifiable claims, building on JWS or JWE

Signed using a shared secret, or a public/private key.

Typically used between identity provider and a service provider, in an SSO-like way.

See also:


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