3 ms·

One thing that seems to be missing from your project is the actual "HSM-ness". Things like side channels and so probably are not relevant to the target market,

by dfox 10y ago

One thing that seems to be missing from your project is the actual "HSM-ness". Things like side channels and so probably are not relevant to the target market, but some kind of assurance that device's firmware was not tampered with is probably required.

btchip 10y ago
Well side channel attacks should be very relevant for all projects involving security. And several similar projects have already been produced (see TREZOR, KeepKey in the Bitcoin space), based on a similar chip which is in my opinon not great for that kind of use case (the fuse protection mechanism is not certified, the chip doesn't offer any protection against active physical attacks and so on) - that's well explained in the original Yubico article.
- lisper 10y ago
  The SC4-HSM is not designed to be secure against physical compromise, but it can be made resistant against such attacks by encrypting the keys with a pass-phrase. This is not a perfect solution because the pass-phrase needs to be entered through a non-secure host, but it's better than nothing. An attacker would need to compromise the pass phrase and obtain physical possession in order to mount a successful attack.
  - btchip 10y ago
    the projects I quoted above have the same "security model" then
  - dfox 10y ago
    With this security model it is in essence no better than plain USB flash drive. I would assume that adding at least some protection against physical attacks could be reasonably simple and would greatly expand the usefulness of the device (eg. making it somehow inherently tamper-evident and replacing the DFU bootloader with something custom and open that does the same thing as RDP Level 1, but without the bricking risk)
    - lisper 10y ago
      > With this security model it is in essence no better than plain USB flash drive I disagree. With the right firmware, the SC4-HSM can securely generate keys that cannot be compromised without decapping the chip.
- lisper 10y ago
  > the original Yubico article Which article are you referring to here?
lisper 10y ago
The "HSM-ness" comes from the fact that there's a hardware RNG that can be used to generate keys. Firmware assurance comes from the fact that it's user-flashable.

by dfox 10y ago

btchip 10y ago

Well side channel attacks should be very relevant for all projects involving security. And several similar projects have already been produced (see TREZOR, KeepKey in the Bitcoin space), based on a similar chip which is in my opinon not great for that kind of use case (the fuse protection mechanism is not certified, the chip doesn't offer any protection against active physical attacks and so on) - that's well explained in the original Yubico article.

lisper 10y ago
The SC4-HSM is not designed to be secure against physical compromise, but it can be made resistant against such attacks by encrypting the keys with a pass-phrase. This is not a perfect solution because the pass-phrase needs to be entered through a non-secure host, but it's better than nothing. An attacker would need to compromise the pass phrase and obtain physical possession in order to mount a successful attack.
- btchip 10y ago
  the projects I quoted above have the same "security model" then
- dfox 10y ago
  With this security model it is in essence no better than plain USB flash drive. I would assume that adding at least some protection against physical attacks could be reasonably simple and would greatly expand the usefulness of the device (eg. making it somehow inherently tamper-evident and replacing the DFU bootloader with something custom and open that does the same thing as RDP Level 1, but without the bricking risk)
  - lisper 10y ago
    > With this security model it is in essence no better than plain USB flash drive I disagree. With the right firmware, the SC4-HSM can securely generate keys that cannot be compromised without decapping the chip.
lisper 10y ago
> the original Yubico article Which article are you referring to here?

lisper 10y ago

The "HSM-ness" comes from the fact that there's a hardware RNG that can be used to generate keys. Firmware assurance comes from the fact that it's user-flashable.