# Tag Info

9

In summary: the premise "there is so little space in the bootloader that no cryptographically secure decryption algorithm can be implemented there" is likely wrong; thus security-by-obscurity is not the way to go. The method described in the question attempts to "prevent theft from the publicly released update"; but it fails to do that if an adversary ...

7

No, it's not safe to seed a PRNG with the hash of a password, then generate a key from that PRNG. That is especially bad with DSA and shared parameters $(p,q,g)$, and only slightly less unsafe for RSA, or DSA with per-key parameters $(p,q,g)$. Two essentials things are missing: some slow step, and salt. If the proposed procedure was applied, all there is to ...

4

A cryptographic PRNG doesn't care what you feed it as entropy, as long as you provide enough. Furthermore, the PRNG will not reveal anything about its internal state, including what was fed to it as entropy. So in this sense it's safe to use a password as entropy: the PRNG will not expose it. The problem with a password is that compared with normal keys, it ...

3

It's usually not safe to initialize it with a password, because of the risk of brute-force attacks. Do a search and you'll find lots of warnings about this risk. Your proposed password generation method does not say anything about how long the password is or how you will choose it. If it's a 8-character password, no, it won't be secure. If it's a random ...

2

You need a large random prime modulus where the discrete log is hard. Read about how to choose a prime so the discrete log is hard. Also, you want $p-1$ to have as few small factors as possible. Therefore, the short version is, I suggest you choose a large random 2048-bit prime $p$ such that $(p-1)/2$ is prime. However, Pohlig-Hellman has some serious ...

2

A quick glance at their most recent paper shows some security analysis. Secton 2 talks about some different threats, what guarantees they can provide, etc. Section 8.3 also evaluates the security of the system. This may or may not be what you are looking for, you'd have to decide for your self.

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