2:05 AM
2

For those who don't know, a bijective function is one for which each input yields one and only one output. A block cipher, for example, is guaranteed to be bijective or you could not decrypt. When a hash function like SHA256 or SHA3 is used with an input the same length as its output, AFAIK this ...

3 hours later…
5:05 AM
Hello, I want to learn about developing apps with HSM using C/C++. I am looking for HSM emulator. any one knows about good one for learning purpose, I tried thales website cpl.thalesgroup.com/encryption/hardware-security-modules/… but I dont know how to get the app

3 hours later…
7:50 AM
1

Hi I know there have been other questions like this on here, namely here. But of all the solutions I have seen of this problem, $e_1$ and $e_2$ are relatively prime, which is how we can get to the final equation $m \equiv c_1^{\,a} \cdot c_2^{\,b} \pmod n$, where $a$ and $b$ are from the equa...

8 hours later…
4:04 PM
Hello everyone. I've been busy with academia so I haven't had time to give to cryptography. I have a question that was brought up by a student regarding en.wikipedia.org/wiki/Dual_EC_DRBG when I was talking about random numbers (16-bits in RFID so not cryptography related)
I am trying to find something for that Dual_EC_DRBG exploit that I could distill down to a sophomore class. Is there a Dual_EC_DRBG exploit for idiots presentation around somewhere? I'm the idiot in this case, but I hope to get to a point where I can drag them through it. Any advice would be appreciated.
I thought it'd be a fun "well, this something else" that's not RFID thing.
of course, after I ask this, I find the perfect thing

1 hour later…
5:17 PM
@bdegnan Like this one
5

From what I read, the backdoor in Dual_EC_DRBG operates by using related $P$ and $Q$ points. Did I understand the idea correctly? Dual_EC_DRBG works by multiplying the $P$ point with the seed initially, and then using the $x$-coordinate of the previous resulting point (let's call that $S$) inst...