# All Questions

26 views

### Parallel authentication of encrypted data. What AE type to choose?

I've got a system with a slow data transfer channel. Transferring a message through several channels does increase the transfer speed significatnly. AES-CBC+HMAC is good except that verifying the MAC ...
48 views

### Generating random numbers from thread timing in C++

Do these codes generate true random numbers? If not: can you prove their pseudo-randomness? For computers with more than two CPUs ...
22 views

### Meaning of pseudocode “$(C, S):=$”

I've seen pseudocode of this form in the Montgomery Multiplication related theses: $(C, S) := a[j]*b[0]+C$. What's the meaning of "$(C, S):=$", or what is the real code that converted from this ...
22 views

### Does anyone still use BAN or GNY logic in practice?

I want to implement a simple protocol, and I'd like to verify it through BAN or GNY logic. I would assume that if these logics are still used that there would be some programs available that would ...
44 views

### Reasons for components of AES

I started reading "Cryptography: theory and practice" by Stinson, and I am trying to understand the reason behind the choices for the different components of AES since they seem quite arbitrary. In ...
40 views

### Working on subgroup of $\mathbb{Z}^*_p$ in practice

It is said that, given a group $\mathbb{Z}^*_p$, we can always have a subgroup whose order is prime. To this end, for a safe prime $p=2q+1$, compute $x_i^2 \bmod p$ for all $x_i \in \mathbb{Z}^*_p$. ...
55 views

### Is there any practical attack to create a printable chosen prefix MD5 collision?

I would like to create two ASCII text messages with the same MD5. Is this possible? If not, is there a similar but less strict attack that could work? Or to rephrase my last question: what are the ...
38 views

### Easy explanation of “IND-” security notions?

There are many schemes that can advertise themselves with certain security notions, usually IND-CPA or IND-CCA2, for example plain ElGamal has IND-CPA security but doesn't provide IND-CCA security. ...
31 views

### Does XTS provide random write access?

I'm trying to find a sufficient encryption mode that supports random read and write access. It seems like XTS is a perfect fit, since in my use case authentication and integrity insurance are handled ...
31 views

### Using password-based encryption as a hashing scheme

Classic scheme: Given password and hashing algorithm Generate salt Calculate ...
50 views

26 views

### TLS encryption with a self-signed PKI and Python’s asyncio module

I want to enable TLS encryption with a custom / self-signed PKI for a self-contained distributed system built with Python 3’s asyncio. I’ve read Python’s ssl docs as well as several tutorials: ...
21 views

### How to multiply two field elements generated by bilinear paring map? [on hold]

I wish to clarify how to multiply two field elements generated by bilinear paring map. The following is an example where I need to multiply e1 and e2. is it possible? If yes, then how? FieldElement ...
62 views

If I have an original file and a WinRAR password protected .rar file containing that file, than can I extract the password?
28 views

### Forgery attack on OCB

When using same nonce in OCB mode of authenticated encryption, how forgery attack can be done?
32 views

### Establish authentication

I have designed a basic authentication scheme where two nodes will mutually authenticate that other holds a shared secret. I have very limited RAM/ROM (its on uC) and bandwidth. Here it goes: ...
45 views

### HMAC-SHA1( secret key ) with header of a transmitted file

Given: an AES-128 secret key (ASecKey) encrypts a file (CBC mode). (Assume good random) Is is insecure to append (include) an HMAC-SHA1 of ASecKey to file? Purpose: The receiver can then quickly ...