# All Questions

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### Generation of strong primes

It seems that this is pretty difficult to find large (above 1024 bits) strong primes, or at least such primes p where (p-1) has a very large prime factor. Is there any information regarding the ...
160 views

### Schnorr Identification protocol sometimes wrong?

I'm implementing the Schnorr Identification protocol as part of a larger protocol. In a large percentage of cases, around 20%, my test fails. I don't think it's a code problem, although possible, but ...
24 views

### transforming RC2 keys to have effective minimum length in implementations with fixed effective lengths

mcrypt's implementation of RC2 has a fixed effective length of 1024 bits, however, it is possible to simulate keys with effective lengths between 1-1024 by doing something like this: ...
26 views

### Encrypt algorithm [duplicate]

Is it possible to encrypt an algorithm? What I mean by this is have a remote/cloud computer execute a program that will process some data... And the remote computer would not be able to know anything ...
35 views

### block cipher algorithms with variable block lengths

Rijndael supports block lengths of 128, 192 and 256. AES does not but Rijndael does. What other algorithms support variable block lengths? Or is Rijndael unique in that regard?
32 views

### A rudimentary challenge–response authentication based on dot products in $\mathrm{GF}(2)^k$

We are building a rudimentary challenge–response authentication protocol based on dot products in $\mathrm{GF}(2)^k$. Assume a user has a password $\mathbf{p} \in \mathrm{GF}(2)^k$. When logging in, ...
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37 views

### Diceware word list for six dice

I really like Diceware, but it now needs six words to be safe. Instead of adding a word, I would think that increasing the size of the wordlist and adding an extra dice would be a better idea. I have ...
35 views

### CoAP authentication using DTLS

what is the meaning of this notation ?? AES{Yi, (Yi XOR Ki | nonce1)} https://tools.ietf.org/html/draft-bhattacharyya-core-coap-lite-auth-00
78 views

### Elliptical curve cryptography key generation time

I am currently trying to learn more about Elliptical curve crypthography and have finally started to get things working and undestanding the different pieces. I've written a small project in C# and ...
68 views

### Sharing an encrypted file between a group of people

Is there any way to share an encrypted file with a group? In the other words, can I encrypt a file with a public key so that each person in a group decrypt it with his/her private key? Is there any ...
59 views

### Bilinear Map vs Inner Product [migrated]

What is the difference between a Bilinear Map and a Inner Product?
62 views

### Gap problem for Learning With Errors

Informally, a "Gap" problem is the one that arises when solving the computational (or search) version using an oracle for the decisional version. For example, the Gap Diffie-Hellman Problem (GDH) is ...
158 views

### When would one prefer a proof of knowledge instead of a zero-knowledge proof?

I've just realized I find it hard to distinguish between these two terms (proof of knowledge, and zero-knowledge proof), specially where only the latter seems to be used in many cryptographic ...
80 views

### Cracking plain RSA by factoring the modulus n

This is the setup: I have both public and private keys of one "instance" of RSA. And I have only the public key of another RSA cryptosystem, but this system has the same modulus as the first one. I ...
21 views

### Wiring pattern for field multiplier

I am doing a project to implement point multiplication unit in elliptic curve cryptography. Going for a galois field multiplier in normal basis. The point multiplication unit is for higher field size ...