# All Questions

81 views

### Why does 3DES need private key to decrypt?

I create two files, my.cer and my.pem ( include certificate and private key), I encrypt a file with my.cer, I use openssl smime -encrypt command. When decrypting data, it needs my.pem. I think 3DES ...
71 views
+100

### culling equivalent Enigma keys for short messages

The following for-loop iterates over all possible keys for an M3 Enigma for three selected rotors: ...
171 views

### Encryption-then-encode or encode-then-encryption?

I have this question in which I m struggling. I have read in many sites about encrypt-then-mac etc. If the confidentiality for transmission is needed, discuss the feature for the order of encryption ...
59 views

### What would currently make the strongest https connection?

when you look at the encryption websites use you will see that there is alot of diversity, some use 256 bit keys some do not, some use DHE-RSA some ECDHE some use sha 256 some sha1, but my question is,...
57 views

### Does encryption of data/information take place in peer to peer networks like Gnutella, Bittorrent?

Do peer to peer networks like Gnutella, Bittorrent have any encryption system to secure the users privacy or encrypt the file/data being shared? Elaborate please.
58 views

### bruteforce on aes 256 cbc mode

i have a series of encrypted text , they encrypted by aes 256 bit cbc mode for every encrypted text there is an iv that i have them also and i know its algorithm is aes 256 bit cbc mode i can ...
52 views

### Is PKCS7 a signature format or a certificate format?

I always though PKCS7 was a signature format. However, on the net I find several references to PKCS7 being a certificate format - for example, this talks about PKCS7 certificate: Extract raw ...
55 views

### Output of a Linear Shift Register given Plaintext and intial state

Given an initial state $S_0 = (0101)$ and plaintext $P = 1010101011$ I need to find the ciphertext. The method to solve this was not taught in my coursework, and the information I have found online ...
28 views

### Some terms related to secret sharing: Optimality, What does it mean?

In any secret sharing scheme we have to develop step by step. After constructing such scheme we need to reduce share size. Why? e.g. Robust secret sharing scheme is modified Shamir secret sharing ...
37 views

### Is the ring learning with errors problem still hard if the errors are drawn from some subspace?

Let $R=\mathbb{Z}_p[x]/x^n+1$ be the ring used in normal RLWE, which is linear space over $\mathbb{Z}_p$ with dimension of $n$, let $S$ be a linear subspace of $R$ which described by linear ...
56 views

### Name of an archaic type of RSA padding (0BBBBBBB…)

In some legacy code, I encountered RSA signature padding in the following format (hexadecimal): 0B BB BB BB BB BB BB ... BB BB <hash> Is there a name for ...
64 views

### Why is Diffie-Hellman used instead of just RSA in key-exchange (TLS, IKE)?

Why should a key exchange protocol (such as in TLS or IKE) use Diffie Hellman? Why not just use RSA? For example: Alice picks a random session key, signs it, encrypts it with Bob's public key, and ...
43 views

### How can I obtain the raw decimal value of an RSA key's modulus?

So maybe I'm thinking about this too hard, or maybe I'm missing a piece of information. We'll use Google for this example. Say I wanted to obtain the modulus of Google's current public key. Well I ...
626 views

Next to the traditional MD5 and SHA-1, other hashing algorithms exist based on symmetric encryption algorithms. An example is the Matyas–Meyer–Oseas construction. What are the advantages/...
41 views

### Why is synthetic IV (SIV) mode considered deterministic authenticated encryption (DAE)?

I was just going over my (old) notes from Coursera's Cryptography I course, and I was puzzled by the description of SIV as providing deterministic authenticated encryption (DAE). The general SIV ...
56 views

### identifying presence of encryption of zero in additive homomorphic encryption

Lets say the server has corpus of ciphertext contains $enc(a),enc(b),enc(c), \dotsc enc(x)$. The encryption function is an additive homomorphic scheme (like Paillier). The server knows only the public ...
81 views

### Calculating Polynomial Inverse with extended euclid in java

I'm trying to understand the NTRU-PKCS and therefor I wanted to code a naive Version of it. Now my Problem: I tried to calculate the inverse of a Polynomial with an extended Version of euclids ...
67 views

### Using Pollard's lambda in a key-recovery attack on DH

I've become interested in writing an exploit for the OpenSSL vulnerability here (CVE-2016-0701). Running through the bullets describing the attack, I can follow up to the last bullet point. Reviewing ...