# All Questions

16 views

### what is the key and IV size in CBC encryption and Decryption [on hold]

In my question what is the key size and key size must be fixed and what is the size of IV in CBC encryption and decryption. I already tried with out IV. But the key size and IV size don't know.
30 views

### Which hardware-accelerated AES-GCM implementations support encryption in-place? [on hold]

By encrypt in place I mean the following. Suppose I have an input plaintext of length L and I have also allocated an extra E bytes at the start and/or end of the buffer, with E << L. So the ...
24 views

### Key expiration policy for 3DES / TDES / Triple DES

I have a system that signs plain text messages using a message authentication code (MAC) encrypted with Triple DES. The short message is used on connection to establish a session key, so it would take ...
28 views

### Use same PGP key for private and business mail addresses [migrated]

I'm asking myself which one is better: Use the same PGP keypair for use with both private email addresses and business email addreses Use two seperate PGP keypairs, one for private and one for ...
53 views

### Authenticated encryption without padding

I want to encrypt data and protect its integrity and confidentiality. However, I cannot increase the length of the data. Are there any cipher modes of operation which provide confidentiality and ...
219 views

### How can I implement the elliptic curve MOV attack myself?

I understand and have implemented elliptic curve signatures in Python without the use of libraries like Sage, and would like to implement the MOV attack against certain weak types of elliptic curves. ...
1k views

### Zero Knowledge Password Proof

I'm working on implementing a cryptographic system and I'm trying to understand the Zero Knowledge Password Proof concept. So here's some background: To generate a secret key I am: Doing an ECDH ...
49 views

### Tweakable encryption algorithms vs Key wrapping

I have read many articles about Key wrapping and tweakable cipher modes. However, I don't understand the main difference between them? What you recommend for Key storage and Key Archive.
51 views

### Secure Broadcast Channel

I've read a paper that says that one of the "assumptions" that it makes is secure broadcast. Why is this an assumption? Can't a broadcast channel be built with simple primitives--i.e. encrypt and sign ...
177 views

### Hashing fundamentals

I have some ideas floating around my head for exploring hashing functions, but I want to make sure what I think I know is actually true, before basing a house of cards on it :) Let’s start with some ...
43 views

### SHA-256 Wrong registers

I have a problem with my sha256 java implementation. The registers (a…h) are correct until j=24; ...
122 views

### What key exchange protocols give Forward-Secrecy resisting future progress?

I (wrongly) understood what I've been told as meaning DHE in TLS, PFS in IPSec do not provide Forward-Secrecy; and I'm told that common forward-secure key exchange protocols are restricted to ...
15 views

### Random numbers for Master Key and Key_block

Exploration through RFCs concludes that random numbers used in the creation of Master Key and Key Block(Key material for Encryption Key and Mac Secret) are from ServerHello.random and ...
107 views

### Long-term data protection, storage of old encrypted traffic and quantum cryptocalipse

Tony Arcieri makes an interesting point in his Imperfect Forward Secrecy article which basically boils down to: large entities such as NSA are storing encrypted internet traffic, also what's to stop ...
70 views

### Unpredictability vs randomness

I'm experimenting with creating an entropy source for an environment where I have no hardware available and the language is very high level (executed in a virtual machine). I know it's not a good idea ...
90 views

### Why is “multiplying” $g^x$ and $g^y$ not possible?

The computational Diffie-Hellman problem states that for a cyclic group $G$ of order $p$ and a generator $g$, it is hard to find the value $g^{xy}$ given only $g^x$ and $g^y$ (but easy if either $x$ ...
34 views

### How to decrypt 3DES in ECB mode (using a wordlist)?

I have some encrypted texts (encrypted with 3DES in ECB mode without salt). My question: How can I decrypt them using a wordlist? (or without one) Example: Encrypted text: ...
For every set of twin primes $y,z$ let $n=8z^{2}y$ and ${e}=z^{3}+2yz$. Then I claim: $$\cfrac{4e}{n}=\cfrac{1}{2}+\cfrac{1}{y}+\cfrac{1}{z},$$ That this is true can be seen simplifying the ...