All Questions

I know that there are approximately 2^88 different permutations of 26 characters. The stream cipher A5/1, which generates a binary keystream using three irregularly clocked LFSR, and has a 64-bit key....

I want to implement AES128 in my IOT network which consists of a Master device which runs Linux on it and slave devices which are 8-bit microcontrollers that periodically transmit data packets to the ...

I'm currently trying to learn how rainbow tables work for a personal project of mine, but I am a little bit confused on how passphrases can be found. Here are the steps that seem do this, from the ...

I have following code in Java. ...

XOR already provides perfect security in theory but it's hard to apply it in practice due to strict requirements. I was thinking about whether simple addition/subtraction in integer format would not ...

Is there any hash function where both $\text{hash}(m\|k)$ and $\text{hash}(k\|m)$ are vulnerable to length extension, but $\text{hash}(m)$ is itself secure?

I ran and timed an implementation of the Weil pairing on three set of parameters. One with an order of 512 bits, one with 256 bits and the last with 161 bits. I took the Miller's algorithm to compute ...

I have the x, y coordinates of a EC public key ( i have the bytes also ). I need to convert the x,y coordinates bytes into a ECPublicKey. ...

Hello I wanted to ask something about my scheme. As we know, salt is being used to prevent rainbow attacks. In my scheme, in order to let the receiver to decrypt some data,generated one time to be ...

There have been comparisons between RSA and ECDH with regards to the number of qbits (qubits) required to break the algorithm with a specific key size. But how many qbits are required to break "...

I am trying to understand how to apply a multi-trapdoor commitments described by Gennaro and what makes them secure against a concurrent MiM attack. There are two ways to construct a multi-trapdoor ...

From what I've read, ESSIV deterministically generates an IV from the encryption key and the sector number. When I change a sector on the drive, and it gets encrypted, how does it handle IV reuse?

Can someone give me an example of an attack on a message exchange using this encryption scheme, that uses the homomorphic property? Note: It is not a homework question.

I am attempting to solve my friends encryption algorithm, however I have yet to even believe such a thing is possible: Rules: the cipher must result in the same length, the encryption process does ...

The 6502 is the CPU in a Tamagotchi (which can be hacked to run custom code). SHA-1 is the default hash used for TOTP (the algorithm used by two-factor authentication tokens and apps). Hopefully you ...

Based on this, it looks like something slightly wrong. What would need to be adjusted at the transmitter side to allow the receiver to decrypt the message/data?

I want to provide confidentiality and integrity for a protocol. I don't want to encrypt the entire protocol message. I do not want to encrypt the header and timestamp of the protocol message, but I ...

I've been trying to replicate an ECDSA signing process that a cryptosystem uses (EOS, in this case), and I've been having issues. Namely, testing my c++ code (which uses openSSL) and comparing the ...

As far as I know there are two padding mechanisms, which are PKCS 5 and 7. Which one should be used for CBC?

I would like to provision services from a Software as a Service (SaaS) provider. This is multitenant environment (multiple companies will be using a single instance of the application, with a single ...

I know that there are two components r and s in a signature but I am trying to understand what are these values in terms of elliptic curve co-ordinates, the curve equation and also modular arithmetic ...

I am implementing the following the algorithm instructions as shown in 1 (section IV, B). When trying to verify the share given the commits, $a_jG$ verifier $i$ checks whether $f(i)G=\sum_{j=0}^{t} (...

it's rc4 and the base is Base64 it's important JcKCw7vCqCwbNjTCpMK3YxrDkMOAK8O0w7jDskolPcKtSMKhwow9AULCpMOVw5jDjEPCijsFwqNaw4rCisOnYzN1NnjDsTrDrsORAjIzwrrCkE/...

I understand what a linear operation is and what a non-linear operation is, but I would like an explanation of specifically how a non-linear operation on input data mitigates differential crytanalysis ...

I tried to change my implementation of pairing in curves $y^2 = x^3 + 1$ to use curves of the type $y^2 = x^3 + x$ but it didn't work. I thought the only thing I had to change in my code was the ...

In the PBC (Pairing Based Crypto) library, the curve parameters of the type A pairings are constructed on the curve $y = x^3 + x$ of embedding degree $2$. I implemented a code for curves $y^2 = x^3 + ...

As I know CBC does not provide integrity for the message, thus HMAC is used to provide integrity for CBC message. Also, I hear about CBC-MAC which can provide integrity and confidentiality. Which one ...

I heard that random masking method requires a random number whose length is as long as a message to be sent, but I’m not sure that. So, I'd like to ask about that. 1. Boolean masking : $ x_i \oplus ...

What is the exact difference between the key update and re-keying? Following the discussions here, I understood that the key update is the process of deriving the new session key from old key. In the ...

In one time pad cipherText1 xor cipherText2 == plainText1 xor plainText2 so is it possible to find out key by 2 cipherText and plainText's xor?

I want to build a fully open-source open-everything protocol/service for massively-distributed shared storage (P2P). I came up with a suggestion for a proof-of-retrievability scheme, but I would like ...

So I received a message from a friend that said "21 E5 B2 C6 04 90 C8 51 E0 5C 2D B4 3C 47 B9 0D AB E3 FF B6 5E 88 45 8B" and I was told it has 4 layers of encryption. The first is to convert ...

It seems a lot of crypto-systems that are based on elliptic curves are susceptible to quantum computing attacks. Hence, what forms of ECC cryptosystems are quantum secure, and how can we prove that? ...

We are working on some tooling. It has a networking kernel. We would like to think that jitter built into the kernel would help with timing attacks? Is this true?

Consider the trivial Broadcast Encryption Scheme for video conferencing, where each user shares a long-lived key with the broadcaster, and the session key used to encrypt a multicast message (or ...

Edit for clarity: Does the "standard" test for initialization of the Linux non-blocking entropy pool, by attempting to read 1 byte from /dev/random, ignore seeding of /dev/urandom from file at boot, ...

We are having our P2PE Solution validated against the PCI P2PE standard. We currently use a TDEA 2-key based BDK, and IPEK in both the encryption and decryption environments. ANSI X9.24-1 (2009) ...

I am preparing a response to a security auditor. They have presented a generic question about the protection from substitution of KEK and DEK in a "normal" encryption mechanism. What protection ...

I've just made my own implementation of Diffie Hellman in nodejs (its for a project of mine). However the shared keys are integers, I want to use those integers as a key to encrypt data. This is an ...

For a hackathon I am designing an information exchange system for healthcare. Healthcare data is stored on unsecured systems. I want to assure confidentiality, integrity and authenticity of this data ...

The Setup I'm making a password manager for fun. It stores a random encryption key, encrypted with a key derived from the master password, and then it stores the data, which is a list of (site, ...

I was given this problem: Prove that the following ciphers are not perfect, using as few blocks as you can. There is no need to prove that the number of blocks is indeed minimal. DES AES-128 AES-256 ...

Let's say my server has a non-constant-time compare function for checking if the visitor has a valid session id. The time it takes for the comparator to run would be very insignificant, usually within ...

In the multi-party communication(MPC), if partyA has the coordinate(x1 y1) and partyB has the coordiante(x2,y2), how two parties can securely compute Arctan((y1-y2)/(x1-x2)) without revealing their ...

When to prefer these 2 approaches over each other and which one is more secure.

GNU libc uses the following pseudo-random number generator: $$(\mathit{state} \times 1,103,515,245) + 12,345 \pmod {2^{31}}$$ where state is the result of the previous call to the generator. My ...

At a first look, one could use the elliptic curve discrete logarithm problem to grant for the onewayness of $H(x)=x*G$ (where $G$ is the generator point of the cyclic subgroup). Additionally, $H(x)$ ...

From what I've researched, SHA's hex encoded string contains the characters [a-fA-F0-9]. If we represent it in Base64, it can contain ...

If the AES S-Box is replaced with a linear or affine transformation, for instance the identity mapping $\sigma(x)=x$, does the cipher become entirely affine and hence trivially weak?

I am struggling like mad, I have an existing system using tomlibcrypt to verify a key agreement, and when running key agreement in openSSL the two agree byte for byte on the shared key. However when ...