2
votes
0answers
8 views

Which cipher text is easiest to guess the plaintext?

I know that there are approximately 2^88 diff erent 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....
1
vote
1answer
19 views

Doubts regarding implementing AES128 bit algorithm in my IOT system

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 ...
0
votes
1answer
25 views

Capital passphrases with rainbow tables?

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 ...
-2
votes
0answers
17 views

How to implement this encryption related code in JavaScript? [migrated]

I have following code in Java. ...
-1
votes
2answers
40 views

Practical perfect security in bitwise XOR vs integer addition/subtraction cipher

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 ...
1
vote
1answer
22 views

Cryptographically secure hash function vulnerable to length extension attacks both to front and to back?

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?
0
votes
1answer
41 views

Time complexity of Weil pairing

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 ...
0
votes
0answers
22 views

ECDH: create Public Key from x, y coordinates [on hold]

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. ...
-1
votes
0answers
18 views

How to Securely Transmit Salt and IV vector

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 ...
2
votes
0answers
35 views

How many qbits are required to break Diffie-Hellman over a multiplicative group

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 "...
2
votes
0answers
25 views

Multilinear trapdoor commitments secure against concurrent man-in-the-middle attacks

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 ...
0
votes
0answers
17 views

How does CBC ESSIV disk encryption handle IV reuse?

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?
1
vote
0answers
21 views

Example of an attack on a message exchange which uses the homomorphic property

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.
-2
votes
0answers
31 views

encrypt data without a key, length stays the same, result differs each time? [on hold]

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 ...
3
votes
2answers
100 views

Could a 6502 CPU safely compute a SHA-1 hash in a reasonable length of time?

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 ...
-4
votes
1answer
47 views

Triple Data Encryption Standard

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?
1
vote
2answers
33 views

How to provide partial confidentiality and full integrity for a protocol message?

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 ...
0
votes
0answers
28 views

ECDSA signature uniqueness

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 ...
0
votes
1answer
17 views

Can I use PKCS#5 with CBC? [duplicate]

As far as I know there are two padding mechanisms, which are PKCS 5 and 7. Which one should be used for CBC?
1
vote
1answer
32 views

How do i manage encryption keys with a cloud provider?

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 ...
0
votes
0answers
31 views

Can anyone explain the mathematics behind Elliptic curve Signature generation and verification(ECDSA)? [on hold]

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 ...
1
vote
1answer
32 views

Eliptic curve verifiable secret sharing

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} (...
-4
votes
0answers
21 views

can somone decypher this? [on hold]

it's rc4 and the base is Base64 it's important JcKCw7vCqCwbNjTCpMK3YxrDkMOAK8O0w7jDskolPcKtSMKhwow9AULCpMOVw5jDjEPCijsFwqNaw4rCisOnYzN1NnjDsTrDrsORAjIzwrrCkE/...
2
votes
2answers
52 views

How does linear vs. non-linear operations relate to cryptographic security and differential cryptanalysis?

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 ...
1
vote
0answers
41 views

What should I change in my implementation to pass from a curve $y^2=x^3+1$ to $y^2=x^3+x$

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 ...
2
votes
0answers
31 views

Where to find parameters for particular supersingular curve

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 + ...
3
votes
3answers
493 views

When do I need to use CBC and HMAC?

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 ...
2
votes
1answer
43 views

How long random value is required in random masking method?

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 ...
2
votes
0answers
27 views

Key update and re-keying

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 ...
-1
votes
2answers
59 views

is it possible to get key in One time pad

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?
1
vote
0answers
36 views

Suggestion for proof of retrievability (via coding theory)

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 ...
-1
votes
0answers
54 views

Need help decrypting, very complex [on hold]

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 ...
3
votes
1answer
112 views

What form of ECC can we use to make sure our newly invented ECC based crypto-systems are quantum secure?

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? ...
4
votes
1answer
87 views

Synthetic Jitter to Combat Timing Attacks

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?
1
vote
1answer
30 views

Trivial Broadcast Encryption Scheme for video conferencing how well does it handle users joining or leaving a call?

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 ...
1
vote
0answers
78 views

On Linux, seeding /dev/urandom does not unblock /dev/random, causing libsodium to hang?

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, ...
2
votes
0answers
18 views

Is it possible to successfully encrypt/decrypt in DUKPT using different sized BDKs?

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) ...
0
votes
0answers
4 views

Hadoop Transparent Data Encryption: protection from interference of EDEK, EZK and DEK [migrated]

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 ...
0
votes
2answers
35 views

Good Diffie Hellman Encryption Method

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 ...
2
votes
2answers
67 views

Encryption using static AES256 symmetric key vs ephemeral session key

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 ...
0
votes
1answer
69 views

Avoid decrypting every password in a password manager

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, ...
0
votes
0answers
45 views

Showing that a cipher is not a perfect cipher

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 ...
1
vote
0answers
33 views

Is timing attack practical in a web developer's perspective?

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 ...
2
votes
2answers
94 views

How to use Homomorphic encryption for secure computing Arctan() function?

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 ...
-1
votes
0answers
21 views

Which Approach is Better in Pseudorandomness - Asymptotic or Concrete? [on hold]

When to prefer these 2 approaches over each other and which one is more secure.
4
votes
1answer
132 views

Identifying the type of algorithm for a PRNG that uses modular multiplication and addition

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 ...
1
vote
1answer
73 views

Hashing based on the discrete logarithm problem

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, $H(x)$ ...
0
votes
1answer
42 views

SHA's finite character set and collision

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 ...
2
votes
1answer
126 views

AES with linear S-Box

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?
0
votes
0answers
29 views

Key Agreement, one end Bouncy Castle, the other end OpenSSL/TomLibCrypt [on hold]

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 ...

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