analysing cryptographic algorithms, potentially uncovering weaknesses in them (e.g. "breaking" them or casting doubts on their actual security)
1
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1answer
167 views
Other than brute force, are there any attacks on Threefish-512 using only a single known plaintext block?
As per title, other than brute force, are there any attacks on Threefish-512 using only a single plaintext block? Are there any attacks like this in any other cipher?
1
vote
1answer
447 views
Verilog simulation of Data Encryption Standard
I interested in developing DES(in verilog) for my college project.Can i get help in understanding the simulation results of DES encryption and decryption ?
thanks in advance .
1
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0answers
101 views
Security of stream cipher based on Matrix multiplication GF(256) with randomized padding
The actual question is stated at the end of the text. Suppose you have a (grossly inefficient) confidentiality stream cipher with the following components:
The keyed function ...
1
vote
0answers
175 views
Deciphering a Message [closed]
I have this message to decipher:
UYDVKUYEHJNRFRLYZIPVSUQYGAFFBXKAJLVRIETJIUOTSVKXHQZUWYLIOQHQEJR
I have tried using methods such as:
Ceaser cipher, Atbash cipher, Railfence etc.
I also tried ...
1
vote
0answers
76 views
Two untrusted party want to exchange data: how to ensure each one gets the data it needs? [duplicate]
Possible Duplicate:
Two untrusted party want to exchange data: how to insure each one gets the data it needs?
I am trying to come up with what could maybe be a novel algorithm for an ...
0
votes
1answer
156 views
What is the probability of breaking the AES algorithm?
I am doing a project which requires the encryption to be done using AES. Is it really possible (technically) to crack AES?
If yes, please tell me:
What is the probability of breaking AES?
How ...
0
votes
2answers
132 views
CPA distinguisher for matrix multiplication in GF(256) with randomized padding
What is the best CPA distinguisher for the function $F_k:\{0,1\}^{8n}\to\{0,1\}^{16n}$ described below?
Let $E_k$ be a $2n\times2n$ matrix with elements in $GF(2^8)$, selected by generating bit ...
0
votes
1answer
125 views
Possibility of factorisation of rsa modulus due to vulnerability in java implementation code
Below is my implementation of the RSA algorithm. Actually I'm choosing the private key (d) instead of public key (e) and computing the public key.It is working fine but
I want to know if this is a ...
0
votes
2answers
118 views
Breaking RSA, given a special kind of oracle that decrypts related ciphertexts for us
Let $c=E^{RSA}_{e}(w)$ be the ciphertext belonging to the plaintext $w$ if an $RSA$ system is used. Assume that the public exponent $e$ satisfies $e \le 10$. Furthermore, assume there is an oracle ...
0
votes
1answer
86 views
decryption many time pad
I have eleven ciphertexts that were encrypted with the same key (which I don't know). I want to decrypt the last ciphertext. I read similar question like Many time pad attack but I can't solve my ...
0
votes
1answer
51 views
Efficient algorithm for remainder calculation over prime field for ECC implementation?
I am working on 224-bit elliptic curve cryptography. In this 224-bit * 224-bit multiplication results 448-bit output. I am reducing 448-bit into prime field range( prime number $2^{224}-2^{96}+1$) ...
0
votes
1answer
104 views
How to solve the reverse of an equation that uses MOD?
I've been tasked with reverse engineering an unknown crypto function. The function uses the following constants:
$a=380951$:
I noticed that this is a prime number
$b=3182$:
I noted that this is a ...
0
votes
1answer
169 views
Break double encryption
Let $E_k$ : {0,1}$^l$ be a block cipher encryption function with block-size $l$ and key-length $n$.
In class, we saw that a double encryption with two independent keys $E{}'_{k_1k_2}(x)$ = ...
0
votes
2answers
223 views
Cryptanalysis of S-DES - Equations
I am trying to derive equations for s and t in the cryptanalysis of a Simple DES algorithm, but I haven't been able to deduce it. I've attached an image of the portion that I'm referring to, and I'd ...
0
votes
1answer
313 views
Cryptanalysing Affine cipher
I am trying to cryptanalyse a cipher–text encrypted by Affine cipher.
The encryption formula is: $c = f(x) = (ax+b)\bmod m$, where $a$ and $b$ are unknown constants; $x$ is a plain-text symbol, and ...
0
votes
1answer
317 views
How to hack the new save encryption on ipad for uplink? [closed]
The new iPad version of Uplink appears to be using some new saving mechanic than the PC/Mac Version. Macs and PCs use 'RedShirt' but the iPad appears to instead be using 'SAV62' at the start of saves, ...
0
votes
1answer
110 views
amateur cryptosystem -> a very long boolean expression -> attempt to reduce it [closed]
(newbie here) I try to analyze amateur cryptosystem and wondering, if it's possible to reduce it as reduce a very long boolean expression? What tool can I try to use?
0
votes
0answers
54 views
Strength of Combining Hash functions [duplicate]
If I combine two hash functions, what will the impact on the strength of the resulting function.
If I combine in following way:
H1*H2 (multiply)
H1 + H2 (concat)
H1 Xor H2
H1 (H2)
EDIT:
Lets say H1 ...
0
votes
0answers
47 views
How compute encrypt and decrypt runtime for agorithm [closed]
I programming RSA algorithm is the following two function in java language in my thesis
...
0
votes
0answers
46 views
How compared encryption algorithm in terms of efficiency
I doing to compare two algorithm cryptography. first algorithm is RSA cryptography and second algorithm is El Gamal elliptic curve cryptography. now I want a way to compare between two algorithm by ...
0
votes
0answers
75 views
Actual weakness RSA [closed]
I need modern trends analysis RSA. Hinek books "Cryptanalys RSA and Yan "Cryptanalytic RSA" have been read. What else?
0
votes
0answers
80 views
How to encrypt OpenVPN setup traffic [closed]
I have an OpenVPN server and a client that can successfully connect to said server. The traffic over the tunnel is encrypted. The tunnel works quite well.
However what is NOT encrypted (cleartext) is ...
0
votes
0answers
64 views
Need help with student project about IT security [closed]
I've been studying in university for computer security for 4 years.
All students have to make a course project by the end of year. And I have some problems with it.
I need help with the project's ...
0
votes
0answers
46 views
Elliptic curve Cryptography [duplicate]
Possible Duplicate:
Can we use elliptic curve cryptography in wireless sensors?
How to map message character to point lies on Elliptic Curve? how to ecc used in wireless sensor networks? ...
0
votes
0answers
109 views
What will be the way to go about deciphering this kind of cipher? [closed]
I've come across this cipher and have tried unsuccesfully to decipher it.
http://codepad.org/aea7Wuyl
The only 'hint' that I have gotten so far as to how I am supposed to crack it is the word ...
-1
votes
1answer
177 views
detecting ROT13/base64 encryption
Is there anyway to detect that a cipher is encrypted with ROT13 Or Base64 without decrypting it using the algorithm and check that the result means (works)?
I mean does an algorithm exists that test ...
-1
votes
1answer
81 views
What is the complexity of the Square attack against the reduced 4-rounds 128-bit Rijndael variant?
I'm looking at a square attack against a reduced version of AES-128 with only 4 rounds (with block and key size of each 128 bit). I have a set of 256 plaintext-ciphertext block pairs.
What is the ...
-1
votes
0answers
58 views
Tools to assist learning cryptography in real world [closed]
Hey I am new to cryptography and I wanna see how cryptography works in the real world. Suggest me some tools which will help get me a better idea about cryptography. (If it were networking I would ...
-1
votes
1answer
100 views
Chosen Plaintext Attacks
Assuming the ability to launch Chosen Plaintext Attacks (CPA), how many oracle calls an attacker
needs to break the affine cipher? and how
-1
votes
2answers
165 views
Cryptographic Symmetric Stream Cipher
Let me know a cryptographic symmetric stream cipher system with only two functions say S() and P() and it should satisfy the following conditions:
There will be two independent computers say M1 and ...
-2
votes
1answer
90 views
ASCII Message in TV show? [closed]
So I was watching a popular series tonight (Person Of Interest) when suddenly during a frame change I noticed a very quick blue screen with writing.
At the time I never thought anything of it as it ...
-2
votes
1answer
320 views
Is a steganographic technique which has a universal decoder novel/secure? [closed]
I've come up with an approach to steganography which needs review of both its cryptography and its math. There's a complete working implementation at https://github.com/bramcohen/DissidentX and the ...
-4
votes
1answer
213 views
-4
votes
1answer
250 views
finding collision for truncated SHA1 hash output
Suppose we truncate only 40 bits of sha1 hash output.hence it is insecure.how can we find two message as input which gives first 40 bits of hash as same value i.e we have to find collision for first ...
-4
votes
2answers
145 views
Any techniques for evading frequency based crypt analysis without encrypting?
Are there any general techniques for evading frequency based crypt analysis without using any encrypting techniques
-5
votes
1answer
97 views
My Hand Cipher, Can some one tell if it secure [closed]
In easy steps how it works,
Convert txt to numbers . mod 1-26.
Generate random numbers (By my other cipher) equal to plain txt.
Write random numbers under txt numbers.
txt= LOI - txt number= 12 15 ...
