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compact rsa private key format

As shown in Why does my SSH private key still work after changing some bytes in the file? a typical RSA private key file contains. The public modulus $n$ and exponent $e$; The private ...
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Encryption used in a commercial software product [closed]

I found (through some reverse-engineering) that the following encryption scheme is used in a commercial software that is quite widely used in Germany (Security by obscurity at its best). I have the ...
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Why is AES-SIV not used, but AESKW, AKW1?

I'm trying to investigate different key wrapping algorithms for my implementation. I've noticed that AES-SIV is very rarely implemented by most of open source libraries. Most of them implements key ...
36 views

Elliptic ElGamal Public Key Cryptosystem doubt

I need an example of Elliptic ElGamal Public Key Cryptosystem. I have been trying with some values but I don't get the right solution. I have $p=13$, the elliptic curve $E:y^2=x^3+11x+7$ and a point ...
341 views

Need for salt with IV

I have mainly referred to this question http://stackoverflow.com/questions/1949640/does-iv-work-like-salt . Definitely in case of using a salt, IV has a use of adding randomisation to each and every ...
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Proven secure scheme under random oracle

Currently I am trying to understand random oracle model in order to make a small presentation about it but I seem to be very confused about it. Since it's an hypothetical model without a real life ...
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How to test an implementation of a homomorphic scheme?

I want to implement the following homomorphic encryption scheme from On-the-Fly Multiparty Computation on the Cloud via Multikey Fully Homomorphic Encryption by Lopez-Alt et al. I use C++ and I want ...
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Proof that a hash matches an encrypted file

Assume that Alice has a file $F$ which she is going to send, in encrypted form to Bob. Alice possesses $F$ and an encryption key $K$. She sends to Bob the encryption of $F$ using $K$, $E(F,K)$ as ...
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Protocol to identify zone of potential agreement without revealing reservation prices and having to trust third parties?

A wants to buy a company from B. Before A and B enter negotiations, they want to make sure that there actually is a zone of potential agreement. Obviously, they don't want to communicate their ...
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Which crytographic standard were RC5, CAST5 and Blowfish based on? [closed]

Which crytographic standard were RC5, CAST5 and Blowfish based on? A. AES B. RC2 C. 3DES D. DES
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Known plaintext, ciphertext, encryption method (AES CBC) and IV (static) [duplicate]

I know the plaintext, the ciphertext, the encryption method (AES CBC) and the IV -- which is static. While not able to perform a chosen plaintext attack per se, I can obtain many known ...
2k views

Hash function that allows to decide if A > B if you only have hash(A) and hash(B)?

Is it possible to construct a hash function with the following property? If you have hash(A) and hash(B) with A and B being integers, you can tell if A is greater than B -- without however knowing ...
49 views

Proof that perfect privacy implies that the number of keys is at least the number of messages

I was reading a proof to the statement: Perfect privacy implies that $|K| = |M|$ where I am pretty sure that $K$ is the set of keys and $M$ is the set of messages. The proof is the following, ...
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Finding differentials and space complexity

Most of article about differential cryptanalysis present the generic method, the way to find sub keys. But I can't find a clear explanation about how to find the differentials used in examples. In ...
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Is IPsec IND-CCA secure provided the used block cipher is a pseudorandom function?

I am trying to solve the question whether "IPsec is IND-CCA secure provided the used block cipher is a pseudorandom function" (with IPsec using a variant of Encrypt-then-MAC) As a resource I am given ...
53 views

Why Generate Keys are inside game

I am studying reductions to prove security of crypto systems. Generally are used "games" for the proves. For example, the next image is extracted from the page 91 of the book Postquantum Cryptography. ...
56 views

Convert messages to elliptic curve points [duplicate]

Let $E$ be an elliptic curve; $\alpha,\beta$ two points of $E$; and $a$ a private key such that $\beta=a\cdot\alpha$. We choose random integer $k$ and plain text $x\in E$. Encryption and decryption ...
Alice holds a secret $a \in X$. Bob holds a secret $b \in X$. Is there a protocol that lets them compute $f(a, b) = \begin{cases} 1 & \textrm{if } a = b \\ 0 & \textrm{else} \end{cases}$ If ...
Effect of $L_n[1/4,c]$ integer factorization on RSA-2048
Using the L-notation, integer factorization of an integer $n$ has the best known complexity of $L_n[1/3,c]$ using general number field sieve. Would discovery of an algorithm with complexity ...