All Questions

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Berlekamp-Massey algorithm, correct stepping

I'm trying to use the Berlekamp-Massey algorithm on the following bit sequence: 0 1 0 0 1 0 0 1 0 1 I have the correct answer and most of the approach to get there, but I'm unable to fill in what I ...
1k views

encryption and decryption time for RSA-crt in java? [duplicate]

I try compute execution time for encrypt and decrypt data has 1024 bit = 128 byte in RSA-crt algorithm. I need this results. But I believe this result wrong. because big diffrent between execution ...
218 views

Advantages to knowing $p$ and $q$ in Blum Blum Shub?

Do you gain any advantage by knowing the factorization of $M$ (over just knowing $M$ itself) in the Blum Blum Shub generator? The only advantage I see is being able to calculate the $i$-th number ...
172 views

Is it possible to find data which makes sense when decrypted with different keys?

In theory, does a piece of data exist which, when encrypted (using any method) with a given key, makes some sense when decrypted with the wrong key? Here, a definition of "some sense" might be ...
660 views

How random is the shared secret in the Diffie Hellman key agreement

How random is the value $ZZ$ in the DH protocol? This question was triggered by this somewhat naïve implementation in I2P shown by Sergei at Stackoverflow. Obviously $ZZ$ is distinguishable from a ...
129 views

Ed25519 with R replaced by H(RAM)?

Ed25519 signatures consist of $(R, s)$, where $s = r + H(RAM)a$ $mod$ $l$, and $R = rB$. This differs from the Schnorr signature where instead of $R$, the signature contains the hash $h=H(RAM)$. ...
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Is it necessary to generate a private key for each encryption process?

I read about Asymmetric key cryptography like EG-ECC , RSA, ECDH. I understand the concept of mathematics to these algorithms. But I have wondered about the public key for sender and private key for ...
1k views

Is AES key length a size of the key or entropy?

While educating my self I'm having hard time to understand what an 128 bit AES key actually means? Is it a key length or entropy? Please explain to me trough following example (assuming AES): ...
115 views

In Pedersen Key Distribution, can the public key be persistent?

I am implementing a key distribution protocol described by Torben Pedersen in A Threshold Cryptosystem without a Trusted Party (EUROCRYPT'91). In the protocol, the $n$ parties distribute a public key ...
2k views

Problems with using AES Key as IV in CBC-Mode

I'm a pentester and currently analysing a web application which are using some strange encryption scheme. The point is: They encrypt using AES-128, generate a (not cryptographic secure) key and use ...
144 views

Generating unsigned, bounded random value using signed bounded random values

Use case: I have a random number generator that can generate random numbers in a range that is limited by a number $x$, say $x$ ranges from $2$ to $2^{(n - 1)} - 1$ exclusive. In this case $n$ is $16$,...
2k views

ECDSA vs RSA: Performance on Android platform and surprising results

For our privacy-preserving protocol, an encrypted channel is established. In order to protect our system from man-in-the-middle attacks, signature-based approach is used. After we've implemented it ...