# All Questions

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### Python. RSA common modulus attack problem

I have: N = /*500 decimal numbers*/ E1 = 3740453 E2 = 4226171 M^E1 = /*500 decimal numbers*/ M^E2 = /*500 decimal numbers*/ I must use RSA common modulus ...
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### Bilinear Map vs Inner Product

What is the difference between a Bilinear Map and a Inner Product?
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### Gap problem for Learning With Errors

Informally, a "Gap" problem is the one that arises when solving the computational (or search) version using an oracle for the decisional version. For example, the Gap Diffie-Hellman Problem (GDH) is ...
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### Can a secret message be securely transmitted within a MAC tag?

A sender wants to transmit an ultra secret code $M$ which could be either 'go', 'stop' or 'wait'. This could be any selection of code words really and adopted for any use such as transmitting short ...
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### java.util.Random and Dice Rolls

For this question, a dice roll will be considered two 6 six sided dice, to give a possible output of 2-12. Given a java.util.Random instance r, the output of one roll would be: ...
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### What Java actually stores inside Keystore when generating Keys?

When we use Keytool to generate a Keystore to store Private/Public keys, what Java actually stores inside the Keystore file ? I ...
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### Problem description “SAFE” [on hold]

So this is the problem, sorry for the bad img quality. The answer which i don't know is 10 chars long. And there are thease 3 safe knobs with numbers inside them. I have been trying to solve it,yet ...
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### Designing hash function in space-efficient identity based encryption

Let $n$ be an RSA-prime and we know prime factorization of $n(=pq)$. The hash function is the current context maps from a given user identity(id) to a positive integer less than $n$, whose jacobi ...
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### How many characters per block in an El Gamal ECC cryptosystem?

While I look for how many characters that can be encrypted using the The elliptic curve ElGamal cryptosystem. of each block found for these lines. But I can not understand Actually in our case we ...
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### Which Encryption Method is used for this stream cipher? [on hold]

Plaintext: 378734493671000 Encrypted: +VZyZlAHP6HAgoaPBrBz +VZ is common on all data there, so encrypted data might be yZlAHP6HAgoaPBrBz I think this is stream cipher? Could anyone tell me which ...
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### Find the encryption method from the cipher and plaintext [on hold]

I have been given iogdaybDfD which is a cipher of the word narcolepsy. I need to find the type of encryption that has been applied to narcolepsy to encrypt it to iogdaybDfD. Could anyone advise on how ...
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### CP-ABE: structure of the secret key SK

I am working on Ciphertext-Policy Attribute based Encryption (CP-ABE) and I need to understand how a secret key looks like. For example, assume that the universe of attributes is defined to be ...
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### Interactive assumptions not falsifiable?

Can someone explain why an interactive assumption is not falsifiable? Maybe I'm misunderstanding what the statement means, but isn't even a non-interactive assumption interactive, but just with a zero ...
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### Java RSA/ECB/PKCS1Padding encryption with .NET [on hold]

I need to encrypt a password on a web site developped in .NET using a public key. The public key is delivered through a Java web service with the information: The key is a RSA key to be used with ...
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### Malicious DH groups

Can an attacker construct a DH group, large enough to be considered secure (say, a modulus of 2048-bits), such that the group appears safe, but the attacker is able to solve the DLP in the group ...
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### Full Disk Encryption Alternative [on hold]

Since developers of TrueCrypt discontinued their software, i'm looking for a alternative. It should be pre-OS, so that just after Bios, the Password is requested. Like in TrueCrypt. I took a look ...
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### Crypto Challenge.sucked [on hold]

The solution was hardened using MD5(MD2(SHA1([a-zA-Z]{6}))). Now crack this: e24b02c81cabe0d4af45f9ceaccde2c7 i couldnt crack it.
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### special public keys and modulo n

I just picked up cryptography and have some questions on RSA cryptosystem: Say there are two public keys (n, e1), (n, e2), e1 is coprime to e2. They share the same n. Is it possible to find the ...
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### How can I start the following crypto project?

(Cryptography: encrypting files before storage in the cloud): The project consists of a software implementation of a method to pre-process a file before storing it on a cloud storage server so that ...
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### proving the security of 1 out of 2 oblivious transfer using AND function

Hello ladies & gentlemen, I need to improve the security of 1-out of 2 oblivious transfer using AND function method with a given info. use one-out-of-two oblivious transfer as building block, ...