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## How can I use AES to encrypt a single block?

I want to use AES inside another crypto algorithm, and as such I need to encrypt single 128 bit blocks at a time inside a for loop. However the examples on MSDN which show the uses of some of the ...

1 answers | 8 mins ago by erotavlas on stackoverflow.com

## How to loop a numerical value in a range when reaching the end of the range

I am trying to create a basic encryption program that converts character values to numerical form, adds on a "key" and then converts them back to char form, thus encrypting the word. However I ...

## Why do we require a CSPRNG's output to be indistinguishable from true random?

Everywhere I read lists as a requirement that, to qualify as a CSPRNG, the output has to be indistinguishable from true random. But nobody bothered to explain why this cryptographers impose such a ...

## hash functions preimage and second collision resistance

A hash function H is secure in terms of pre-image resis-tance. Does this imply that H has second pre-image (aka weak collision) resistance?

## Select two distinct primes each with 6 binary digits and use them to design an RSA cryptosystem.

Describe how to design an RSA cryptosystem based on primes p = 13 and q = 7. That is, propose the public key and the private key. Encode the message 100101 and then decode it. I'm mimicking my ...

## How does every system or server get a different hash function to store passwords

as I understand it, user passwords must be stored as hashes instead of encrypted, because an attacker cant deduce a password from its hash, while he can deduce a password from its encryption, if he ...

## Compile latex from python

I have made some python function for compiling passed string as pdf file using latex. The function works as expected and has been quite useful, therefore I look for ways to improve it. The code which ...

## Unseen.is encryption claims revisited with their proprietary, patented “xAES” algorithm

I had asked last year about the encryption claims by the webservice called https://unseen.is. The very same service that had claims of "beyond army level encryption", "4096 bit keys" etc. This is the ...

## The Drunken Bishop

In public-key cryptography, a public key fingerprint is a short sequence of bytes used to identify a longer public key. In SSH in particular they can be used to verify that a server is in fact ...

## How do I play back CENC-encrypted MP4 video using the HTML5 <video> tag?

I'm trying to play a video that I've CENC-encrypted using MP4box with these options: MP4Box -crypt drm_file_gpac_clear.xml BigBuckBunny.mp4 -out BigBuckBunny_cenc.mp4 Where the XML file specifies ...

1 answers | 2 hours ago by crg on stackoverflow.com

## odd way of rendering math formulas in wikipedia

I am encountering a strange problem that has stopped me for several hours. Wikipedia shows math formulas as LaTeX code but I don't have this problem in other sites like Math SE. The photo shows ...

## Reversing encryption algorithm that XORs each character with another in the string, using parity to control offset

I've reversed the following algorithm from a challenge binary I'm investigating: def encrypt(plain): l = len(plain) a = 10 cipher = "" for i in range(0, l): if i + a < l - ...

## Problem with applying threshold scheme

For a report on threshold signature schemes, I have to explain a threshold signature scheme and give a simple example with numbers. A threshold signature scheme is a scheme in which a network of n ...

## Encrypt & decrypt in PHP: fast, short, valid HTML ids & URL safe

Can anyone suggest a versatile PHP encrypt/decrypt algorithm that encrypts in the following way: it's fast it's short, similar to YouTube's video ids can be used as a valid id (an elements ...

4 answers | 4 hours ago stackoverflow.com

## Is there an upper bound to the private exponent in RSA?

In the RSA algorithm, we choose $p$ and $q$ as prime numbers and we select a value $e$ which is coprime to $\varphi(pq)=(p-1)(q-1)$. Then we calculate $d:=e^{-1}\bmod\varphi(pq)$. My question is: ...

## Where can be ECDsaCryptoServiceProvider class found

I've been following this sample about singing xml documents with c# using RSACryptoServiceProvider. What I need is to use this sample with ECDsaCryptoServiceProvider, found here: ...

## Does SRP also authenticate the server to the client?

The Secure Remote Password (SRP) protocol lets a client prove to a server that it knows a specific password without revealing that password to the server. The server stores a cryptographic verifier ...

## lcm versus phi in RSA

In textbook RSA, the Euler $\varphi$ function $$\varphi(pq) := (p-1)(q-1)$$ is used to define the private exponent $d$. On the other hand, real-world cryptographic specifications require the ...

## CryptoAPI RSA: CryptDecrypt decrypts only one time, after came NTE_BAD_DATA

I have write the programm which encrypts/decrypts memory buffer of custom length. Ecryption ends well; but my decryption code decrypts data only one time at any buffer position, wich corresponds to ...

2 answers | 5 hours ago by Mykola on stackoverflow.com

## Perfect hash function

Is a perfect hash function always bijective ? In Wiki "In mathematical terms, it is a total injective function" but it does not mean, that it is bijective.

## Adding points on an elliptic curve

I'm trying to work out a problem from a previous exam in Cryptography regarding elliptic curves. I can add points on an EC using the formulas given, but the suggested solution to this exam problem I ...

## What are the implications of differences in confidentiality timeliness?

From a security standpoint, what are the differences that must be addressed between data with a day-long confidentiality timeliness and data with timeliness of a year or more?

## MathJax 2.6 beta

Today we are entering the public beta phase of MathJax v2.6 beta. We are asking you to try out the new output. Be aware, this one will offer a new set of fonts. I will allow Peter Krautzberger to ...

## How was privacy and cryptography looked upon in early part of the interweb

As people here are all crypto-experts, I am hoping and expecting that some or most of the people would also be privacy advocates as privacy and cryptography are nothing but two sides of the same coin. ...

## What are the implications of differences in data confidentiality timeliness?

From a security standpoint, what are the differences that must be addressed between data with a day-long confidentiality timeliness and data with timeliness of a year or more?

## Perfect Secrecy of AES file Encryption

Why does AES file encryption not ensure perfect secrecy? I understand that $\Pr[E(K,M_1)=C_1] = \Pr[E(K,M_2)=C_2]$ given $M1\neq M2$ holds for perfect secrecy of a scheme. However, this seems to hold ...

## MD5 hash generator

I made this code for a simple WinForm for my school project where I want to add other hash and encryption algorithms. I have made it following the algorithm of the official RFC 1321 and the Wikipedia ...

## Can a PNG be encrypted without losing the exif data?

I've been working on this Reddit puzzle: http://www.reddit.com/r/playitforward/comments/1v6jfh/contest_first_one_to_solve_this_riddle_gets_my/ and most of users in the thread are stumped. Full ...