Encryption is the process of transforming plaintext using a cipher to make it unreadable to anyone except those possessing the key.
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Secure way to transfer data over NFC?
I am currently writing a payment system to accept payment details from an NFC enabled smartphone (BlackBerry 9900) to a Windows client (C#.NET)
I am currently having two issues relating to security:
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99 views
Does anyone know which encryption scheme produces the following output? [closed]
My company is using software that stores an encrypted database password in a publicly accessible file. The encrypted version looks like this:
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2answers
331 views
Can md5 be used for encrypting data?
I know that md5 shouldn't be used for password hashing because of collisions and possibility of making dictionary attacks e.g. using rainbow tables. But what about ...
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1k views
Why RSA encryption key is based on modulo(phi(n)) rather than modulo n
While calculating RSA encryption key we take modulo(phi(n)) rather that modulo(n). I couldn't understand why its so?
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1answer
1k views
How do I correctly derive a Key and IV?
Mainly I'm trying to understand how to correctly create the Key and IV for use with the .NET Implementation of AES (AesManaged class).
This encryption code will be used in conjunction with existing ...
3
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3answers
856 views
Simple/beginner level explanation of salt
I'm a beginner to cryptography and looking to understand in very simple terms what salt is, when I might need to use it and why I should/should not use it. Can anyone offer me a very simple and clear ...
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Encryption/ciphers/codes in Chinese
I am quite curious as to how you can perform simple encryption for the Chinese language.
Saw a similar question related to encryption/Chinese here: About cryptography in a character language, ...
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2answers
202 views
Provable Encryption
Is it possible to encrypt data in a way that it can be proven that the data is encrypted, without revealing the key?
Alice chooses some plaintext, then she encrypts it with a certain scheme. She ...
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Is it neccesary to delegate / impossible not to delegate your cryptographic operations? [closed]
According to this guy SkyNet is coming. Should people delegate encryption/decryption to hardware and software which was not 100% their own design?
Compare with the original formulation of Kerchoff's ...
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How can one securely generate an asymmetric key pair from a short passphrase?
Background info:
I am planning on making a filehost with which one can encrypt and upload files. To protect the data against any form of hacking, I'd like not to know the encryption key ($K$) used for ...
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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 ...
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2answers
451 views
suggestions for cryptography projects for an ece 3rd year student
I am an electronics and communication engg student currently doing my 3rd year second semester. i am interested in info coding and the security aspects of it. As an ECE student i want to know what is ...
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333 views
Is it possible to create an easy to use encryption/decryption method that will never be comprimised?
In the comments of the question "Why programming languages don't provide simple encryption methods?" the following statement was made:
A well thought out, tested and understood standard that has ...
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901 views
Why programming languages don't provide simple encryption methods?
In c#, there is a namespace called System.Security.Cryptography and there are many classes in this namespace, which help developers encrypt and decrypt data. ...
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2answers
598 views
How can I break REDSHIRT / REDSHIRT2 encryption?
Recently, a user on Gaming.SE asked a question about whether the user password in the video game Uplink could be modified after being initially set. The game does not contain an option to change the ...
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2answers
214 views
AESManaged Trade Compliance Issue in United States
I am currently using AESManaged encryption for my silverlight application. Does AESManaged encryption have a severe trade compliance issue in Bureau of Industry and Security in terms of shipping the ...
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1answer
220 views
Verifying the integrity of ciphertext using the cleartext hash?
I want to be able to verify the integrity of a ciphertext by providing the cleartext hash, for this to work it would need to:
$$hash(crypt(cleartext)) = f(hash(cleartext))$$
Where $f$ is an ...
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4answers
294 views
Can I determine if a user has the wrong symmetric encryption key?
We're using the Objectivity/DB object database with a custom encryption plugin that encrypts serialized objects on disk. Encryption uses AES with a shared secret key held by all users. I would like to ...
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How to choose a padding mode with AES
Depending on the framework you are using, there are various padding modes that can be used with AES encryption. For example, with .NET we can choose PKCS7, ISO10126, ANSIX923, Zeros or None.
I ...
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617 views
What is the importance of Modular arithmetic in cryptography?
Why do we use modular arithmetic so often in Cryptography?
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2answers
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How do I solve this RSA instance for m?
How we can solve this equation and get the value of M?
$$8 = M^{13} \mod 33$$
not a computer program, but a mathematical operation.
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3answers
193 views
What other one-way functions are used in cryptosystems?
For RSA and El Gamal (and most other public key cryptosystems), one of the key ideas is that factoring and finding discrete logarithms are hard. There are other systems that rely on certain properties ...
3
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1answer
130 views
Does hash_df use binary or an ASCII hexadecimal representation for numbers to be passed to the hash function?
I'm implementing the HASH_DRBG algorithm.
As per NIST-SP800 90 document for HASH DRBG Generation, section 10.4.1 "Derivation Function Using a Hash Function (Hash_df)", the Hash_df algorithm contains ...
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1answer
310 views
Are there two-way encryption algorithms that include a work factor?
I recently learned about the hashing algorithm bcrypt, which allows you to specify a "work factor" for the hash which can be incremented to stay ahead of Moore's Law. I understand there are some other ...
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2answers
207 views
What is the appropriate public key encryption for secure coin flipping?
I quote Bobby's question here since I encountered the same one...
Random Coin Flip using ElGamal and a Trusted Party
Consider the following protocol for two parties to flip a fair coin.
Trusted ...
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1answer
292 views
Hash or encryption function for challenge-response protocol?
Say I have an authentication protocol where the shared secret is never transmitted. The server passes a challenge to the client and the client calculates a response using an algorithm where the ...
2
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2answers
801 views
How to distribute session keys in public key cryptography?
In public key cryptography we can also use session keys which are symmetric. How do the sender (say a server) provides this session key information to its clients?
If the sender (here server) ...
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2answers
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Where is the proof of security of Diffie's cipher?
There is an apparently provably secure cipher that was proposed by Diffie, but enhanced by R.A. Rueppel. The scheme, which was mentioned in Applied Cryptography, works like this:
Measure the length ...
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1answer
405 views
How can I make my cipher show the avalanche effect?
I am a beginner in cryptography. I designed an password based encryption-decryption algorithm, which uses a random salt and a password to encrypt a message. I'm using SHA-512 for hashing, matrix ...
6
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1answer
580 views
AES and perfect ciphers
I'm taking a crypto class this semester and after learning the definition of a perfect cipher. I started wondering how this definition applies to AES.
Obviously AES isn't a perfect cipher, since the ...
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1answer
451 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 .
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Using a Non-Random IV with modes other than CBC
The weakness CWE-329 is an interesting problem with CBC mode. However, does this same weakness affect the other modes of operation that rely upon an IV such as: PCBC, CFB and OFB? My gut feeling is, ...
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3answers
539 views
Does knowing common prefixes help crack blowfish?
I have strings that are if the form:
{static data}{changing data}
The beginning static data part is around 20 characters and is common to all strings. The last ...
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3answers
328 views
Trying to find a different DES encryption system explanation
I need a mathematical explanation of what does the DES encryption system really do.
This means I need more explanation than the one that offers FIPS, which is more an explanation for computer ...
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3answers
306 views
Encryption technique performance evaluation
I've come up with a light weight bit wise encryption algorithm and seems good. Ive tried it with text and image input. But I've the following questions I would like to ask
What do you think of bit ...
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2answers
239 views
101: Advanced Access Content System (AACS) and Subset Difference techniques for Broadcast Encryption
I'm trying to get a grasp on AACS and Subset Difference for a project I'm working on and am having a hard time coming up with a technically valid layman explanation, let alone implementation.
Is it ...
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1answer
1k views
Avalanche effect in DES
I couldn't understand the avalanche effect in DES. Could someone explain how avalanche effect happens in DES
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1answer
434 views
Encrypting and obscuring data between site/user without SSL
Im trying to figure out what the best way to encrypt data sent between a webpage and the user(both ways) is, when hosted in an environment that doesn't support SSL. The purpose of encryption would be ...
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2answers
565 views
What is the purpose of four different secrets shared by client and server in SSL/TLS?
I was looking through the working of SSL V3, and found that a connection state is defined by a set of things, including
client write mac secret,
server write mac secret,
server write key,
client ...
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1answer
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Can CBC ciphertext be decrypted if the key is known, but the IV not?
Let's say that there is a binary file encrypted with AES in CBC mode (i.e. using a key and initialization vector). If key is known, but IV is not, is it easy to fully decrypt the file?
How hard is ...
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2answers
856 views
Why do we need special key-wrap algorithms?
Wikipedia says:
Key Wrap constructions are a class of symmetric encryption algorithms designed to
encapsulate (encrypt) cryptographic key material.
We are using these algorithms to encrypt ...
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1answer
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How does a key wrapping like RFC 3394 secure my cryptographic keys?
So I'm messing around in the BouncyCastle library with the RFC 3394 AES Key Wrap engine and I'm trying to understand the benefit of it.
The problem I'm running into is how to store keys securely on a ...
4
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3answers
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Is Blowfish strong enough for VPN encryption?
I'm looking at an OpenVPN connection between two sites configured to use 128 bit Blowfish in CBC mode, and trying to figure out how to assess the strength, but I just don't know enough of the maths.
...
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2answers
654 views
Decrypting DES with decrypted and encrypted data
I got two 8 bytestrings
One which is decrypted is:
FF FF FF FF FF FF FF FF
and one which is encrypted is:
16 05 78 B0 0A C2 78 7F
Encryption mode is CipherMode.ECB
I need the key used in DES ...
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1answer
261 views
If the PSK is known, is it possible to decrypt traffic from other clients in a WPA2 wlan network?
If in a public WLAN WPA2-PSK is used, but the PSK is more or less publicly available, does this mean that an attacker with that PSK can easily decrypt wlan traffic from/to other clients of that WLAN?
...
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3answers
269 views
Does the XML Encryption flaw affect SSL/TLS?
A "practical attack against XML's cipher block chaining (CBC) mode" has been demonstrated:
XML Encryption Flaw Leaves Web Services Vulnerable.
Does this weakness of CBC-mode which is used here also ...
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2answers
187 views
How can I encrypt more than 64 bit with the Data Encryption Standard?
The Data Encryption Algorithm is designed to encipher and decipher blocks of data consisting of 64 bits under control of a 56-bit key.
If my data is more than 64 bits, (suppose 66 or 67 bits), will ...
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3answers
793 views
Is the CBC weakness in XML Encryption a new discovery? Are other applications vulnerable?
The RUB in Germany reports that XML encryption is broken. This is essentially the W3C standard for protecting XML documents from prying eyes.
Does this mean that an attacker can only see a single ...
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2answers
276 views
Deniable Encryption from simple primitives
Is there a deniable encryption scheme $M = E(p_1,k_1,p_2,k_2,...,p_n,k_n), p_j = D(M,k_j)$ of $n$ plaintexts $p_1,p_2,...,p_n$ and $n$ keys $k_1,k_2,...,k_n$, such that we can fix $D$ to be a known ...
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2answers
153 views
Getting the encryption method and key from the encrypted data and the raw data
I have some pairs of plaintext and ciphertext data, from which I need to be able to decrypt the other passwords stored in the database.
The password field typically contains something like
...
