Cryptography is the practice and study of logical means used to achieve information confidentiality, integrity and authenticity. It covers, among other things, encryption (making some data unreadable except for those who know a given secret element, called a key), data hashing (in particular for ...

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Hashing with unknown salt security

First off, this question is not about password hashing, my requirements are different. In particular I fully agree that salts are not useful for adding cryptographical complexity in password hashes, ...
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0answers
75 views

How secure is Wire?

I have stumbled upon this replacement for Skype, which claims to take privacy seriously. They recently open-sourced their client-side code. Is Wire secure? What data can be intersected and read by a ...
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2answers
105 views

Encryption - RSA vs. AES

I have a question regarding encryption and whether to use symmetric or asymmetric encryption. The idea is to implement a form of data encryption in a variety of software. This data will be exchanged ...
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4answers
127 views

Which cryptographic algorithm should be used on client side to encrypt file before uploading to a cloud which is only for storing purpose?

I want to develop a website which will take the files from my computer encrypt it with my key and upload it on cloud which is only for storage purpose and decrypt it after downloading it on my ...
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0answers
299 views

Reverse the encryption (part of the Labyrnith ctf challenge) [closed]

So my friend and I were trying to do this ctf challenge here http://labyrenth.com/ and when we were trying to solve the first part of the "Threat" challenges we stumbled upon a challenge we have no ...
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1answer
15 views

HPET effects on CSPRNG for Linux OS

HPET or High Precision Event Timer is a hardware built-in clock source available in most processors. I would use the computer to generate CSPRNG and do cryptographic operations. My question is: Is ...
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1answer
58 views

Do current eCommerce systems provide sufficient security? [closed]

eCommerce systems are increasingly gaining importance in modern digital markets. Since most electronic transactions occur on a range of platforms, securing e-commerce transactions using Mobile Agents ...
2
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2answers
93 views

TLS Version specific cipher suites

I have come across that GCM, CCM, SHA-256 and SHA-384 Cipher suites are TLS 1.2 only. So TLS handshake can not be performed with lower TLS version using these suites. I am trying to figure out ...
2
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3answers
58 views

Does a certificate authority use different private keys?

I was wondering whether a CA has different private keys to sign certificates with? Is there a risk of crypto-analysis (or something similar) when a CA signs thousands of certificates with the same ...
1
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2answers
56 views

Why are primes reused in Diffie-Hellman key exchanges?

Reading about the Logjam attack, I learned that Diffie-Hellman exchanges often* rely on the same particular 1024-bit key. I understand that back when DH was invented, even 512-bit keys were considered ...
1
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4answers
108 views

What exactly is a key in cryptography?

After researching and reading I am not sure if I completely understand it. To my knowledge, a key is a password used to decrypt a message. However, the confusion comes in when it comes to the public ...
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0answers
34 views

which type of encryption is RWJKeLBJTBfDc? [duplicate]

which type of encryption is RWJKeLBJTBfDc ? and how can you detect it
2
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2answers
188 views

Cloning problem of VM license keys

How do software companies ensure that their product or app can only run in a given number of bare-metal or VM instances? I'm curious about the cryptography behind the scenes. What prevents a user from ...
4
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1answer
111 views

ProtonMail: Would it not be much better if each user had their own private key?

ProtonMail keeps the encrypted private keys of all their users in their servers. The mailbox password for each user decrypts this private key, which is known only to that user. Would it not actually ...
4
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0answers
31 views

UEFI Firmware integrity measurement

we know that UEFI measures the OS bootloader image integrity every time we power on our computer, if Secure Boot enabled. With the growing attacks and discoveries of UEFI vulnerabilities, the ...
2
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0answers
39 views

How do (broadcast-only/passive) RFID licence plates assert their identity?

I would have guessed by some kind of challenge-response, but there seem to be many claims of 'passive' or 'broadcast-only' tags in the plates. For example from http://www.e-plate.com/security.html: ...
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0answers
34 views

Is it safe to combine System.Random with cryptographically secure pseudo-random number generators? [migrated]

Have a look at the following codesample written in C#: private static byte[] GetRandomBytes(int size) { byte[] buff = new byte[size]; // Create an array of crypto-secure random numbers ...
2
votes
1answer
60 views

ECC for future IoT devices?

Elliptic Curve Cryptography(ECC) is one of the powerful cryptographic methods that requires less computational effort. IoT requires a cryptosystem that secures smart services and applications (5As i....
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3answers
110 views

Where to find current information on cipher suite strength?

I am hardening the configuration for my /etc/ssh/sshd_config and have a few choices for Ciphers: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,...
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2answers
172 views

Unencrypt Data Encrypted by Cryptolocker Virus [duplicate]

A while back my computer was encrypted by the cryptolocker virus. I ended up taking an image of the encrypted drive and then formatting it and installing a new operating system. Since I have the ...
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2answers
84 views

Is is possible to shuffle an AES ciphertext without owning the key for it?

I would like to know if it is mathematically feasible to change an AES(CBC) ciphertext and IV without owning the key, so that the ciphertext would look totally different while still decrypting to the ...
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0answers
27 views

If a HSM RNG is FIPS 140-2 compliant, does that imply FIPS 186-2 compliance also?

If the RNG of an HSM is said to be compliant to FIPS 140-2 (approved DRBG - SP 800-90 CTR mode) does also imply that it is compliant to FIPS 186-2?
2
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1answer
67 views

What does “probability space is over coin flips of algorithm M” mean?

In the book The Algorithmic Foundations of Differential Privacy by Cynthia Dwork, Aaron Roth on page 16 (actually page 20 in the pdf viewer) it says at the very bottom of the page: Definition 2.2 (...
2
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0answers
12 views

hash function notations and existing cryptographic hash algorithms [migrated]

I am implementing Role-based access control by referencing the paper Enforcing Role-Based Access Control for Secure Data Storage in the Cloud. In page 6, they have mentioned to choose hash functions ...
0
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2answers
86 views

Which of AES modes are safer and faster for transferring data over the network?

I have using Crypto++ in Qt and use of AES Algorithm for encrypting files. I know about AES modes and their applications. I have use of StreamTransformation method for encrypting files in CBC and EAX ...
3
votes
1answer
79 views

Recommended Crypto Security Setup (Implemented Algorithms)?

Firstly I'm not a crypto expert, however I know how to use algorithms that other people have defined before in practical usages, that is, as long as they live up to their promises. The thing is that ...
2
votes
1answer
85 views

Android N - Security Crypto Provider is deprecated

As mentioned in "android developer's blog" , http://android-developers.blogspot.in/2016/06/security-crypto-provider-deprecated-in.html , security Crypto provider is deprecated on Android N. And also ...
3
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2answers
101 views

Does a hash of a 32-bit integer make a better hash salt than the integer itself?

I have a scenario where I already have a table of resource passwords stored as unsalted 128-bit hashes. I'm unable to force owners to provide new passwords, so I'm trying to mitigate the situation by ...
7
votes
1answer
56 views

Does the use of a smartphone's Secure Element really offer security benefits to a banking app?

My bank's Android application allows users to perform financial transactions without the use of the physical token generator (which requires an ATM card to be inserted and a valid PIN to be provided) ...
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2answers
135 views

How long would it take to generate a file to match a hash? [duplicate]

A individual file only has a single hash of any specific byte length. But an individual hash can represent a large number of different files. Given a 256 byte hash, how long would it take to ...
3
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0answers
67 views

security of libgcrypt when cross-compiling for windows?

Looking at libgcrypt, specifically secmem.c it seems that it does not account for windows-specific memory handling (e.g. VirtualLock) and in fact there is a very troubling comment: #elif defined (...
4
votes
2answers
75 views

Is CHAP authentication still secure?

Assuming the use of the default hashing algorithm MD5, is CHAP authentication still secure? I appreciate that MD5 is considered broken in terms of collision resistance, but I also understand that in ...
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2answers
37 views

Can an RSA signature be changed given the public key?

If I were to post on a forum (with potentially malicious administrators) my public RSA key and a small string of text that was signed with the corresponding private key, could someone with access to ...
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4answers
218 views

Roll your own encryption - with a twist

I am familiar with Schneier's Law: Any person can invent a security system so clever that he or she can't imagine a way of breaking it. I have read the many posts on this exchange littered with ...
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0answers
37 views

ISO 9564 Approved Encryption Algorithms for PIN, why symmetric block ciphers?

I am currently researching best practices in designing a potential PIN management solution for a financial services application and began looking into ISO 9564 as a source of requirements. One of the ...
0
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2answers
127 views

I want to encrypt certain entries in a database. Is this a good plan?

I'm working on a web app and want to offer the users the option to "encrypt" their account. This wouldn't encrypt everything related to them in the database. Just certain critical fields. I've ...
0
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0answers
27 views

How to determine which form of encryption is used? [duplicate]

I have an application which is developed using classis asp. The password is encrypted in the following format - LHFJOJ1234 Can anyone tell me which format is this? I don't have the source code. So ...
39
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7answers
5k views

Exploiting MD5 vulnerability in this PHP form?

I've been practicing in security-related topics and I came upon this problem which I don't understand at all. You receive a form with one input named pass, and this is the code you need to bypass: &...
1
vote
2answers
75 views

Detecting a Crypted executable that is supposed to bypass antivirus [closed]

I've seen many Crypters being advertised to bypass antivirus and they work. The malware crypted by the Crypter evades antivirus detection. How would you programtically or using a tool reliably ...
1
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1answer
213 views

Partial decryption using untrusted decryption service

While there are ways to encrypt and decrypt information, most of these seem quite computation-heavy. Because of this I am thinking about splitting decryption into two parts - one is computation heavy ...
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1answer
55 views

How does (Py)NaCl work exactly?

At the moment, I deal with PyNaCl (Docs) and have a question about it: My situation is that I want to create a server that interacts with clients. Both the server and the client will have a long-term ...
0
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4answers
285 views

Which layer of OSI model does end-to-end encryption and decryption happen in a network? Why?

I thought it happens at Layer 6, but some resources state that it happens at either Layer 3 or 4.
1
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0answers
22 views

Substitution Table in TKIP

In TKIP Encapsulation, we divided the per packet key mixing process into two phases. In phase 1, we are taking three inputs i.e temporal key (128-bit session key), transmitter MAC address (48 bits) ...
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0answers
49 views

Choosing Key and IV in AES-256

I am working on a real-life project for a firm. I have to encrypt data using AES 256 as per specification. I want to know how are the key and IV are really chosen in real world projects. /dev/urandom ...
0
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2answers
182 views

C# .Net most secure way to store RSA Key Pair in Windows

At the moment I am looking into the most secure way to store a private RSA key on Windows. Making it as much usable for the end user as possible, while keeping the security to its highest. As this ...
1
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1answer
56 views

Securing confidential information between users

I know there are several issues about encryption, but my case is slightly different Users have confidential information stored on their device They have a RSA key pair The information must be ...
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1answer
41 views

Question how PPP with CHAP for Cisco works

I'm learning to configure a simple PPP link with CHAP authentication for two Cisco routers. I'm trying to make sense of how router makes sense of the configuration in this example, as the logic of ...
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0answers
21 views

What is purpose of fipscheck utility and fipscheck library on Linux?

So I am messing around with dracut and I am trying to get my Linux system in FIPS 140 mode by passing fips=1 to my linux kernel at the boot time from grub. However, I got confused on why dracut ...
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0answers
29 views

How crypto module integrity checks mandated by FIPS 140 standard help to make Linux based appliances safer?

After browsing dracut and hmaccalc rpm package source code I found out sha512hmac utility that is used to do do integrity checks for linux kernel (and other binaries) from initramfs boot stage uses ...
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3answers
266 views

Disadvantages of using same key for encryption and decryption in symmetric cipher? [closed]

In a symmetric cipher, the same key is used for encryption and decryption. What are some disadvantages of using the same key?