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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Can there be two certificates with a same serial number in the world? [duplicate]

Recently I came across this odd question. I hope, Serial number is unique across certificates signed by a particular CA. So is there any chance that two different CAs sign two different certificates ...
6
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1answer
52 views

Terminology for attacks of extracting an application's shared library and using it stand-alone

Let say I got a library to read/write files securely on the hard disk (encrypt before writing and decrypt to read back). If the library is severely obfuscated, attackers may be intimidated. So they ...
3
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2answers
145 views

WebCrypto algorithms and differences with other crypto libraries

I was looking at the WebCrypto crypto libraries coming form the W3C. Looks like only a few cryptosystems are supported, including AES-CBC, AES-CTR, AES-GCM, and RSA-OAEP. https://developer.mozilla....
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1answer
320 views

Is keepass random password generator fully secure and trustworthy?

Am I safe using keepass for generating passwords? For example my accounts, am I safe using a keepass generated password? Could my future keepass master-keys be safely generated in keepass? What method ...
2
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2answers
143 views

Choosing between SSH and HTTPS for executing script using McAfee ESM Nitro

We intend to use McAfee ESM Nitro (SIEM) for security monitoring of our infrastructure servers. To bring automation in system administration of our servers, we have developed some applications in-...
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0answers
62 views

Token-based authentication for specific requirement

We have the following requirement for creating a token in .NET to be used in providing a challenge token and an actual authentication (auth) token. The auth token will then be used to authenticated ...
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1answer
117 views

Storing encrypted data readable only by user but created by server

Context I'm actually creating an automated security scan application, meaning that every user will be able to scan their own website (the property verificationpart is done) and get flaws found in ...
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1answer
88 views

Steganography concept - How to check my implementation? [closed]

I have written my own software to do Steganography. Basically, I am dividing the message (text) into bits and then hide them into pixels in jpg. After that I am saving the bitmap into .png (because ....
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2answers
249 views

Generate CSR and private key with password with OpenSSL

I am using the following command in order to generate a CSR together with a private key by using OpenSSL: openssl req -new -subj "/CN=sample.myhost.com" -out newcsr.csr -nodes -sha512 -newkey rsa:...
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2answers
71 views

Public Key Infrastructure: Sending data securely to CLIENT?

Ok, so been looking up public key encryption and using it a bit around some of my web applications. From some testing, I understand that the server contains two keys and sends the public key to the ...
3
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0answers
83 views

Is there a benefit in measuring randomness? How would it be done?

Is there any benefit in determining how random a given file, stream, signal is? I guess this would be useful to determine If something is (poorly) encrypted To verify the proper encryption of a ...
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4answers
1k views

Possible to read strength of encryption?

With the recent talks of governments trying to weaken encryption, I had a question about how they would implement it. For example, let's just say that the government banned anything above AES-128. I ...
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1answer
116 views

Resetting the Windows RNG

According to this research, Windows seems to produce the same sequence of random numbers indefinitely when a process is kicked off before a VM snapshot is taken. This is a huge issue obviously when ...
48
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9answers
13k views

Writing my own encryption algorithm [closed]

I am currently studying IT at college (UK college aka not University) and the coursework is boring me to death. I have been coding for quite a while now mainly in OO languages such as C# and Java but ...
1
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1answer
256 views

Crack 512-bit RSA encrypted messages without a private key?

I was wondering if it would be possible to crack a message that was encrypted with 512-bit PCKS1 encryption with the public key. I am doing a project for our science fair type thing at school and have ...
3
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2answers
176 views

In Ephemeral Diffie Hellman Key Exchange - what is actually ephemeral?

Just starting to learn about Diffie-Hellman, and it seems simple enough, but I am struggling to find any resources that explain in an Ephemeral Diffie Hellman Key Exchange, what it is that is actually ...
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2answers
181 views

Encrypting unique fields in a Database

I'm still a beginner to cryptography and want to know what the best practice is for solving the following problem: I'm creating an application with the requirement that a user's email address must be ...
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0answers
36 views

Is there a point in cascade encryption? [duplicate]

I was reading the other day about some programs (ex: DiskCryptor), and with my limited knowledge of cryptography.. I started wondering about cascading encryptions (ex: AES-Twofish-Blowfish). Assuming ...
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2answers
164 views

Using a password hash…as the password? [duplicate]

Ok, this is probably a really stupid idea, but I can't really see why it would be a bad idea. Maybe someone can enlighten me. Why couldn't you enter a password good hashing algorithm like bcrypt, ...
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2answers
307 views

How Does Telegram's Identity Verification Work?

Note: please refrain from commenting on Telegram's design of OTHER parts, as it will distract from the stem of the question. Background: Signal (Previously, "TextSecure" app) uses specific "Your ...
0
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1answer
252 views

How can I detect if hashes are salted? [duplicate]

Is it possible to detect hash function of a hash if I don't have access to PHP code? I know that if a hash is some kind of MD5, but I don't know if there is salt etc.
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1answer
47 views

«Secret ballot» requirement for a distributed e-voting system

There are lots of discussions about electronic voting vs paper-based voting and technical concerns about it. So here's another one. There are some concepts that are very similar to cryptocurrencies ...
3
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1answer
80 views

Using the password, among other values, as key data in two-factor authentication

I'm writing an implementation and a thesis about two-factor authentication, and am currently doing some research. I'm currently looking at an implementation for deterministically generating a ...
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4answers
163 views

Must an encrypted hash value be bigger than the password it was generated from?

I was reading a book called Introduction to network security theory and practice, and I found the following paragraph: Rainbow Tables A rainbow table is a table of two columns constructed as ...
5
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1answer
124 views

Browsers and HTTP Public Key Pinning

The strength of HTTP Public Key Pinning (HPKP) is that the browsers are saving the keys from the HTTP header and can check in the future if the certificate from the website is valid. I have two ...
10
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1answer
272 views

What benefits do Hardware Security Modules provide when keys are not stored inside them?

I'm researching a project that makes use of cryptography. It is a .net application with keys stored in a sql server database. For cryptography, the project uses a Hardware Security Module similar to ...
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3answers
2k views

Do we still need to encrypt/decrypt data in Application Layer, despite using TLS/SSL?

Actually I got some projects from my ex-colleagues. These are App-Server TCP socket based applications. I noticed that some of auth/login interactions are using RSA/AES encrypt/decrypt as I know, if ...
2
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3answers
64 views

Stacking Encryptions (Stream over Block)

I am reviewing the code for a product our team developed where credit card information is stored in a local database in the event of no internet connection and came across the encryption methods. The ...
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1answer
41 views

Quantum Computation and its threats [duplicate]

Since Quantum Computers has potential to become super computers of next generation. will that make cryptography obsolete..?
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1answer
88 views

why don't we measure the strength of crypto against the cost it would take to crack it? [closed]

I hear all the time how many hours it would take to break a certain type of encryption. I think this may be the wrong metric to look at ever since scaling became an easy to implement solution. Sure ...
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2answers
194 views

What are some Linux commands for genrating and verifying digital signatures?

I am attempting a workflow to exemplify the process of digital signature using asymmetric cryptography. If I understand correctly then the public key and the private key in an asymmetric ...
3
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3answers
84 views

Decrypt SSL Connections established by a Host I have adminsitrative privileges on

I want to decrypt a SSL connection that is established by an unknown binary file on a Windows 7 Computer. This binary doesn't exist on any other computer on our network and establishes SSL encrypted ...
2
votes
1answer
100 views

Security risks of symmetric encryption with compression for database data

I would like to compress data before encrypting and storing it in a MySQL database to reduce especially bandwith requirements. In the future, the DB may be accessible via a web interface. Various ...
1
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1answer
327 views

Bypass SSL Certificate Pinning using SSL Vulnerablilities

I am wondering if it could be possible to sort of "bypass" the certificate pinning protection of Android or iOS using for example the POODLE SSL vulnerability. According to this blog Entry it is ...
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1answer
153 views

Base64 Decoding [closed]

00CDu000000000000000000000000000006e0QW00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001W00000000000000000000000000000000000000000 ...
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2answers
672 views

Why can't an n-bit hash be cracked by hashing every single n-bit plaintext?

I'm wondering why it's so hard to find collisions for cryptographic hashes. Take for example a hash function that outputs a 64 bit hash. In order to find collisions, if you feed the function every ...
2
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2answers
154 views

number of ciphertext-plaintext pairs needed in double encryption

So I know in single encryption you would simply require at least 1 pair of plaintext-ciphertext, to carry out an exhaustive key search; you continue trying different keys until one is found that ...
-1
votes
1answer
84 views

Double encryption vs single encryption

So I understand that double encryption would do no more than possibly double the time taken to break a single encryption, as the key size of double encryption would be 2k-bits and the size of single ...
0
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1answer
55 views

Padding in CBC mode

Hi I have just started learning about ciphers and padding, and just wanted to know why is padding needed in CBC mode encryption, is it to get the blocks to all be of the same n-bit length? And why is ...
1
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2answers
117 views

Protocol for secure communication over HTTP

Inspired by this hot question: Is there any reason to block HTTPS? Is there a way to setup an own server and encrypt all normal requests in the request body? So for an outside person it would look ...
1
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1answer
135 views

AES_GCM and TLS sequence number

Am I right about that AEAD encryption/decryption uses a TLS sequence number twice, first time in the nonce and a second in additional data? And why did they make the TLS 1.2 sequence number 2 times ...
6
votes
1answer
171 views

Are there any reliable estimates of the password cracking abilities of nation states?

For the purposes of evaluating a hashing algorithm against the threat of a nation state adversary, are there accepted estimates of the password cracking abilities of nation states - or is there an ...
3
votes
1answer
135 views

Is rounds in a cryptography algorithm same as iterating the algorithm?

In a cryptography algorithm such as AES or DES, does the number of rounds mean same as iterating the algorithm? Example: c= "plaintext"; for(int i=0;i<5; i++) { c = AES(c , "key"); } Where c ...
3
votes
2answers
193 views

How to 'pair' a client/server application securely?

Please forgive me if my question is a rephrasing of a common problem, but I am not sure what to search for! My use-case is a client-server program. The server runs on a user's PC and the client runs ...
9
votes
2answers
766 views

How the NSA can break trillions of encrypted Web and VPN connections

Based on Diffie-Hellman's negotiation of key exchange, why would it turn out that only a few primes are commonly used? What and who determines the prime? Would it not be safer to use a safe prime? (...
2
votes
1answer
31 views

Opening window from secure site domainA.com, to partner site domainB.com - with short TTL encrypted query string

I am looking into a proposal and need to find reasons as to why we might not perform the suggested solution. Here is the problem: www.domain-a.com is a secure website dealing with customer ...
2
votes
0answers
115 views

Deciphering “easy” ciphers without hints [closed]

I've been keen on IT Security for a long time now and I've learned a lot about networking & security. However trying a "decryption challenge" I'm lacking what I think is basic encryption/...
3
votes
1answer
150 views

LibTomCrypt weird ECC Keys

I recently started working with the LibTomCrypt Library because it claimed to be a well documented C Library to get started with Elliptic Curve Cryptography. In my first little program I created an ...
0
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1answer
196 views

Is this a good hash function?

unsigned int hash(bytearray[] msg) { unsigned int hash = 0xDECAFEBAD; for(i = 0; i < msg.length(); i++) { hash = ((hash << 4) XOR (hash >> 28)) XOR msg[i]; } return (...
3
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2answers
197 views

How to give “Forgot password” option for a password encrypted file?

I have created a utility that encrypts a file (.txt, .dox, so on...). The utility asks for a password from user at the time of file encryption. Problem Suppose a user has created 1000 encrypted ...