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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44 views

length of a session key in EC?

In elliptic curve cryptography what should be the length of session key? Is there a specific metric to choose one, or are they randomly generated? I was studying one paper about defence against a ...
11
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0answers
478 views

Strength and length of Symmetric vs Asymmetric keys [duplicate]

There are many questions surrounding the differences between symmetric and asymmetric encryption keys. I think I've read them all at this point. But I'm still left wondering: Why does a "secure" ...
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1answer
192 views

AES 256 bit key to plaintext conversion? [closed]

I'm a little rusty on cryptography, but I have successfully acquired a 256 bit key that is used for encryption and I want to know if it is possible to reverse it into its corresponding plain text ...
0
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0answers
32 views

TLS fallback when only one protocol is enabled

Consider I have IE with ONLY TLS 1.2 enabled. TLS 1.0 and 1.1 are disabled. (And SSLv2,v3) I have a server that only supports TLS1.2, with 1.0 and 1.1 disabled as well. Assuming they share a ...
2
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0answers
69 views

Offering a privacy scenario with PHP mcrypt library

first of all, sorry if my question is not clear, because English is not my first language. Anyway, let-me explain the concept I'm struggling to solve as the best solution. I have some guys, and they ...
0
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1answer
56 views

How to save a web page with its certificate?

I've made a payment to an online store and they're claiming there's no order with the number that appeared in my screen, therefore they're refusing to send me the product. I still have the page opened ...
23
votes
5answers
5k views

Never spell a word the same way twice?

A long time ago I was reading about Renaissance-era ciphers and I remembered this quote: David Kahn, author of The Codebreakers, quotes Giovanni Battista Porta who published, in 1563, a famous ...
0
votes
1answer
150 views

SSO software – where is symmetric key stored?

In SSO software (Oracle E-SSO …), I heard about (primary) key encrypting user’s credentials, but I can’t read anything about how this key is managed ? When using smartcard, I can understand that ...
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votes
2answers
97 views

Will cyber security be around forever? [closed]

As time goes on, won't computers be able to automatically test for vulnerabilities to the point where they will not be prevalent any more? What I'm essentially asking is will information security be ...
1
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0answers
94 views

Problem in understanding Blakley's Secret Sharing Scheme

I need to implement Blakley's Secret Sharing Scheme. I have read below mentioned two research papers but still unable to understand how to implement it. 1. Safeguarding cryptographic keys 2. Two ...
0
votes
1answer
498 views

How does LSARPC protocol work?

I'm trying to understand how does the LSARPC protocol work internally. In particular, I would like to know how secured is it. I couldn't find anything in the internet or in different books.
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votes
2answers
577 views

Generating authentication token from PHP sessions

I have a traditional PHP site which uses sessions. I've developed a real-time app in nodejs and wish to authenticate users here based on their PHP session. The procedure would go something like this: ...
0
votes
1answer
65 views

Is it possible to perform one-way OTR MITM?

Here's something that is bugging me recently: suppose that me and my friend establish an OTR session and - as a result of that - DH key exchange is performed. My friend verifies my key, but I cannot ...
0
votes
1answer
145 views

Two-factor encryption model [closed]

Please some on help me to understand this "Are you ready for this? With the two-factor encryption model your data is protected two-fold. First, a unique key is generated, encrypted, and turned into ...
3
votes
2answers
321 views

Encrypting USB traffic: Is RSA necessary for AES session key exchange when using pre-installed secret keys?

I need a solution to encrypt USB communication between device A and device B. I was thinking about configuring each device with a secret RSA-2048 key, which would be used to exchange an AES-256 ...
1
vote
1answer
154 views

Correct auth method using oAuth 2.0?

Been trying to wrap my head around oAuth 2.0, but I'm struggling figure out the correct way to implement it for our system, as there are so many different approaches. Our specifications are: Secure ...
-2
votes
1answer
104 views

Is it really worth to spend time on Telegram Crypto Contest? [closed]

Telegram is running this crypto contents. But what I heard from some people on the web is that they designed the contest in such a way that they made it practically impossible to crack. Is it really ...
7
votes
7answers
681 views

Is it possible to make a more secure random number generator algorithm by XORing two or more less secure random number algorithms?

Is it possible to make a more secure random number generator (e.g. for cryptologic purposes) by combining two or more less secure random number generator algorithms using XOR? Here is an example of ...
6
votes
1answer
304 views

Is it considered worth it to replace OpenSSH's moduli file?

Consequences of tampered /etc/ssh/moduli describes a possible risk if the moduli file for an OpenSSH server has been tampered with. Taking the logic a step further, is there any concern with the ...
2
votes
1answer
221 views

PBKDF2 strong salt for client-side hashing

What should I use as a secure/strong salt for PBKDF2 hashing when salt is not available to use before login as it will be client-side javascript to hash user+pass with PBKDF2 ? I'm going to use ...
1
vote
1answer
75 views

PBKDF2 strong salt

I want to use a strong authentication scheme, so I decided to use PBKDF2. I'm using PBKDF2 with SHA256 algorithm, 5000 iterations and I use username (which is full email address of user) as salt. So ...
0
votes
0answers
124 views

Cryptographic Testing

Given an algorithm (say, AES), how to create/generate test vectors? I have tried using the NIST test vectors for AES and found it to be working fine with a package of "chilkat". Suppose, for a ...
0
votes
0answers
153 views

Client authentication with a collection of open source distributed servers

With a collection of open source distributed servers, all sharing every users data. How can the user authenticate with any server, without the passwords being compromised by a malicious server? ...
0
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2answers
90 views

How do certificates work in protecting against a man-in-the-middle attack? [duplicate]

As I understand it, if Alice and Bob wants to communicate securely, they must first agree on the protocols that will be used. Then they must confirm that they are indeed communicating with each other. ...
0
votes
3answers
111 views

Constant time compares when array sizes are not equal?

What is the preferred or recommended way to pursue contestant time compares when array lengths are not equal? Should we exit as early as possible? Something like: if (array1.size() != array2.size()) ...
6
votes
3answers
243 views

Any way to prove that two devices are in the same physical space, for authentication?

I need to come up with digital proof that two physical devices are in the same (approximate) location whenever that transaction occurs. This could be: A digital ID and the authenticator A consumer ...
30
votes
3answers
27k views

Now that it is 2015, what SSL/TLS cipher suites should be used in a high security HTTPS environment?

It has become quite difficult to configure an HTTPS service that maintains "the ideal transport layer". How should an HTTPS service be configured to permit some reasonable level of compatibility while ...
2
votes
1answer
440 views

Arduino to Android secure bluetooth connection

I'm using an Arduino Uno and a nRF8001 board from Adafruit to connect to an Android phone over bluetooth. I will be using it to lock and unlock a lock and I need to make sure only verified devices are ...
1
vote
3answers
192 views

Would this generated CSRF token be considered cryptographically strong?

I am working on enhancing the security of an existing web application which currently has not implemented the use of anti-CSRF tokens, so it is up to me to generate one, add the hidden fields and ...
3
votes
2answers
365 views

LUKS nuke efficiency

I am wondering about LUKS nuke patch efficiency. In fact, I think I don't really understand it. From what I know of LUKS, a passphrase is used to encrypt a random key (the master key), which is used ...
8
votes
3answers
1k views

Does the entire AES encrypted dataset have to be present to be 'cracked'?

I am implementing an AES 256 algorithm on credit cards and I am wondering if I would be strengthening or weakening the encrypted dataset if I split the dataset and persisted it in two locations. I ...
17
votes
5answers
515 views

What concrete parameters can I change to make my passphrase-protected private gpg key more secure

There are several questions which discuss the resistance of passphrase-protected private gpg keys against brute force attacks. It seems, this kind of discussion could go on forever. Rather than ...
43
votes
3answers
4k views

Is Git crowdsourcing cryptographic attacks?

A strong cryptographic hash makes collisions unlikely. Many cryptographic protocols build on that fact. But Git is using SHA-1 hashes as object identifiers. So there are a lot of already computed ...
0
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0answers
78 views

Suggestion of encrypt method for short fixed size result

I'm searching for a encrypt method that receives an int variable and outputs exactly 11 hexadecimal digits. I'm starting on a existing application, that already has a database of more than 130.000 ...
0
votes
1answer
77 views

Integrity-Based Execution

Intrusion Detection Systems (IDS) rely on binary signatures or known-bad-behavior of malware in order to detect threats. It has become very clear that this approach has limited success due to the fact ...
9
votes
4answers
4k views

Is Changing a File Type and Name an Effective Security Solution?

Is renaming folders & files and changing file types an effective solution for file security of a PC? I am an application programmer and have an extensive background in it. I have written a ...
1
vote
1answer
143 views

Calculating D-Wave's integer factorization capabilties

D-Wave has teased the ability to perform integer factorization previously, but if you jump to ~10:00 in this presentation they actually appear to outline how they can perform integer factorization ...
2
votes
2answers
203 views

Why is GPG encrypted message size not proportional to number of recipients & file size?

I have noticed that when I am using GnuPG to encrypt a file for multiple recipients, the size of the encrypted message does not seem to be directly proportional to the number of recipients. For ...
7
votes
1answer
712 views

Is there a method to get plain-text from cipher-text in HMAC SHA-1, given that the key is known?

This is technically not even an attack. We have all the resources at hand, except for the original plain-text. We have the cipher-text (to be converted back to plain-text), as well as the key. The ...
4
votes
2answers
350 views

Including and storing the order of character entry in a password as an enhanced security measure

I'm sure I will be quickly corrected if this is a stupid idea, or if it has already been tried. My question is: has this idea been tried before? If not, are there good reasons it would not work, or ...
1
vote
0answers
55 views

Public keys Quality

Is there any way to test the quality of generated keys from a public key cryptosystem? I've read about the common RSA attacks, but attacking the algorithm may not mean checking if the generated keys ...
2
votes
3answers
203 views

Are there any flaws in this two way cryptographic function?

I created a simple two way cryptographic function which allows you to encrypt a message and decrypt it with the same key. Here's how it works. Split the message into an array of 32-bit (or something ...
2
votes
3answers
134 views

how to find a cryptography scheme (either authentication or encryption) for which some formal analysis of security has not been done yet [closed]

I have a project in Cryptography where I have to discuss the provable security of any proposed scheme (encryption or authentication) which has not been discussed yet. Any pointers on how and where to ...
0
votes
3answers
396 views

How strong is a simple XOR encryption with random IV?

I'd like to implement some kind of simple (yet as strong as possible) encryption for my client-server application network traffic. Data to be encrypted can be both textual, and binary. Now I'm ...
0
votes
1answer
166 views

Can a botnet be used to effectively break encryption keys?

Can a botnet amass and coordinate enough computing power to break encryption keys that are typically considered to be secure (through brute force)? If this is the case, do we need to make our ...
-1
votes
1answer
74 views

Calculating the breakability of a given encryption method

I will soon be doing a very important project for school. The main goal of my project is to find a mathematical way to calculate the breakability of a given encryption method of ciphertext. Is there ...
1
vote
1answer
174 views

How are SHA1 and MD5 considered to not protect against collisions?

SHA1 and MD5 hash functions are considered to not protect against collisions while SHA2 is. Is it the size of the message digest that makes this or the algorithm itself? If it is based on the message ...
0
votes
1answer
115 views

Why do we encrypt ephemeral Public key in Encrypted Key Exchange

Encrypted Key Exchange can resist off-line dictionary attack Protocol : A ---> B : Ep (PK) B ---> A : Ep(Epk(K)) K is Session Key generated by B PK is an ephemeral public key ...
2
votes
1answer
2k views

How can you check if a private key and certificate match in OpenSSL with ECDSA?

I know how to do this with RSA keys (see this article: Determine if private key belongs to certificate?) however I do not know how to do this for ECDSA certificate / key pairs. With RSA keys, the ...
0
votes
1answer
1k views

AES 128bit decryption using a key longer than 16 bytes

I got a little problem regarding AES decryption. I have to decrypt some text that has been encrypted using 128bit AES / ECB with PHP mcrypt. The thing is, the key that is being used to encrypt/decrypt ...