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 ...

learn more… | top users | synonyms

7
votes
4answers
275 views

Decentralised password recovery

Are there good/established techniques for password/key recovery in situations without a centralised service? (Anything goes, but I'd prefer solutions that distribute the recovery information across ...
0
votes
0answers
11 views

Is AES-GCM length extension attack possible using authenticated decryption?

I am looking to encrypt a piece of data using AES-GCM with a full 16-byte GCM Tag and send it over the network using UDP. Is it safe to assume using the AEAD nature of AES-GCM that performing ...
211
votes
7answers
154k views

RSA vs. DSA for SSH authentication keys

When generating SSH authentication keys on a Unix/Linux system with ssh-keygen, you're given the choice of creating a RSA or DSA key pair (using -t type). What is the difference between RSA and DSA ...
0
votes
0answers
72 views

Is Tox really secure? [on hold]

There is a new Skype-killer application called Tox. They said that it's open source and that it protects its users against governments and other adversaries that try to collect your information. But ...
8
votes
2answers
123 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 ...
0
votes
1answer
31 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 ...
1
vote
0answers
10 views

How were shift amount constants in MD5 found? [migrated]

The md5 specification gives a series of 4 rounds to execute over a 16-word block. Each round has a repeating sequence of 4 shift amounts (s in [abcd k s i]) : 7, 12, 17 and 22 for the round 1 5, 9, ...
-8
votes
0answers
94 views

If https is so good (as to completely replace http), why is DJB not using it? [on hold]

D. J. Bernstein, http://cr.yp.to/djb.html, @hashbreaker, is famously known for his crypto and hashbreaking abilities. Outside of the theoretical research that he is engaged in as a professor, his ...
280
votes
4answers
83k views

Do any security experts recommend bcrypt for password storage?

On the surface bcrypt, an 11 year old security algorithm designed for hashing passwords by Niels Provos and David Mazieres, which is based on the initialization function used in the NIST approved ...
-1
votes
0answers
9 views

Java Keystore best practice for large scale application [on hold]

I'm new to JCE/cryptography in general but I'm working on demo where we are going to create a public/private key combination for each users of the site. All the examples I have seen so far stores ...
2
votes
1answer
89 views

NaCL: Encrypt file to multiple recipients

I am trying to understand the Networking And Cryptography Library (NaCL). Consider i have a file that i want to send to multiple recipients. PGP or S/MIME supports multiple recipients by encrypting ...
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 ...
2
votes
2answers
81 views

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

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 ...
-2
votes
0answers
29 views

KakaoTalk message encryption [closed]

I am trying to write a tool to decode the KakaoTalk chat application and the messages are encrypted with this pretty bizarre looking base64 'Lx7ZczQJ/sdOAw8DdFcauw==', That might possibly be a base64 ...
0
votes
1answer
104 views

Asymmetric vs Symmetric Encryption Benchmarks

I have found these benchmarks in Crypto++'s site. http://www.cryptopp.com/benchmarks.html But I am, quite honestly, not entirely sure how to interpret them. I am really looking for a set of ...
58
votes
8answers
122k views

How to determine what type of encoding/encryption has been used?

Is there a way to find what type of encryption/encoding is being used? For example, I am testing a web application which stores the password in the database in an encrypted format ...
1
vote
1answer
63 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 ...
0
votes
1answer
760 views

What is the deal with Valicert SSL root certificates?

Does anyone know what the status of the "Valicert Class 2 Validation Authority" root certificate is or what's going on with Valicert in general? I've heard that that cert has been deprecated, no ...
80
votes
6answers
26k views

Password Hashing add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
292
votes
11answers
52k views

How to securely hash passwords?

If I hash passwords before storing them in my database, is that sufficient to prevent them being recovered by anyone? I should point out that this relates only to retrieval directly from the ...
0
votes
0answers
125 views

Gladman's file encryption library = AES in counter mode with HMAC-SHA1 authentication?

I would like to use Gladman's algorithm to create AES encrypted data in JavaScript. I use the Crypto-JS library, but its performance is horrible. PBKDF2 is terribly slow, so I switched to another ...
0
votes
0answers
581 views

OpenSSL: Bad Record MAC on TLS Heart Beat

I am trying to see the heartbleed bug in action with my OpenSSL server application. My server uses the OpenSSL library - openssl-1.0.1b I successfully connect with s_client (openssl-1.0.1b) to my ...
0
votes
0answers
30 views

DTLS CertificateVerify doubt

In DTLS 1.2 RFC 6347, section 4.2.6: CertificateVerify and Finished messages have the same format as in TLS. Hash calculations include entire handshake messages, including DTLS-specific fields: ...
0
votes
0answers
127 views

RSA 4096 key size difference - “sig” and “sig 3”

Whenever I generate a new 4096 RSA key in my GPG program and export the public key to a text file, I get a text file containing a total of around 52 lines (it varies, one of them is 53 lines). ...
6
votes
3answers
688 views

How can I prove that I wrote a certain blog post?

I would like to be able to prove that I wrote the article that resides at a given URL on someone else's blog. Is there a way that I can do this with public key cryptography? I know a bit about the ...
2
votes
1answer
258 views

Requiring 2 keys to access a content

I need to use an external service that can only be accessed by password. I don't like the idea of storing the plaintext password on the server, but AFAIK there's not much I can do. Considering this ...
24
votes
6answers
25k views

Asymmetric vs Symmetric Encryption

I am currently taking a principles of information security class. While talking about different encryption methods a large number of my classmates seem to believe that Asymmetric Encryption is better ...
39
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 ...
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 ...
0
votes
0answers
35 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
55 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 ...
29
votes
5answers
51k views
2
votes
2answers
66 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 ...
0
votes
1answer
86 views

Publicly Available API + Sensitive ID/Key Transmission Over HTTP

I've run into a predicament... I'm developing a mobile application that utilizes a server for various things. One portion is that it stores an id/key pair related to accessing and processing ...
4
votes
2answers
295 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 ...
7
votes
1answer
473 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 ...
2
votes
3answers
134 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 ...
1
vote
0answers
47 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
0answers
15 views

How to compare security parameters of different schemes (Sign-Encrypt, Encrypt-Sign, etc)? [migrated]

How can one compare the security parameters (confidentiality, integrity, non repudiation, etc.) for different schemes (Sign-Encrypt, Encrypt-Sign, Sign-Encrypt-Sign, Encrypt-Sign-Encrypt)? Are there ...
0
votes
1answer
146 views

How to secure my REST API once user authenticates with Google on mobile client?

In my application, I build REST APIs so that user can interact with my application server. Since I do not want to maintain User/Passwords, my iOS app authenticates client using Google. This all ...
0
votes
4answers
190 views

How safe is it to use older/unknown Encryption methods for plaintext?

When mailing or chatting with people, it had crossed my mind, what if, for simple communication, someone would use an older encryption method (i.e., ENIGMA), to encrypt their message? Would because ...
1
vote
2answers
66 views

Using OAuth 2.0 without token storage

I am building a system for a product which requires Authentication and Authorization. Naturally I have chosen using OAuth 2.0 as it is a commonly used protocol and has proven to be useful. I am ...
21
votes
4answers
3k views

How would you store a 4 digit pin code securely in the database?

I'm familiar with password hashing, using salts, bcrypt etc. But it doesn't seem like this would work to store a 4 digit pin code since the attacker could try all 10,000 combinations quite quickly. ...
0
votes
3answers
179 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 ...
1
vote
1answer
63 views

How to store derby database encryption key in HSM?

The Derby Database supports encryption with a key or password. Traditionally this key is stored in the file systems, now I am looking to store and protect this key in the HSM instead, but I couldn't ...
3
votes
2answers
240 views

Continued Use of Kerberos

I posted this question over on Crypto.SE, but didn't get any takers and thought it might be more suited for this site as it were, so I'm cross posting it here. I was recently looking through the Mac ...
9
votes
3answers
2k views

Suitable cipher for SMS encryption

I would like to create application for encrypting SMS messages. After long enough discussions I decided to use symmetric encryption, since handling public/private keys issue is too difficult for most ...
0
votes
1answer
65 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
43 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 ...
4
votes
4answers
465 views

How widely deployed is TLS with cipher ECDHE?

Microsoft deployed a patch for Windows 2012 R2 and Windows 8.1 that adds the following ciphers. Cipher suite Exchange Encryption Hash TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH ...