0
votes
2answers
82 views

How to combine a key and a password in practice

Alice wants to encrypt her data. She is not comfortable with using only a password. While she prefers to use a properly random crypto key, she isn't confident she can protect the key file from theft ...
0
votes
2answers
67 views

How to generate a superkey to decrypt strings

I'm working on an application where users have a key or password generated by me that is used to encrypt a string. Each user has their personal key, and no user should be able to decrypt another ...
0
votes
3answers
72 views

What does the pgp public key length depend on?

What does the pgp public key length depend on? Does a long private key result in a long public key? The longer public key the better; or is it even the private key the crucial factor?
0
votes
2answers
89 views

How to compare encrypted private keys?

Is it possible to compare encrypted private keys if you do not have the passphrase? E.g.: openssl genrsa -out unencryptedprivkey.pem 2048 openssl rsa -in unencryptedprivkey.pem -aes128 -out ...
0
votes
1answer
81 views

Which default encryption does openSSL use?

If I create a private key via: openssl req -x509 -newkey rsa:2048 -out cert.crt then openssl writes the private key to the file privkey.pem and if you do not provide the "-nodes" command it will ...
0
votes
1answer
94 views

Multi user symmetric key encryption

I realize SIMILAR questions have been asked before but I'm looking for certain specifics I can't seem to find elsewhere. The following question closely resembles mine but falls short for me on ...
0
votes
1answer
162 views

What is the point to the IPEK in DUKPT?

I'm trying to understand the DUKPT (Derived Unique Key Per Transaction) system used for PIN devices, but I'm getting hung up on the IPEK. This blog post has an image where the sequence is: BDK ...
2
votes
1answer
438 views

Storing encryption keys on a server using Node.js and MySQL

I am writing a web backend/api for an iOS application using Node.js and MySQL. In my database I have a table for posts. I would like the posts content to be encrypted. Let's say I'm using this AES for ...
6
votes
4answers
265 views

Relationship of password strength and key strength

I have just started educating myself about cryptography, and while it is mostly making sense, a few things are still eluding me. One being: In systems that take a user's pass-word/-phrase in order to ...
1
vote
3answers
321 views

How does encryption/decryption work when one generate random key?

I am new to this and want to ask a basic question. Suppose I used my password (say "ABC123") to generate a key using the PBKDF2 algorithm (or any such algorithm). For encrypting a file I'll input my ...
0
votes
1answer
79 views

Encryption key generation performance

A question for cryptography experts. Imagine we have a conceptual Notes.app: There are notes (title|content) stored as AES-256 encrypted strings Application has to present a list of all notes ...
7
votes
3answers
259 views

How can I allow acces to encrypted data if only 2 out of 3 users provide a secret?

I want to encrypt data, but make sure that no single user can decrypt the data. Further, it is important not to require ALL users to be present to decrypt. This will allow for some flexibility and ...
-2
votes
2answers
119 views

Is this a possible solution to the impractical requirements of using a One Time Pad?

For the sake of example, lets say there are two people named, Bob, and Jim. The Problem Bob wants to send Jim a long secret message, and he decides to use a OTP to encrypt his message. Both Bob and ...
2
votes
1answer
366 views

AES key management

I am encrypting a secret in a db field. I am encrypting using AES with a 256-bit key and a random IV per encryption. They AES key is hard coded in the code. Each IV is stored in clear in another ...
2
votes
2answers
914 views

Explain real world symmetric key encryption

I'm new to cryptography. While reading about symmetric key encryption, it was mentioned that it requires secret key exchange so that 2 parties can decrypt the ciphertext. Now, using some encryption ...
7
votes
1answer
382 views

HKDF and key stretching

I thought that all key derivation functions would do a key stretching phase, by iterating some kind of process. But I can't see that process in HKDF. HKDF doesn't do key strengthening? If I have a ...
11
votes
3answers
384 views

Can I use the same password both for SRP and for client-side encryption?

Suppose a less-than-trusted server is used to store users' confidential data (encrypted at the client side), and both tasks - authentication and encryption/decryption - should be doable with a single ...
3
votes
0answers
487 views

MPPE-Send and Receive key derivation from MS-CHAPv2

I am trying to get the MS-MPPE-Send-key and MS-MPPE-Recv-key from the MS-CHAPv2 challenge material. I am able to follow the RFCs 2548 3078 and 3079 to the step of getting the GetNewKeyFromSHA() it is ...
3
votes
4answers
493 views

Is it safe to have the salt equal to IV?

If I'm using AES-256 CBC to encrypt, getting the 32 byte key using multiple iterations of the PBKDF2 function with a 16 byte salt, is it safe for me to let IV be equal to the salt? (Edit: The salt is ...
3
votes
2answers
226 views

Is a random keyfile more secure than a derived key?

I'm devising an encryption layer for some proprietary cloud storage API. Basically this should act as a transparent adapter that encrypts whole binary blobs (files) on upload and decrypts them on ...
6
votes
3answers
292 views

How much added security do I really get with a longer key size?

Imagine I have a cipher which supports keys of 128, 192 or 256 bits. Suppose that there are no vulnerabilities in the cipher regardless of key length. I'm going to use it to encrypt something, and ...
4
votes
3answers
247 views

Security in wireless ad hoc sensor network (without physical access)

I want to know without taking physical access, what are the methods that can steal the data in a node. When talking about eavesdropping, how can an attacker sniff the packets? Do they need to listen ...
0
votes
1answer
250 views

How key_derivation and key_verification functions are implemented of a 7-zip archive's encryption mechanism?

I am curious about how password recovery works for password protected files. And I want to know the exact flow of the 7-zip encryption mechanism :) !! 7-zip uses the AES-256 encryption algorithm in ...
2
votes
1answer
3k views

Is your PGP passphrase used to decrypt an encrypted private key, or needed in conjunction with the private key to decrypt the message?

If the former, then if the private key can be used to digitally sign messages, why doesn't your client offer to encrypt this highly sensitive piece of data? If the latter, then if someone had access ...
2
votes
1answer
2k views

Convert RSA public key to the right format

I need to send a public key to my bank. I'm using CoreFTP which allows the generation of keys using RSA. It says that it generates "OpenSSH compatible certificates [sic]" when you press the generate ...
9
votes
3answers
7k views

What is the DUKPT Key Derivation Function?

I'm tasked with decrypting ciphertext acquired from an encrypted card reader. The card reader utilizes DUKPT(derived unique key per transaction) scheme and 3DES encryption. I don't have a problem with ...
2
votes
3answers
624 views

What is the recomended algorithm to create a key from a password?

In my new secret document encryption utility, the key for symmetric encryption = the hash of a random salt and a user provided password. It is necessary to have a slow hash function in order to ...
13
votes
4answers
5k views

What are you doing when you move your mouse randomly during a truecrypt volume creation?

Is that called a 'round' every time you move your mouse when creating a new volume? I'm talking about the screen with the random numbers during the volume creation process. What is the purpose of ...
6
votes
1answer
977 views

Select a TripleDES key so that it effectively behaves as regular DES

I'm working with a smartcard (DESFire) that supports both TripleDES and DES. In the specs it is stated that both modes of operation use 16 bytes keys. When the first 8 bytes in the key are identical ...
2
votes
3answers
2k views

RSA 4096 with AES 256 Encryption Process Using PyCrypto

I have the following process for encrypting and decrypting data in a python script using the PyCrypto module: Encryption - Server A AES 256 shared key is generated Associated IV is generated Data ...
9
votes
3answers
1k views

Is TDEA (TripleDES) invulnerable to the weak keys of DES?

The key space of DES includes some keys that are weak, which results in a ciphertext that is extra vulnerable to cryptanalysis. Is TDEA (also known as TripleDES) invulnerable to those weak keys? Or, ...
2
votes
1answer
1k views

RSA Key Pair generation with Javascript

I need to generate a RSA key pair with Javascript. This key pair will be used for encrypting a one time blob of data (20-100kb), then discarded. This data can be reduced to a couple of hundred kb or ...
2
votes
4answers
462 views

Hash/Digest of string; multiple clients and reverse lookup must be impossible

Ok so i need a technique (could be a system or just an algorithm) to generate a hash/digest of a string on a client app without me (admin of a server app) being able to determine what the original ...
4
votes
1answer
382 views

Asynchonous Linear Feedback Shift Register : test vectors

Well I've been working on coding LFSR structures for my research projects. Being able to find sources on the subject, I've been able to test a single LFSR with different initialisation and TAP ...