Symmetric cryptosystems assume two communicating entities share a pre-established secret key.

learn more… | top users | synonyms

1
vote
4answers
814 views

Initialization vector in symmetric-key encryption

Can we use symmetric-key algorithms without an initialization vector? I am making an app where both the sender and receiver share a key and there is no way to create an initialization vector for each ...
1
vote
2answers
219 views

Using IV buffer after altered inside a Rijndael CBC Encryption/Decryption process as IV for next message?

When sending a block to be decrypted or encrypted, with RijndaelCBC, we input the data to decrypt/encrypt and an IV for syncing and to prevent identical outputs for identical inputs. This question is ...
2
votes
1answer
167 views

Generating an IV for ESP 3DES-CBC

I have an application written in C, running in Linux. It uses IPsec (ESP) (manually putting the IPSec packet together) to send certain packets. The algorithm used ...
1
vote
1answer
64 views

The specification of modern, non-communicating cipher machinery [closed]

I'm looking for references, papers or guidance on a class of system which I have not seen widely discussed. Consider powerful electronic machinery which remains in the custody of communicating ...
2
votes
1answer
132 views

Camellia cipher - is it a symmetric or asymmetric cipher?

I read a wiki page about Camellia cipher and know that it is a block cipher that can use 128-bit, 192-bit or 256-bit keys. But I cant find any information about if its a symmetric cipher (uses one key ...
5
votes
2answers
448 views

why DES uses exactly 16 rounds?

Why DES uses 16 rounds why not more or less then 16. what is the significant of using 16.
2
votes
3answers
374 views

why DES encryption uses different modes like ECB,OFB?

As without using modes we can also encrypt and decrypt data then what is the need of using modes in DES?
3
votes
1answer
199 views

Is this an acceptable authenticated encryption?

After much deliberation, I've decided to use a normal Encrypt-then-MAC scheme instead of an authenticated encryption mode such as GCM as authenticated encryption primitive. This is due to the lack of ...
1
vote
1answer
259 views

Homomorphic Encryption

Homomorphic Encryption (HE) which supports any function on ciphertexts is known as Fully Homomorphic Encryption (FHE), while Partially Homomorphic Encryption (PHE) includes encryption schemes that ...
2
votes
1answer
62 views

How does the possible attack on passwords and salts mentioned in PKCS#5 v2.1 work?

From PKCS#5 v2.1, 4.1 Salt (page 6, emphasis by me), also in v2.0, RFC 2898: In password-based encryption, the party encrypting a message can gain assurance that these benefits are realized ...
0
votes
2answers
83 views

Prepend information about encryption implementation to the stored data

I want to preface this by saying i will not be using any of this code/information in a live project, this is only for learning/fun (so I welcome some speculation) I was looking at how the PHP crypt() ...
1
vote
1answer
167 views

Is symmetric key encrypted with server's public key secure

I'm trying to implement lightweight yet secure protocol for communicating two trusted parties with each other. Consider following scheme: Alice wants to establish secure two-sided channel with ...
2
votes
2answers
181 views

IV Security Clarification

After doing lots of reading on SO and other websites relating to AES cryptography, I am trying to understand the security issues surrounding IV's. There seems to be a lot of confusion and ...
2
votes
3answers
218 views

Requiring a “supervisor” key pair and a “user” key pair to decrypt multiple-recipient messages

I've been toying with some encryption scenarios recently. One of the hard ones I came across is a multi-party system. So we have Bob -- The person who sends the message (and knows it's recipients) ...
3
votes
2answers
336 views

What is the best way to store sensitive information on the client?

I am very inexperienced with cryptography and would like some advice on how to store some sensitive information on client machines. I have some information stored in a central database on my server. ...