2
votes
1answer
83 views

Proof of shared secret through key derivation

Alice gives a random key $K$ (e.g. 32 bytes long) to Bob through a secure channel. Bob want to prove to Alice through an unsecured channel that he knows the key. Is it secure for Bob to send ...
3
votes
1answer
199 views

What's the most secure way to derive a key from a password repeatably?

I'm trying to write a cloud storage application where everything the user uploads is unreadable by the server, encrypted client-side before being sent. Currently, the flow looks like this: User ...
4
votes
1answer
130 views

Does EAX use the same keys for encryption and authentication?

I am actually checking use of EAX AEAD mode, and following EAX spec review (scheme definition for my part), my question is: what about the derivation of the authentication and encryption keys? In the ...
0
votes
1answer
167 views

Scrypt as a KDF with one-time high-entropy input

I'm looking at using Scrypt as a KDF. Assume the following: the input will always be high-entropy random bytes generated by a CSPRNG the length of the input can vary from between 8 to 32 bytes the ...
0
votes
1answer
181 views

brute force attack on KDF vs KEY

if we believe 256bit keys are secure in AES against any brute force attack, is that possible we use a KDF (convert user's weak entered password in truecrypt into a fixed AES key) with too much round ...
3
votes
2answers
375 views

Reason(s) for using a KDF for encryption keys

Assuming I already have a 256-key (32 char password) for AES encryption, comprised of random alpha-numeric characters and punctuation (95 possible ascii chars), generated by a decent PRNG, is there ...
1
vote
3answers
195 views

Deterministic key generation

In a situation where it is required to generate n number of keys deterministically from a single piece of seed information can we assume that b breached number of keys, no matter what the quantity ...
1
vote
1answer
100 views

On the fly key generation for cloud storage objects

Cryptographic key management involves storing and managing encryption decryption keys , certificates , signatures etc . If the requirement is just to store and manage object specific keys ( say ...
2
votes
1answer
175 views

Is it OK to use a data-encryption key for key wrapping, too?

Our industry (area of cheap networked devices) has a standard that defines the usage of keys for both authentication and encryption using EAX mode of AES. This standard does not define key management, ...
6
votes
4answers
785 views

Creating an encryption key from several other keys and using hash functions

I want to combine two or more keys to create a single encryption key that relies on all of them. What is the proper method for doing that? Simple XOR? Using hash functions? Something else? I ...
3
votes
3answers
218 views

Derived Shared Key vs Distinct Keys?

I've seen a lot of 2-party applications that derive a shared key from distinct keys created by each party. Why is this technique employed? Would it not be better to use those two distinct keys for ...
6
votes
2answers
1k views

How key materials are generated in SSL V3 from master secret

The generation of key materials is given by ...
7
votes
2answers
364 views

Key Length & Hashing

I need to use a hash function to generate a 128-bit key for a symmetric cipher. The specific cipher is from the eStream portofolio, called Rabbit. I am using the SRP protocol for authentication (a ...
10
votes
5answers
766 views

Why does PBKDF2 xor the iterations of the hash function together?

The definition of PBKDF2 states that I obtain a derived key* by calling a pseudorandom function a bunch of times recursively: ...