5
votes
3answers
312 views

Leak-proof protocol: is such a thing possible?

Is it possible to design a protocol that by itself guarantees that a malicious implementation cannot leak secret data without breaking the protocol? Setting: Alice and Bob have a pre-shared secret ...
6
votes
2answers
182 views

Encrypting or HMACing password digests

Assuming I'm using bcrypt to digest passwords, is any additional security gained by either encrypting or HMACing the resulting digests? By requiring a key to compare password hashes, I would expect ...
2
votes
2answers
47 views

ECDH anonymous key exchange to avoid PKI

I want to use TLS to encrypt the communication between peers in a P2P network. Each peer has a well known 256bit peer identifier (the public key of a 256bit elliptic curve keypair). Both peers need ...
0
votes
2answers
60 views

Public key Issue - same key pair as existing one?

My question is a bit naive, but what if someone generates the same RSA key pair as someone else? This person would have the same private key and so would be able to decrypt messages not intended to ...
4
votes
1answer
191 views

AES-CTR with ephemeral keys vs IV

Let's say that we have a key exchange of some sort, which leaves A and B sharing the long-term secret $S$. Then, A and B want to use AES-CTR for the communication, which leaves us with several ...
3
votes
1answer
63 views

Deterministic Rand function for Winternitz One Time Signatures

Suppose you are implementing a Generalized Merkle Signature Scheme, using the Winternitz One-Time Signature Scheme for the node signatures. Furthermore, suppose the implementation is to be stateless ...
3
votes
1answer
85 views

Measure ECC key size

I have implemented a ECC key generation scheme successfully. Now I need to find ECC key sizes of each generating key pairs. I assumed that ECC key size is the size of the ECC private Key. So I would ...
3
votes
1answer
101 views

Which concrete applications benefit from Oblivious RAM constructions?

The main motivation for Oblivious RAM (ORAM) is that, for instance, in the "cloud" setting a client outsources his data to a server in the form of encrypted blocks. Later on, he wants to perform read ...
-1
votes
1answer
132 views

What does it mean that a protocol realizes “strong mutual authentication”?

What does it mean that a protocol realizes "strong mutual authentication"? And What does it mean that a protocol realizes "weak mutual authentication"? Can you define them formally ? I have found a ...
-1
votes
1answer
45 views

How is a Yubikey static password derived from the AES key?

When I configure a Yubikey slot as static, it's not documented or obvious how the static password yielded by a press relates to the AES key I set. For example: ...
-1
votes
1answer
94 views

Attacking both authenticity and secrecy in authenticated encryption modes

looks like NIST only approved GCM mode for authenticated encryption and other modes don't have any approval or a good implementation available. Is that possible a weakness in $GHASH$ compromise ...
0
votes
0answers
41 views

What is the default type of salt for encryptions in Heimdal Kerberos?

I am trying to figure out what the salting mechanisms are for various kinds of encryptions in Heimdal Kerberos. In section "4.11 Encryption types and salting" of the Heimdal Kerberos documentation it ...
0
votes
0answers
149 views

How to safely sign a 6 characters String?

I have to decide, whether a document, which I am given, was correctly signed by a private key. my Ideas is to sign the document id using RSA with the private key and to print the following onto the ...
-1
votes
0answers
67 views

A problem about zero knowledge proofs

$En()$ is a certain encryption function, $G$ is a cyclic group with order $q$ (a prime), $g,h$ are two generators of $G$. $\lambda_1,\lambda_2 \in Z_q^*$, $\mu$ has the relation $\mathcal{R} ...
-2
votes
0answers
23 views

Would it be possible to crack the key used for params given DES

I am working on a product that will link back to another product. The problem is the GET params on the target product are encrypted using DES (I believe) so the params look like... ...

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