All Questions
68
questions
1
vote
0
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41
views
In Kerberos, is the "Authentication Server" the only "Trusted Third Party"? Or is "Ticket Granting Server" also a "Trusted Third Party"? [closed]
I know that AS (Authentication Server) is a TTP (Trusted Third Party) because it generates keys for two entities (for the client and the TGS).
But what about TGS (Ticket Granting Server)? It also ...
- 51
0
votes
1
answer
71
views
Shared Key message-encryption multiple receiver communication
Say there are 5 parties. 1 is the sender, and 4 are the receivers.
The sender has a unique shared key with each receiver.
k1 - between sender and receiver1
k2 - between sender and receiver2
k3 - ...
0
votes
1
answer
639
views
Why does symmetric encryption not provide authentication and integrity? Is it only this type of encryption or cryptology in general have this issue?
Studying for Cryptology and came across a presentation regarding on "Integrity vs Authenticity" where the discussion briefly mentions how Encryption "does not provide integrity or ...
- 65
0
votes
1
answer
75
views
Safe implicit value validation: $H_k(k \oplus m) \sim H_k(m)$?
$H_k$ is a cryptographic hash function that's keyed using a section of key material $k$ (for whatever definition of "keyed" that's appropriate for the given hash function $H$).
Are the ...
- 814
0
votes
1
answer
110
views
Derrive a new key from Trusted Third Party (e.g. Kerberos) session key
Kerberos (and I assume other Trusted Third Party protocols) use (hash) an existing shared secret key to create a session key used for authentication. I read that this authentication secret key can ...
- 3
1
vote
0
answers
152
views
Issue with AWS Encryption SDK for JavaScript in Browser: 'Buffer is not defined' [closed]
I'm trying to implement AWS Encryption SDK for JavaScript in a browser environment within a React application. When I attempt to construct an instance of the encryption client using buildClient ...
1
vote
0
answers
50
views
Can new decryption keys be issued without modifying the encrypted contents? [closed]
I'm curious if there's an encryption scheme where content may be encrypted to a public key where the associated private key can generate new decryption keys for the same content. The goal is to ...
- 11
2
votes
2
answers
199
views
How to destroy a randomly generated key after using it?
for example, I have an encryption program like this:
Input: a message, M; my public key Kpub
Step 1: randomly generate a ...
- 99
3
votes
3
answers
1k
views
How to interpret my professor's statement about "seed" and "symmetric-key encryption"?
In the cryptography course, the professor said that:
these days for symmetric key encryption, instead of sending out the key, Alice sends the seed to Bob, and then based on that Bob can get the key.
...
- 43
3
votes
1
answer
374
views
Is PRF XORed with its key still a PRF? (always)
$\forall k \in \{0,1\}^n,m \in \mathbb{M},F_k(m)$ is defined as follows: $F_k(m) = F'_k(m) \oplus k$. It is known that $F'_k$ is a PRF. Note: 𝕄 is the message space and it's assumed that the key $k$ ...
- 73
0
votes
0
answers
29
views
How does a forward search attack work? [duplicate]
I just came across this term “forward search attack” while reading about Interchange key and Session key. The book mentioned that using session key helps to prevent attacks such as forward search ...
0
votes
0
answers
171
views
Key storage management of session keys and long term keys
In key management, one of the topics is key storage, I want to know where and how these keys(long-term and short-term) are stored?
For example I read that android password apps use KeyStore api to ...
- 1
0
votes
1
answer
79
views
Symmetric Exchange Key Sharing
Question:
Suppose that there are 10000 = 10^4 banks and 10 payment card organisations (PCOs).
How many secret keys will be needed if each PCO shares a unique secret key with each bank?
How many extra ...
- 1
1
vote
0
answers
52
views
Help needed for IBM KCV
I found old key letters used in EFT HSMs with TDES keys, parted in two halfs. The check value printed on this letters is called IBM CV and doubled IBM CV.
My newer HSM does not support this kind of ...
- 11
0
votes
1
answer
256
views
Calculating symmetric key bit strength
16 byte key where each byte is in range 0-255, generated using cryptograhic PRNG will be believed to have 128 bit strength.
What would be a bit strength of a key generated using same quality PRNG, ...
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