All Questions
Tagged with symmetric authentication
20
questions
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639
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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
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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
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46
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How LastPass decrypts database on web browser?
According to video from Dr. Pound, password managers (LastPass in particular) holds encrypted image of your data on their servers and then with master password you authenticate to get encrypted image ...
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1
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75
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How to ensure files on client computer haven't been tampered with by client?
I'm designing a program that clients can download to the computer. This program needs to sync with my online server on a regular basis to confirm that the client's Activation Code hasnt expired and ...
- 3
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46
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Authentication by Presenting the Symmetric Key over an Encrypted Channel
I have devices which need to communicate with a server over a mutually authenticated and encrypted channel. Authenticating the server is relatively easy, since I can embed the CA certificate in the ...
- 117
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2
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692
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Designing a simple challenge-response symmetric mutual authentication protocol
I am designing a protocol that 2 devices will use to mutually authenticate over an unreliable, unsecure channel. The system must be fast and low-power, so symmetric cryptography is a requirement. I ...
- 101
1
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1
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175
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Are the signcryption and the authenticated encryption same?
The signcryption and the authenticated encryption are both the combine of encryption and authentication with three natural composition (i.e., EtS, StE, E&S). I am not sure that if they are the ...
- 1,622
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58
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Lightweight provably secure design [closed]
Is it possible to device lightweight (i.e. without asymmetric crypto and PKI; and without third party Trent) provably secure (in the exact security sense) scheme? Were there any attempts? Is it ...
- 609
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4
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2k
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Why do one-time pads not provide message authentication?
It is often said that one-time pads do not provide message authentication. But, if you and I have a one-time symmetric key, and I send you a message, and it is not complete gibberish, is that itself ...
- 25
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86
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Authenticating without sending password to the server, and store data encrypted with password derived key on server
I am trying to think of a scheme that would allow a user to authenticate to a server, whithout sending the password to the server, and to also derive a symetric key on the client (that also never gets ...
- 101
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60
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How can a node establish pairwise shared key with other nodes using its own polynomial share together with other's public values?
A server has a symmetric bivariate polynomial $ F(x, y) = \sum_{{i,j}=0}^{t-1}a_{i,j}x^iy^j$ $\in GF(p)[X, Y] $ of degree $t-1$. For simpliciy, $ F(x, y) = a_{0,0}+a_{1,0} x+a_{0,1}y+ a_{1,1}xy$ mod ...
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1
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1
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324
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Why is this authentication protocol with a nonce and tree parties not secure?
Why is the following authentication service not secure?
C⟶S: $I_C$
S⟶C: $N$
C⟶S: $E(K_{C,A}, N)$
S⟶A: $E(K_{S,A}, \{I_C, E(K_{C,A}, N)\})$
A⟶S: $E(K_{S,A}, N)$
where:
C = client
S = server
A = ...
- 13
1
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1
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237
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Is symmetric encryption with a key containing the userId passes as authentication?
The scenario:
There is a web application where ownership check is time expensive so during the development all users were able to access all other user's objects (let's say apples) by changing the ...
- 113
1
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2
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1k
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Is the security of an HMAC equally important as the security of the cipher itself?
I'm a little unclear on how hash based MAC works... So I would like to know, is the security of your hash function as important as the security of the overall cipher? Basically, if you can crack the ...
- 197
3
votes
1
answer
581
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(Lightweight) Multicast one-way Authentication
Problem:
I'm thinking about a lightweight solution to provide source authentication (only one source) to multiple receivers (multicast message).
Context:
Taking the problem to ground, we can think of ...
- 31