0
votes
0answers
4 views
0
votes
0answers
3 views

HMAC vs RSA speed

To my understanding one of the main advantages HMAC has over RSA is that HMAC is faster to compute. My question is: How much faster? Say you are signing a SHA-1 hash function 1000 times a day. How ...
0
votes
0answers
6 views

Signing a SHA-1 256 hash

What are things to consider when choosing between RSA and HMAC for signing a SHA-1 256 bit hash string multiple times. What are the advantages/disadvantages to RSA and HMAC in this case? Thanks in ...
1
vote
2answers
5 views

PRG - understanding the definition

Say $G$ is a $PRG$ that expands its input by a single bit, so we define: $$G'(x_1||x_2)=G(x_1)||G(x_2)$$ The exercise states to prove that $G'$ is also a PRG. Now here is my confusion. $PRGs$ are ...
0
votes
0answers
6 views

Comparing computation complexity of generic protocol with operation specific one

Assume we have a cryptographic protocol for secure multi-party computation that supports generic computation. Let assume the "protocol 1" uses fully homomorphic encryption (FHE) and the overall ...
0
votes
0answers
24 views

Random Bytes in TLS Handshake

During the TLS handshake, there are random bytes sent from the server to the client and random bytes sent from the client to the server. Since these bytes are sent in clear text, what is the ...
-2
votes
0answers
15 views

What do you think of Wire.com crypto? [on hold]

I'm curious to know how the crypto community feels about Wire? And how it might compare to Signal crypto! https://wire.com/ https://github.com/wireapp
1
vote
0answers
30 views

Algorithms to test vs. generate primes

What would be the value in having a true prime number generator algorithm instead of a prime number test algorithm? Also, if such a thing existed, what would be the impact on not only cryptography?
3
votes
0answers
11 views

Bitcoin multi-sign and the amount of storage it required [migrated]

I read this paper (Threshold-optimal DSA/ECDSA signatures and an application to Bitcoin wallet security), the authors said that in the optimal threshold signature that they propose players requires ...
2
votes
2answers
31 views

Why k-lists generalized birthday problem when $k=2$ is classical birthday problem?

David Wagner in his article A Generalized Birthday Problem in CRYPTO 2002 says that in k-dimensional (also k-lists) generalization of birthday problem (GBP), when $k=2$ "this is just the extremely ...
0
votes
1answer
22 views

ElGamal recovering messages

If you use the same ephemeral key in Elgamal, someone can read the future messages. I have two ciphertexts $y_1=62$ and $y_2=4$. The difference between two plaintexts is $x_1-x_2=138$ how do I get $...
0
votes
0answers
7 views

what is multi authority based weighted attribute based encryption ?? is this the current technique deployed in cloud?

As i'm interested in cloud computing domain, i have just got to see that MA-WABE is used as a cryptographic technique in cloud. can anyone brief about this technique?.if any algorithms present which ...
1
vote
0answers
11 views

Weakly Sublinear Compact FE from Succinct FE and XiO

I'm confused about a problem these days and I decided to seek an answer here. The question is about the section 4.1 of the paper LPST16. Let me recall the weakly sublinear compact FE scheme $\textrm{...
0
votes
1answer
17 views

How to show that any 2-round key-exchange protocol satisfying a given definition can be converted into a public-key encryption scheme?

How to show that any 2-round key-exchange protocol satisfying a given definition can be converted into a public-key encryption scheme that is CPA-secure? The given definition is as followed: ...
0
votes
1answer
19 views

Message Expansion / Encryption Blowup Factor / Ciphertext Expansion of ECC

In order to complete the following table with asymptotic times and message expansions, $\quad \quad \quad \quad \quad \quad \quad \quad \quad$ RSA $\quad$ McEliece $\quad$ ECC Encryption Speed $\...
2
votes
2answers
35 views

When, where, and how to use HMAC

This question may seem like a duplicate of some others, namely this one, but even though that question asked when and how to use HMAC, the answers only addressed what HMAC was and why/how it worked. ...
0
votes
1answer
30 views

Questions regarding parallel AES CTR with merkle trees

I'm planning to implement a parallelizable variant of AES to end-to-end-encrypt files in a web application. As a mode of operation I'm most likely gonna use CTR mode with a 64 bit IV and 64 bit ...
2
votes
1answer
32 views

Security model scalar multiplication in NaCl

I'm having trouble understanding what the “security model” for “scalar multiplication” in NaCl is. Security model crypto_scalarmult is designed to be ...
0
votes
0answers
18 views

XOF/derivation as OTP

Probably a stupid question but I haven't seen it asked before... What would be wrong with expanding a key to the length of a given plaintext (using Shake or scrypt) and using that as a OTP on the ...
1
vote
1answer
17 views

Finding Linear Redundancy by counting the number of distinct frequency distributions of absolute walsh transform

I am writing a program to find linear redundancy in 4x4 s boxes. Is the number of distinct frequency distributions of absolute walsh transform a direct measure of linear redundancy in s boxes? byte[] ...
2
votes
0answers
29 views

FIPS 186-4 seems to have an excessively complex q generation

So in DSA you have two primes - p and q. q is N bits long (let's assume 160 bits) and p is L bits long (let's assume 1024 bits). Here's what FIPS 186-4 says about generating the q parameter for DSA: ...
0
votes
2answers
30 views

The length of the shortest vector in Lattice

In Micciancio and Regev's paper "Lattice-based Cryptography",the length of the shortest vector is at least $\min\{q, 2^{2\cdot\sqrt{(n\cdot \log{q}\cdot\log{\delta}})}\}$ . I want to ask why the paper ...
-1
votes
1answer
17 views

Store and share data on intranet website

I'm developing an intranet for a company where admins are sharing a huge excel file containing all the necessary password, on the common TSE. I've managed making them encrypt it with a common password ...
2
votes
1answer
26 views

Proof that LFSR (with XOR feedback and nonzero seed) will never hit state of all 0s

Does anyone know a good proof that a LFSR (with XOR feedback and seeded with non-zero starting state) will never enter zero state? It is obvious that a zero state will always get stuck in a zero ...
8
votes
1answer
781 views

What exactly is a “garbled circuit”?

There are plenty of questions here about the details and how-to's of "garbled circuits", but I have not seen anything that defines what garbled circuits are. What exactly is a garbled circuit? What ...
-1
votes
0answers
36 views

How can I find all points on an elliptic curve?

I have an elliptic curve $$y^2=x^3 + 8 \times x + 6 \mod 13$$ How do I find all the points on this EC? Also, could you give me more examples?
2
votes
1answer
31 views

Client side encryption / hashing of “person ID's” with password?

What we're looking for A solution where data is stored and retrieved (!) from a server using a person ID that can only be known at the client (form of ...
0
votes
1answer
35 views

IND-CCA Security of a encryption scheme which is combination of two schemes

I have two public key encryption scheme $\Pi_0$ and $\Pi_1$ and one of them is IND-CCA secure, another one is IND-CPA secure. Let $\Pi$ be a public key encryption scheme, which is a combination of $\...
0
votes
0answers
17 views

Decoding base64 with key [on hold]

I'm working on a program that scrapes video URLs from a website. The URLs seem to be coded in base64. Here's an example: ...
0
votes
1answer
21 views

Is there a TLS extension for generating unique IVs for AES GCM?

Since reusing IVs is death for AES GCM, it seems like using the fixed IV in the TLS connection state is a phenomenally bad idea. It wouldn't even seem to be a good idea to use the salt + counter ...
2
votes
1answer
17 views

Message expansion in NTRU: why is it $\log_p(q)$-to-$1$?

Suppose that we are working with the original version of NTRU with parameters $(N,p,q,k,d_f,d_g,d_\phi)$. In this case we are working with the original NTRU with the digital envelope and the ...
-1
votes
0answers
13 views

Cloning limitation of PCB [on hold]

Is it possible to clone the car key remote PCB? I am not sure wether that PCB cloned can copy the program from IC.
1
vote
1answer
16 views

What is the structure of a Server Key Exchange Message structure when using a psk identity hint?

I need to know the structure of a server key exchange message when using a psk identity hint. I know the general structure but I can't find an example of where the identity hint fits in. Thanks.
-1
votes
1answer
28 views

How to test digital signatures between two computers? [on hold]

I have to test a digital signature algorithm. I have two computers, one will be signer and the other one is verifier. I implemented both of these in C++ but I do not know how to test it. Computers are ...
3
votes
1answer
31 views

Is order of Correlation Immunity of AES S_box Zero?

I am working on AES S_box and trying to find out its properties like Correlation Immunity, Balancedness , Algebraic Degree , ANF form etc. These Papers 1, 2 give a nice definitions to above said ...
1
vote
0answers
21 views

where is ANS X9.31 used?

FIPS 186-4 mentions two standards for RSA: PKCS #1 and ANS X9.31. PKCS #1 is used with SSH, X.509, etc. What is ANS X9.31 used with? FIPS 186-4 has the following line: ANS X9.31, Digital ...
3
votes
1answer
86 views

Proof that a encrypted file has the same content as an (existing) original

Assume that Alice has a file F which she is going to send, in encrypted form, to Bob. Alice possesses F and the public encryption key K of Bob in form of an X509-certificate. She generates the file E ...
0
votes
0answers
8 views

Camellia Key Schedule Sigmas [migrated]

Camellia uses 6 sigmas in its key schedule with values ...
1
vote
0answers
51 views

Are there any digital signatures valid for multiple pieces of data?

Are there any digital signature algorithms that can be used to produce signatures valid for multiple pieces of data? For example: Pick a private key $k_{private}$, which has public key $k_{public}$. ...
3
votes
1answer
38 views

Does there exist an indistinguishability formal proof obfuscator?

A formal proof obfuscator is a mapping $\mathcal{O}$ such that whenever $P$ is a formal proof of a theorem $T$, then $\mathcal{O}(P)$ is a distribution of formal proofs of the same theorem $T$. An ...
1
vote
1answer
58 views

Do the Syllae algorithm and Malaysian cipher from Rubicon exist?

In the first episode of a tv series Rubicon (exactly in 482 and 491 lines of an English subtitles) there is mentioned “Syllae algorithm” and “Malaysian cipher”. I could not find any details about ...
0
votes
0answers
26 views

Problem when programming Schnorr signature [on hold]

I have some questions about Schnorr signature implementation. I am trying to implement it in C++. I chose private signing key x and public verification key y = g^x. I have a message M, random number ...
1
vote
0answers
15 views

How are keys stored in a .keystore file or in a .jks file? [migrated]

I would like to know what is the structure of the keys stored inside a .keystore or a .jks file? by structure I mean are the keys stored in key value pairs? how are the passwords for several keys ...
0
votes
0answers
26 views

How can I convert an image into a long hexadecimal code and vice-versa? [on hold]

Title. Characters to fill required 30 characters minimum.
1
vote
3answers
93 views

Public key decryption mathematical analogy

To clarify, I'm talking about digital-signatures, not public key encryption. When I encrypt something with a private key, then it should be decryptable with a public key, as I've understood how ...
5
votes
1answer
172 views

Applying machine learning algorithms to homomorphic encrypted data

I have a basic understanding of encryption and I got back to the topic because of an interesting site that encrypts financial data using homomorphic encryption (HE) and I would be happy for any input ...
-1
votes
0answers
48 views

what are the kind of mathematical proofs that i need to be familiarized with to understand (or do) cryptography? [on hold]

I know reductions are highly used to show that encryption schemes are secure under certain conditions, but i don´t know what other math proofs are needed. PD: English is not my native language so ...
3
votes
1answer
31 views

Using master password to encrypt and decrypt user credentials

I need a way to store third party credentials, and I want to avoid storing passwords in plain text. I can't use a hash because I will need to be able to get the raw password to log in to the third ...
1
vote
0answers
39 views

How would low-precision Gaussian sampling impact the security of BLISS?

For digital signature, I implemented BLISS in my cryptographic suite, and wrote the Gaussian sampler based on Lattice Signatures and Bimodal Gaussians. But unlike the reference implementation and ...
-1
votes
0answers
10 views

ocf-linux, Splitting large buffers into chunks < MAX_DATA_LEN [migrated]

I am using ocf-linux in an openwrt application and have run into OCF CRYPTO_MAX_DATA_LEN (64K-1) and E2BIG errors in CRYPTO_AES_CBC mode. As a consequence, I need to split the input buffer into ...

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