# All Questions

0answers
22 views

### Why doesn't COMODO use their root cert for the SSL certs they sell? [migrated]

I noticed that OS X ships with a COMODO Root Certificate, but that the certs they sell to websites stem from the AddTrust External CA Root. Why is this?
0answers
23 views

### How to find the crypt algorithm from a table of crypt vs results? I guess this is MD5 [closed]

Im new on Crypt things, I want to know how to find the "salt" or the algorithm used to convert this strings. I read long time ago about this but for get it even how this process was named. I guess ...
0answers
8 views

### Does we need IV if we're generating a new Symmetric key for every message? [duplicate]

We need to encrypt individual messages, for every message we: Generate a new AES key Encrypt the message with the key (AES/CBC/PKCS5Padding) Encrypt the symmetric key with with a public key ...
0answers
5 views

### Length of output of AES 128 encryption in python [migrated]

When I am trying to convert to hex the output of my AES 128 encryption code using pycrypto. I am using hexlify .the output is 64 bits for a 32 bits input. The output is always double the size for any ...
0answers
34 views

### XOR + HMAC security analysis? [closed]

I'm new to cryptography don't mind me if I'm asking anything invalid.I'm working on security in Device to Device communication based on LTE-A. Can anyone please explain about analyzing some of the ...
0answers
32 views

### Database of Cryptographic Hardness Assumptions [closed]

I'm looking for a specific website that lists all of (or many) of the hardness assumptions used in cryptography. The website lists the problems along with a short explanation and references. ...
0answers
67 views

### Can I get the private key through the public key in RSA? [closed]

I want to obtain private key in RSA to decrypt a msg. Decrypt -> M = C^d (mod n) I know that: Crypted msg (C) = 0x293D9E806D9F9040E52F71B4026FD5AA95D965E7319728F220ADB44794CEA3D6 Public key ...
1answer
29 views

### What values constitute failing for ENT tests?

The dieharder tests give a clear PASSED, WEAK, etc and I'm wondering what those thresholds ...
0answers
24 views

### Identification schemes: Okamoto

I am reading Cryptography theory and practice by Stinson. The book is talking about the proof of security of Schnorr and Okamoto schemes. It claims that if an impersonater can find (in the case of the ...
1answer
35 views

### Collision Probability of MD5 over different attacks

I am researching on collision probability of MD5 on various attacks against it. Can someone help me with finding what is the least probability that there will be collision in specific attack on MD5 ? ...
1answer
38 views

### Cryptography in wireless medium

.i'm new to this Area. Que. how do i implement asymmetric key algorithm into wireless medium using ns 2.35 ? e.g. node A is a sender and B is a receiver now A is sending a pkt using Bs public ...
1answer
35 views

### Problems implementing AES in CBC+CTS mode

I'm trying to implement an AES cipher in CBC+CTS mode, but I'm unable to get the second last plaintext block to decrypt properly. I've attached my code, it's based on the steps listed under CBC ...
0answers
7 views

### What if the Local Windows Cert Store is Compromised? [migrated]

The diagram below illustrates chaining digital certificates up to a publicly trusted Root Certificate: I have been researching how trusted root authorities (such as GlobalSign or Verisign) are used ...
0answers
14 views

### Need of highest MAC tag size in AES CCM, when using CTR + CBC-MAC (not CBC MAC only)

Assuming that AES CCM is used with respect of the NONCE unicity // the key life cycle, I wonder about the need of using the highest size for CBC-MAC authentication tag if CTR mode encrypts both ...
0answers
19 views

### how to implement order preserving encryption except cryptdb

Which cryptographic algorithm is suitable for implementing order preserving encryption with out using cryptdb
1answer
20 views

### Stern identification scheme to signature scheme

I'm trying to understand the comment in the page 103 of the book Postquantum Cryptography. about convert the identification Stern procedure for signing. Can you write an example of signature of this ...
0answers
5 views

### Saving passwords in database [migrated]

I recently studied a lot about writing secure codes and choose secure method to save the password in database. My question is: is it secure to use ready made libraries or API's for this reason? How we ...
0answers
6 views

### where to store the salt for “crypto_pwhash” in a web application with no local storage [migrated]

I am developing a web application which stores encrypted data on a server. To derive the encryption key as well as the login key, I want to use libsodiums crypto_pwhash. To use this function it needs ...
0answers
14 views

### Massey-Omura three pass protocol prime modulus share

In Massey-Omura three pass protocol: how many bits long should be the prime modulus $M$ in order to be secure? should be the the $M$ secret? should be the $M$ generated every time or it could be ...
3answers
51 views

### Computational indistinguishability: are function parameters known?

I would like to clarify something about the definition of computational indistinguishability and pseudorandom number generators. Suppose we wanted to show that linear congruential generators of the ...
1answer
26 views

### Trying to understand the constant factors (19 and 38) in Ed25519 ref10 function 'fe_mul'

I would like to transpose the Ed25519 ref10 implementation to a similar twisted Edwards curve that is based on another prime, in order to have the same speed optimizations in place for the new curve. ...
0answers
15 views

### DSSP reduction to DSSI

In “Towards quantum-resistant cryptosystems from supersingular elliptic curve isogenies" by DeFeo, Jao and Plut (PDF), there is a reduction from the Decisional Supersingular Product (DSSP) problem to ...
0answers
26 views

### implementation of digit serial architecture

I am working on architecture of SIMON cipher where I have to use either bit serial, parallel or digit serial to implement the algorithm for each round function and also for sub-key generation. So I ...
0answers
58 views

### Multiplicative inverse ($17^{-1} \mod 31$)?

So. Sorry for bothering you with such a simple question, but I can't really get this done. It's just an exam question in which I need to use CRT in order to calculate the RSA signature of a msg ...
0answers
29 views

### Encrypt with K1, K2 and decrypt in opposite with K2, K1 [duplicate]

When using symmetric cipher, does the following statement holds: E(x, k) means encrypting x with key k in ECB mode ...
0answers
22 views

### RSA-PSS salt size in certificate

In RFC 4055, the signature RSAPSS algorithm has the following ASN 1 parameters: ...
0answers
33 views

### one complex password as a “seed” for localy generated per-service passwords

I've stumbled upon a project that suggests a way of having to remember one password, from which a “per-service password” could be generated by salting the service name using scrypt. What could be a ...
1answer
63 views

### How to crack SHA256 only letters

I recently created a program that hashes a password using SHA256 and potentially using salt. How can I crack that if I know that the password only contains lowercase letters?
0answers
30 views

0answers
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### RSA: If I sign the same digest with same key twice, will the signatures be identical? [duplicate]

If I don't have public keys to verify the signature, can I use this to discover that two signing services are using the same key? Can you send a reference?
0answers
10 views

### Creating disk image of encrypted disk [migrated]

I'm Fedora 21 user for some time and I'd like to create disk image to escape installing everything over again when something fails. I have encrypted storage and that fact makes me wonder. How do I do ...
0answers
36 views

### Cryptographic Disk wiping with quantum random data?

I was thinking about using 4 Quantum Random Number Generators working at the same time to create a secure disk wiping system. Basically feed the random bits into to an approved DRBG then through an ...
0answers
3 views

### Why do some programming language API's not support private key passwords? [migrated]

Two questions: I've recently started building a basic Go web-server, and noticed that the API for starting a TLS web-server does not support a symmetrically encrypted private RSA key. The API is ...
0answers
43 views

### Fast mental encryption algorithm? [duplicate]

Are there any algorithms that exist to encode messages written with pen and paper such that the messages can be encrypted/decrypted mentally? For example, Bob thinks of the text "This is my ...
1answer
47 views

### TLS encryption with a self-signed PKI and Python’s asyncio module

I want to enable TLS encryption with a custom / self-signed PKI for a self-contained distributed system built with Python 3’s asyncio. I’ve read Python’s ssl docs as well as several tutorials: ...
0answers
33 views

### Establish authentication

I have designed a basic authentication scheme where two nodes will mutually authenticate that other holds a shared secret. I have very limited RAM/ROM (its on uC) and bandwidth. Here it goes: ...
0answers
45 views

### Type of values that can be accumulated in bilinear map (multiplicative) accumulator reg.

Is there any restriction that the members to be accumulated in bilinear map (multiplicative) accumulator need to be relatively prime to P? Where P is the order of group.
0answers
84 views

### What is the danger if a non-prime is chosen for RSA? [duplicate]

I was reading this question about generating primes for RSA keys. The answers point out that most implementations of of the algorithm use probabilistic prime-ness checking algorithms. The answer by ...
0answers
36 views

### Side channel attack on FPGA AES engine

I actually don't know if this is the right place where ask, but I try. The side channel attacks aren't a negligible problem. There are several ways to protect from these attacks its own IP inside the ...
1answer
51 views

### What is more efficient, pairing based cryptography or non pairing based cryptography? [closed]

As far as I know non pairing pairing based cryptography is less time consuming than pairing based because, pairing based uses complex operations. Are there any advantages of pairing based cryptography ...
1answer
22 views

### SSH rekey security implications

When an SSH session is rekeyed due to either the time limit or data limit for rekeying having passed, does the Diffie-Hellman exchange take place within the encrypted channel provided by the existing ...
0answers
9 views

### What is search space of this problem? [duplicate]

I have an exam and i have no time to solve this problem(I think about it a lot but i do not solve it).please help me and solve it for me: $A$ is a random number and has $512$ bits.We make $B$ ...
0answers
41 views

### How to show the inner workings of ECC?

I will be giving a short (10-15 min) presentation on the fundamentals of elliptic curve cryptography, and I would like some suggestions on how to show the basic workings of asymmetric key exchange on ...
1answer
36 views

### What does the acronym “CRT” stand for in the PKCS #1 specification?

What does the acronym "CRT" stand for in the PKCS #1 specification? Does it stand for "Chinese Remainder Theorem"? Thanks, Pete
1answer
65 views

### What's the structure of server-key-exchange message during TLS handshake

Here is a relevant question: With OpenSSL and ECDHE, how to show the actual curve being used? Using ...
0answers
36 views

### pseudo random generator from length preserving one way function which is not permutation!

Is it possible to construct a pseudo random generator from a length preserving one way function which is not a permutation????

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