Let n = pqr where p, q,r are distinct primes. Describe an efficient algorithm that, given both n and φ(n) = (p−1)(q−1)(r−1), outputs the factors p, q, r.

# Tag: cryptography

## cryptography – Probability of Hash Collisions

I’ve been looking into hash functions and I was wondering, let’s say that we have a cryptographic hash function that produces 60-bit outputs,

Let’s say Hash(1) = 0000….(60 zeroes) If you don’t know anything more

about the hash function, what is the probability that Hash(2) = 00000…..(60 zeroes) as well?

Also, what’s the probability that the hash function has at least one

collision?

My thinking was that since hash functions are uniform, that would mean that the probability of it being the same hash result as another would be the same.

However, when it comes to collisions I know the birthday problem means that the probability is greater than an equal chance.

Any clarification would be great.

## digital signature – Why are LMS and XMSS no candidates in the Post-Quantum Cryptography Standardization process?

Why are Leighton-Micali Signature Scheme (LMS) and eXtended Merkle Signature Scheme (XMSS) no candidates in the NIST Post-Quantum Cryptography Standardization process?

Both are mentioned in the final draft of Recommendation for Stateful Hash-Based Signature Schemes.

I was expecting that both algorithms are candidates in the standardization process as well, but it seems that they weren’t even submitted. Can anyone explain why? If they are not considered as candidates for a new standard why does the Recommendation for Stateful Hash-Based Signature Schemes exist and mention exactly those two algorithms?

Is the recommendation just a temporary standard until the standardization process is finished?

## cryptography – best platform to invest bitcoin

-Trade Spot Market is an investment banking boutique dedicated to serving innovative media companies worldwide whose head office is based in the Canada.

It offers a wide range of services, designed to help both traders and Bitcoin miners invest their funds / Bitcoins at great interest rates. It is based in Canada and have investment professionals from advanced computer technology to engineering. Join the platform and start getting profit with professionals in just 168 hours!.

## cryptography – Start mining with 2GPUs vs Re-selling for profit

I currently own a rtx 3060ti and 3070 (bought them at 503usd and 657usd on january 2021) I wanted to ask if I should start mining ethereum with these two rigs or should I just re-sell them right now. If I start mining, I already have:

CPU: i5-10400f x2

PSU: Thermaltake 750W (80+ Gold) / Corsair 650W (80+ Bronze)

Motherboard: Asrock b460 phantom gaming 4 / Asrock b460 pro 4

RAM: Corsair Vengeance DDR4 (8GBx2) / Gskill DDR4 16GB/3200 sniper x

SSD: Corsair M.2 PCIe 480GB

Since I have two gaming computers, I want to use the components from one of them to create a 2GPU rig. I’m planning to buy a cheap GPU to replace my current PC since I rarely game nowadays. The extra costs are the GPU risers and frame which are cheap.

## cryptography – Shared crypto hardware wallet

We were all newbs at the beginning, and did things the wrong way.

My partner and I bought crypto separately with our own exchange accounts, but transferred our hodl coins to a single shared hardward wallet address.

Using Koinly, we can easily determine which transaction in is for which (only 15-20 or so)

Problem/challenge is, how will this work when i transfer the coins out using FIFO, LIFO. We Koinly know which “coins” are which?

I have never actually transferred out from the hardware wallet, and i want to fix this.

I thought about transferring all coins out to our respective exchanges (at the same time), then back into new separate wallets. Will this work and be cool to the ATO?

Second question. Can you have a share wallet address for a masternode and split payouts/cost by the % coin holdings.

Thanks

## cryptography – True or scam: registering for new cryptocurrency “TRON” awarding free 300 points for invitation

## cryptography – Find Password from Hash value using SHA3 Algorithm

I am not able to solve this, please someone help in that how to got password for this.

**Cipher**

You see the following written on the panel:

686562640000000080028C0961EE6169EA6FEFED61EE6169820A8D8961EE6169

0208018000000000820A8D8961EE61696A6D63E4000000006865626400000000

You must be wondering about these numbers. This is the hash value of your password which is created by a toy version of SHA3. This version of SHA3 has only three step mappings:

Theta, Pi, Chi. Also, the password is no more than 16 characters.

Toy Version of SHA-3 is given below-

```
char str(str_length);
char hexa(16) = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
uint64_t b = 1600;
uint64_t l = 512;
uint64_t c = 1024;
uint64_t r = 576;
int rounds = 24;
int i, j, k;
uint64_t state(5)(5)(64), tempstate(5)(5)(64);
for(i = 0; i < 5; ++i)
for(j = 0; j < 5; ++j)
for(k = 0; k < 64; ++k)
state(i)(j)(k) = 0;
uint64_t message(r);
k = 0;
for(i = 0; i < str_length; ++i){
for(j = 7; j >= 0; --j){
if(((str(i) >> j) & 1) == 1)
message(k) = 1;
else
message(k) = 0;
++k;
}
}
while(k < r){
message(k) = 0;
++k;
}
for(k = 0; k < r; ++k)
state(k/(64*5))((k/64) % 5)(k%64) = message(k);
uint64_t current_round = 0;
uint64_t column_parity(5)(64);
while(current_round < rounds){
//theta operation
for(i = 0; i < 5; ++i){
for(k = 0; k < 64; ++k){
column_parity(i)(k) = 0;
for(j = 0; j < 5; ++j)
column_parity(i)(k) ^= state(i)(j)(k);
}
}
for(i = 0; i < 5; ++i){
for(j = 0; j < 5; ++j){
for(k = 0; k < 64; ++k){
state(i)(j)(k) ^= column_parity((i+4)%5)(k) ^ column_parity((i+1)%5)(k);
tempstate(i)(j)(k) = state(i)(j)(k);
}
}
}
//pi operation
for(i = 0; i < 5; ++i)
for(j = 0; j < 5; ++j)
for(k = 0; k < 64; ++k)
state(j)(((2 * i) + (3 * j)) % 5)(k) = tempstate(i)(j)(k);
//chi operation
for(i = 0; i < 5; ++i)
for(j = 0; j < 5; ++j)
for(k = 0; k < 64; ++k)
tempstate(i)(j)(k) = state(i)(j)(k);
for(i = 0; i < 5; ++i)
for(j = 0; j < 5; ++j)
for(k = 0; k < 64; ++k)
state(i)(j)(k) = tempstate(i)(j)(k) ^ (~tempstate(i)((j+1)%5)(k) & tempstate(i)((j+2)%5)(k));
++current_round;
}
uint64_t index;
k = 0;
while(k < l){
index = 0;
for(j = 3; j >= 0; --j)
index = index*2 + state(k/(64*5))((k/64)%5)(k%64 + j);
printf("%c", hexa(index));
k += 4;
if(k == 256)
printf("nt");
}
```

## cryptography – LSFR sequence, find a triple satisfying a sequence

I’m learning about LSFR systems and I have to solve the problem:

Given is a sequence x_{i} = a * x_{i-1} +b (being an element of Z_{m}.

Find a triple (m,a,b) for sequence 13, 223, 793, 483,

213, 623, 593.

I’m learning about cryptography at the moment but I’ve never done such a calculation

before (with the modulus m). I think I have to solve a system of 3 equations?

But I don’t know to deal with the modulus.

Please maybe someone can help me.

Thanks

## encryption – auto-key chiffre – Cryptography Stack Exchange

Auto key chiffre:

*A = B = K = L = Z*_{n} , n ≥ 2. The keystream is given by z_{0} = K ∈ *K*, z_{n} = x _{n−1} für

n ≥ 1.

The encrypted text is y_{0}= x_{0}+K, y_{i}= x_{i} + y_{i-1}.

The question is: is this a good encrypting?

May somebody help me answer this question?