# All Questions

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### Is it possible to truncate AES output and keep uniqueness (no decryption needed)? [duplicate]

I would like to hash numbers less than 1000000000, so generally they could be stored on 30 bits. The aim is to obtain numbers that are not reversible, so my initial plan was to use SHA256 (with some ...
103 views

### How strong is XooDoo vs AES?

What is Gimli, and how does XooDoo compare to symmetric ciphers such as AES or ChaCha? I am looking at this library, called charm. Interesting paper here. I also ...
72 views

### Is that possible to calculate modular inverse of a point on elliptic curves?

Imagine that you are given a point $P$ so that $P=a\times G$. If you have no knowledge of $a$ is that possible to calculate point $I$ so that $I$ is the modular inverse of $P$? We know that over ...
44 views

### Fully homomorphic encryption noise reduction using modulus switching technique

Let we have the following encryption scheme such that, Encryption: $$C = m + r p^q \mod n$$ Where $n=p*q$ and $q, p>q$ are two large prime numbers as the private keys. Also, $n$ is the public key....
55 views

44 views

### What's the meaning of probabilities in differential privacy formula?

I don't understand what does it mean by "The probability is taken is over the coin tosses of K." Does it mean, the probability distribution is generated based on exactly same data but only the ...
32 views

### ECDSA dA multiplication algorithm [duplicate]

I was looking at this question and i can`t understand this part: QA = dA G = 5 (5,1) = (9,16) I saw that algorithm used for this was Double-and-add algorithm but i didn't get it. Can ...
75 views

### Can the person who decrypts a homomorphically encrypted value know what operations were run?

I'm looking at the SEAL library but I'm trying to figure out what happens in a certain use case. For example: Alice encrypts the number 123456 homomorphically and sends it to Bob. Bob adds 25 and ...
17 views

### Using PIN to enable MFA for YubiKey-based logon provider

I've created a custom credential provider (for Windows) that allows logon just by inserting a YubiKey. The user's Windows password is protected as follows: ...
88 views

### Talking TLS with EC cryptography and the secp256k1 curve [duplicate]

How reasonable would it be to speak TLS over the secp256k1 curve? My initial experiments show that OpenSSL supports it (albeit with special flags, see below): Running an OpenSSL client against an ...
11 views

### is it safe to AES encrypt the RSA private key and storing it in the database [migrated]

i'm building an app that really needs encryption of this type , my question is it safe to store the aes encrypted RSA key in the database ? here is how i encrypt the key : i generate a random 256 ...
91 views

### From the product of two permutation matrices raised to the same power, is it easy to find the power?

Let $A$ and $B$ be two public permutation matrices. If $r$ is a secret power of large number, can we easily find $r$ from $A^rB^r$?
547 views

### ECDSA: Why is SigningKey shorter than VerifyingKey

Total Crypto Noob here. I was wondering why in ECDSA the Signing Key is so much (half of) shorter than the Verifying key? Lets look at some python code: ...
Let $x$,$y$,$z$ be permutations. Then public key is $z=xyx^{−1}$ and $y$. Is permutation conjugate search problem easy? if yes, how to find $x$ from $z$ and $y$? Let be a is Alice's secret key as ...