Questions tagged [keys]

Private and secret keys consists of secret information used as input to various kinds of cryptographic algorithms such as encryption, signature and MAC to select the concrete transformation done by the algorithm.

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Need clarifications AWS Cloud HSM architecture [closed]

My apologies for the long post. I read on AWS docs that, when keys are generated using java keytool, the certificates are stored ...
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Symmetry shares

I’m sorry if this is already answered, however, regarding symmetric key components to create a symmetric key using xor (So eg comp1 xor comp2 xor comp3 = key) If in the case of an AES KEY, which goes ...
3 votes
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AES subkey calculation not working for subkeys beyond 0 and 1

How should I generate the remaining keys when performing subkey generation in AES encryption? I generated keys 0 and 1 first, but the other keys I generated later were wrongly generated, so what steps ...
6 votes
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Always set the IV to 0 randomized CBC

Please explain what goes wrong if we always set the IV to 0 in randomized CBC, and use the system to encrypt two different messages m0 /= m1 with the same key k. I ...
9 votes
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How strong are Bitlocker recovery keys?

This is an example of a bitlocker recovery key; 820042-335825-646573-481530-265253-688132-339900-822810 İs that key actually strong? It does not have any letters, ...
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X509 Client certificate - before - XEnroll / Certenroll / KEYGEN

Short story... IBM(now HCL) Domino have since way back a complete procedure to issue X509 client certificate as a login option to webserver. Back in 2010-ish it worked fine in both Firefox and ...
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Client Side Encryption For Web Apps

I want to build something where web clients encrypt some data server side and store it with me. However, I am not sure how to manage the user keys - ideally they can just sign in with social to access ...
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RSA Key Exchange Attack [closed]

I am curious what is an attack that the RSA Key Exchange algorithm is vulnerable to that Diffie Hellman Key Exchange is not vulnerable to? I know Diffie Hellman is prone to Man in the Middle attacks ...
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Keyspace in Encryption using Chaotic Maps

I wish to encrypt an image using Logistic map. A Logistic map can be specified with the Equation: $$x_{n+1} = r\,x_n (1-x_n).$$ Now, according to the Kerckhoff principle, the entire system's security ...
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Accidentally leaked my main gpg private key!

I only use one gpg key, which I use with pass, which currently holds a ton of password stuff. I also use that key to sign my github commits and a ton of other stuff....
3 votes
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AES first and last round key whitening

I've found this question from 2014 on Key Whitening: How exactly does key whitening manage to increase security? where is said that AES applies key whitening internally by adding a sub-key prior to ...
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Can the encryption with CTR mode be replaced by a publicly known unkeyed permutation when doing multiple encryption and keeping the IV secret?

A user of this forum answered in one of my questions and said that if the IV is kept secret in multiple encryption with CTR mode, the cost of breaking the scheme is $${2^{2 l_{key}}} 2 \cdot {2^{l_{iv}...
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What qualifies as a key?

For my own project and the fun of it I have created an algorithm that turns plain text into cipher by interacting between entered text and a given password. My question is, in this instance, does the ...
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Is BLAKE2X suitable for generating keys with any security in bits event if BLAKE2 having only 256/512-bits?

I can generate a key of any security in bits with any hash function from random source with enough entropy by using the following scheme: $$H(00||S) || H(01||S) || H(02||S) || H(03||S) || \cdots$$ /\ ...
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Encrypting with CBC then XORing repeatedly a chunk of random data smaller than the plaintext: Is there a gain in security?

If I encrypt a 1MiB file with AES-CBC (or any other cipher) and XOR a 128KiB of (truly) unpredictable random data repeating until the end of file, will I have a security of 1048576-bits (128KiB*8)? ...
5 votes
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Is it possible to create a pseudo-One Time Pad by using a key smaller than the plaintext?

Let's suppose I want to encrypt a 10GiB file but I don't want to use a One Time Pad, just a 1MiB key taken from /dev/random (in Linux). I know that the key should not be repeated, but is it possible ...
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Hashing a seed together with a block counter and using as a encipherment scheme: What scheme is more secure in practice?

This question is related to this (but it is not the same). Let's suppose I have a seed with an entropy of 1024-bits and hash it with a counter using a hash function with one-quarter of the seed size ...
1 vote
1 answer
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Signature operation of RSASSA-PKCS1-v1_5 requires private key. Superficial limitation, or are public parameters mathematically incapable of it?

In the case of RSASSA-PKCS1-v1_5, is it simply that the cryptographic libraries and APIs are designed to only sign if determined superficially that it has a private key, or is the public key ...
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Blom's key distribution

Having a difficult time wrapping my head around the Blom's key distribution. I found an online resource to understand this but still couldn't get it. I am attaching the screenshot from the book where ...
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How much computation it takes to crack a PBKDF2's secret salt when the passphrase meterial has been leaked

Given the following code, extracted from a Bip39 implementation for Android by Zcash ...
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1 answer
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Standardized names of cryptographic algorithms

I am using micro-services to interact between various cryptographic technologies like HSMs, keystores, vaults, etc., that are written in different languages. Usually, each technology, or even vendor, ...
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1 answer
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Hashing a seed together with a block counter and using as a encipherment scheme: Will this have the same security in bits as the seed used?

A user of this forum said that the whole entropy of a seed goes to the hashed result if using a counter and also that is suitable for key generation even if the internal state or digest size of the ...
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Encrypt messages for two-participants chat

I need a chat between two users and I obviously want to make it as secure as possible. I am, by no means, a cryptography expert, so I turn to you guys for some advice. Because I like the idea of ...
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Is it possible to generate a key from a hash function, being the key larger than the hash function digest output without spliting the seed?

Let's suppose I have a 2MB photo and I want to generate a key from it, and the key should have 2048-bits of size. A hash function such as SHA3-512 would not deliver a key with with the desired ...
2 votes
1 answer
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Streams Ciphers - Linear feedback shift register logic behind design

I’m just seeking a better understanding as to the logic behind design of the A5/1 cipher’s keystream generator. Why are the registers degree chosen in such a fashion (19,22 and 23 bits long ...
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Risk scenarios when hosting KEK in Google Cloud KMS HSM backended [closed]

For some time now, we have been assessing the risks from a GDPR perspective when data (data-at-rest) in the Google Cloud is fully encrypted using native means. This means that we create both the KEK ...
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Generate SHA256 fingerprint from RSA public key (string only)

I have the public key, the string itself (not a file), and I am trying to figure out the SHA256 fingerprint, as in the image attached. The default key generated by PuttyGen is SSH-2 RSA with a SHA256 ...
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Storing keys in HSM program flash

We are using an Infineon uC TC233 for a cybersecurity based development. It has HSM but no HSM Data Flash (DF1) present. Our host side application will call HSM APIs itself for any crypto service. ...
3 votes
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Can initialization of the Spritz cipher state by a randomly chosen permutation securely act as a key?

The Spritz cipher is a "sponge-like" construction that the authors show can be used as a hash, MAC, stream cipher, re-seedable pseudo random number generator, and/or an authenticated cipher. ...
2 votes
2 answers
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How to destroy a randomly generated key after using it?

for example, I have an encryption program like this: Input: a message, M; my public key Kpub Step 1: randomly generate a ...
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In a Diffie-Hellman key exchange Find this key and compute the shared secret key k

Hi I struggling to find the answer of my schhol exam, can anyone help me . In a Diffie-Hellman key exchange the multiplicative group of integers modulo p is used with the parameters p = 59, g = 3 mod ...
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What is the importance of superencryption?

Please, can any extensively explain the importance of super encryption in relation to attacks experienced by single standard algorithms
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Cryptography methods that allow for multiple keys to be used?

I'm currently working on a webapp in which I'd like all nearly all user data to be encrypted, but accessible by multiple users (ie a doc encrypted should be decrypt-able by parties A, B, C, all ...
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Do PQ-KEMs kyber and KEMs approved for 4th round , need Domain Separation?

Do PQ-KEMs Kyber and KEMs approved for 4th round , need Domain Separation for deriving multiple keys from shared secret?
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Is libsodium's Key Exchange system secure?

I'm building a project using libsodium's AEAD + Key Exchange system and want to write a proof justifying the security of the project. I am wondering if I can find a source detailing the exact security ...
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How do I decrypt an encrypted message with an RSA private key?

I have an encrypted password I must decrypt as part of a challenge. Along with the password came a few UNENCRYPTED RSA private keys From what I understand, all I need in order to decrypt the password ...
1 vote
1 answer
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How can I distribute a set of anonymous tokens digitally among a known limited population to do anonymous voting?

TL:DR How can I give a population of N people the chance to randomly pick one token each person guaranteeing those: Nobody knows noone else's token. Noone can pick more than one token. Every person ...
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2 answers
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bitcoin public address cryptography

I was learning about bitcoin cryptography and seen some strange bitcoin public addresses like this 1Lets1xxxx1use1xxxxxxxxxxxy2EaMkJ 1fuLL1xxxx1power1xxxxxxxxxxzatvCK ...
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Are there any encryption schemes where more than one key give the same encryption and decryption operations? [duplicate]

Given an encryption scheme that takes as input a key $k$ and converts it to an encryption operation $E$ via the function $M(k) = E$, is it possible that more than one $k$ can give the same $E$? For ...
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Tools to debug handshake failure after client key exchange, change cipher spec and encrypted handshake message TLS1.2

Hello I have been receiving Description : Handshake failure after sending client encrypted handshake message to the server. Is there any tools I can use instead of wireshark to detect the source of ...
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Multi key layered encryption verification

Is it possible to take some value text like “Hello World!” And encrypt it with a random key. Then take the encrypted message and encrypt it again with another random key. And so on… Then can you write ...
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What is a ciphering key?

In Hebrew language there is the term tzophen (צופן) which means cipher. There is also a term "maphtech hatzpana" (מפתח הצפנה) which means "ciphering key". What is a ciphering key? ...
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Key distribution protocol involves only 2 parties, given E[k1,E(k2,m)]=E[k2, E(k1, m)]

Given an one-key cipher such that: $E[k_1,E(k_2,m)]=E[k_2, E(k_1, m)]$ Is there any key distribution protocol that involves only two parties (Alice and Bob) without the key distribution center? The ...
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Proving you're from the year 2069

Just a question I thought of while playing an amazing game about time travel (13 sentinals aegis rim). What are the most bullet-proof cryptographic methods for proving you've come from beyond a ...
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predict random keys using python [closed]

How can I write a program in python to predict the random key (urandom) that is used for encryption? I tried to search and I couldn’t find anything related to guessing and predicting urandom in python
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Generating multiple keys to decrypt one encrypted file

I've come across this particular design where I have one file encrypted. Then multiple people may want to access the file and I want to generate an individual key for each person, but each individual ...
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Can I decrypt AES-CBC ciphertext if I have the key without IV? [duplicate]

Can I decrypt ciphertext from AES-CBC encryption, if I have the key and ciphertext only?
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How proxy re-encryption works - layman perspective

Here is the use case: A uses B's public key to encrypt a message and sent it to B. In later stages, a new member C joins and B would like to let C be able to see this encrypted message (i.e., give the ...
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Entering a word in a S-Box (like Feistel ciphers do) and keeping the S-Box secret: Could this be called encryption?

Let's suppose I take a data block of 64-bits and use it as an entry in a (big) S-box, and keep the S-box secret. S-box would be the "key". For "decryption" I just enter the result ...
2 votes
1 answer
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Generate a key with a size bigger than the hash output length/security, is it possible? [duplicate]

Let's suppose I want to generate a 2048-bit key from a hash function with security up to 512-bits (such as Blake2b). I take 4 high-resolution photos, hash them with a hash output length of 512-bits ...

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