Questions tagged [key-generation]

Key generation is the process of generating keys for cryptography. A key is used to encrypt and decrypt whatever data is being encrypted/decrypted.

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239
votes
7answers
42k views

How do certification authorities store their private root keys?

Knowledge of a CA private key would allow MitM attackers to transparently supplant any certificates signed by that private key. It would also allow cyber criminals to start forging their own trusted ...
138
votes
7answers
75k views

Best Practice: ”separate ssh-key per host and user“ vs. ”one ssh-key for all hosts“

Is it better to create a separate SSH key for each host and user or just using the id_rsa key for all host to authenticate? Could one id_rsa be a malpractice for the privacy/anonymity policies? ...
7
votes
4answers
8k views

Calculate time taken to break AES key

A 256 bit AES key is required to be broken using the brute force method on a 2GHz computer. How long would it take to break the key in the best case and in the worst case situations? Assume that 1000 ...
22
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4answers
9k views

Generate cryptographically strong pseudorandom numbers in Javascript?

Is there any good way to generate cryptographically strong pseudorandom (or true random) numbers in Javascript? The crucial requirement: if a.com's Javascript generates some random numbers, no one ...
12
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2answers
1k views

Can the human brain generate cryptographically secure random numbers?

A security conscious friend of mine was attempting to generate entropy using random dice rolls to generate a random password, and I became curious about the security of random number generators and ...
13
votes
3answers
738 views

Can I use the same password both for SRP and for client-side encryption?

Suppose a less-than-trusted server is used to store users' confidential data (encrypted at the client side), and both tasks - authentication and encryption/decryption - should be doable with a single ...
9
votes
1answer
1k views

Would it make sense to use Bcrypt and PBKDF2 together?

I've read various opinions about whether Bcrypt or PDBKF2 is a better key derivation hashing method. The answer seems to depend on a lot of complicated factors that are not easy to analyze. Would ...
32
votes
6answers
26k views

What does key signing mean?

What exactly does the "key signing" mean? So for example I have a private/public GPG key so that people could send me encrypted e-mail, because they know my public key. But: what does key signing ...
157
votes
4answers
168k views

SSH key-type, rsa, dsa, ecdsa, are there easy answers for which to choose when?

As someone who knows little about cryptography, I wonder about the choice I make when creating ssh-keys. ssh-keygen -t type, where type is either of dsa,rsa and ecdsa. Googling can give some ...
14
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5answers
11k views

Generate a PGP key with more than 4096 bits?

I would like to know if generating a PGP key with a number of bits higher than 4096 is possible and if so how?
25
votes
1answer
11k views

Where do I get prime numbers for Diffie-Hellman? Can I use them twice?

I realise it's very hard to generate suitable prime numbers and generators for the Diffie-Hellman key exchange. What is the best way to generate them? And if I have one, can I use it twice? ...
15
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4answers
11k views

What are you doing when you move your mouse randomly during a truecrypt volume creation?

Is that called a 'round' every time you move your mouse when creating a new volume? I'm talking about the screen with the random numbers during the volume creation process. What is the purpose of ...
1
vote
3answers
1k views

Why should you generate SSH keys on client devices?

Most tutorials for setting up SSH recommend generating the keypair on a client machine. Why exactly is this? Assuming your communication lines are not compromised, and you delete the private key from ...
4
votes
1answer
159 views

New certificate but what about the keys?

One of our SSL certificates has expired and along with that so has the keys. I have a re-newed certificate but no re-newed keys. The posting Should I change the private key when renewing a ...
27
votes
1answer
15k views

JSON Web Tokens - How to securely store the key?

I was building a RESTful Web Service when I came across JSON Web Tokens as an alternative to traditional cookies for authentication. The conceptual core of this method is that the server is the only ...
31
votes
1answer
30k views

How should API keys be generated?

I want to make sure requests can't be forged and sent on to my server. In order to do this I need to generate an API key per user on my system. The purpose of the key will be to sign requests on the ...
16
votes
2answers
416 views

What research suggests that user's mouse movements are (not) sufficiently unpredictable for secret key generation?

I have not been able to find any credible source which tried to prove or disprove the randomness of mouse movements. A Google Scholar search for "mouse movement entropy" gives surprisingly few ...
23
votes
4answers
21k views

Why OpenSSL can't use /dev/random directly?

I couldn't find the answer for the reason anywhere, even the wiki page doesn't explain it. This seems like using a PRNG for seeding an another PRNG. The first one (/dev/random) may itself be seeded by ...
7
votes
3answers
6k views

Where does StartSSL generate the cerificate, server or client-side?

I.e. do really only I have the private key or do I have to trust that StartSSL (or any other provider) don't store it themselves?
10
votes
1answer
4k views

Using HMAC to generate secret keys

I am developing a platform that uses several secret keys for several usages: key1 for hashing passwords (using pbkdf2-hmac-sha256), key2 to generate non-repeating unpredictable uuids (using aes-128 ...
7
votes
1answer
21k views

Create RSA public, private key pair having numbers generated already

I want to know how to generate working RSA key pairs, with the correct syntax. Let's say I have already generated somehow my numbers for a 512bit key, which are: e = 00065537 d = ...
0
votes
2answers
6k views

Which default encryption does OpenSSL use?

If I create a private key via: openssl req -x509 -newkey rsa:2048 -out cert.crt then OpenSSL writes the private key to the file privkey.pem and if you do not provide the -nodes parameter it will ...
9
votes
3answers
2k views

How can you securely generate keys on AWS?

Our application needs to generate secure keys for long term storage on AWS using openssl. But I've seen some instance where entropy falls dangerously low on AWS machines and this doesn't appear to be ...
7
votes
1answer
321 views

Preparing to change over to new GPG-key - what to do with my old ones?

I've just created a new off-line GPG-key with a sign/certify master-key and two sub-keys - one for signing and one for encrypting. 5 yr expiration for the master, 2 yr for the subs. My master-key got ...
6
votes
4answers
3k views

SSH: reusing public keys and known-man-in-the-middle

Usually, people recommend to use a single private-public key pair everywhere (if we're not talking about a possibility of compromising the private key): Best Practice: “One per-user ssh key” or “...
3
votes
3answers
730 views

Is it safe to generate a password for a user during sign up in a web application?

I'm working on updating a web application. It currently creates a password for a user during sign up. Is asking the user to create the password themselves safer than relying on a generated password?
11
votes
4answers
4k views

What's the best length for randomly generated passwords? (Security vs. compatibility)

It's generally recommend to use a unique password for each online service, a random password generator to create them and a password manager to store them. I've started to replace all my online ...
9
votes
1answer
558 views

Is a 43 character GPG (symmetric) passphrase as secure as a 256-bit key?

A 43 character securely randomly generated mixed case alphanumeric password (with 2 extra chars to give 64 possibilities per character) would constitute 258 bits of entropy (6 * 43 = 258). Since the ...
2
votes
3answers
1k views

What is the recomended algorithm to create a key from a password?

In my new secret document encryption utility, the key for symmetric encryption = the hash of a random salt and a user provided password. It is necessary to have a slow hash function in order to ...
9
votes
1answer
3k views

HKDF and key stretching

I thought that all key derivation functions would do a key stretching phase, by iterating some kind of process. But I can't see that process in HKDF. HKDF doesn't do key strengthening? If I have a ...
5
votes
1answer
299 views

Why is the Key Derivation Function important?

Let's consider this openssl command : openssl enc -aes-256-cbc -pass pass:PASSWORD Why is it important to have a good Key Derivation Function? This answer to another question suggest that GnuPG is ...
5
votes
2answers
3k views

TrueCrypt and Keyfiles hidden among 500,000 other .pdf files

A question from a newby: I have a USB or Standalone HardDrive with a TRUECRYPT hidden partition on it that needs one or more "keyfiles" and a password to access. What tells the attacker what kind ...
4
votes
0answers
3k views

Which ECC to choose with GPG?

I want to generate a key pair with gpg2 2.1.11 and libgcrypt 1.6.5. I use the command gpg2 --expert --full-key-gen. This allows me to choose an ECC: Please select what kind of key you want: (1) ...
4
votes
3answers
498 views

Could using a generated key from an online service be considered a risk?

With some colleagues we're having a debate regarding the randomkeygen.com website. I do think that there is a security risk using the generated keys of this (or any of this kind) website. Why ? ...
3
votes
1answer
478 views

Are WoSign S/MIME certificates generated on the server side and therefore unsafe to use?

WoSign has been in the media for offering free server and client certificates. Since one of my (free) S/MIME certificate from another CA is about to expire soon after one year and WoSign offers ...
3
votes
1answer
323 views

Should I revoke & regenerate PGP private keys after computer is serviced by Apple Store?

I recently had an issue with my MacBook where it wouldn't boot. So I took it in to the apple store, and they said that they would need to send it off to a service center to diagnose and repair it. I ...
2
votes
4answers
6k views

Does a renewed certificate open old messages?

I have a digital certificate that I use to exchange messages with peers, my certificate expiration date is due next year, suppose I renew this certificate before it expires, will I be able to open the ...
1
vote
1answer
749 views

Security without TLS certificates

after getting an answer to Security over multi-streaming such as SCTP i have found that i do not have the capacity to give a public key or certificate to the other end securely (to be sure MitM cannot ...