Linked Questions

-1
votes
3answers
130 views

Are 21 characters enough to restore a PGP key?

The german e-mail hoster web.de offers PGP encryption with Mailvelope now. To transfer your private key to another browser, you can use a 21 characters long recover key. How does this affect the ...
-1
votes
3answers
1k views

find password and iv of an encoded string knowing the decoded string

If I would know the clear and encoded versions of a string could I somehow find the password and.or iv that wore used to encode it? Encoding done with open_ssl aes-128-cbc.
27
votes
2answers
36k views

Recommended options for LUKS (cryptsetup)

I'm looking for recommended options for cryptsetup to create fully encrypted SSD (SanDisk SSD U100 128GB), which achive: Timing O_DIRECT disk reads: 1476 MB in 3.00 seconds = 491.81 MB/sec Timing ...
22
votes
2answers
1k views

Does holding an AES-encrypted string and its cleartext from a database help an attacker in decrypting other parts of the database

I have a question regarding Encryption. Say an attacker stole my entire database. In that database all the data was encrypted. If the attacker took one piece of encrypted data and for some reason knew ...
15
votes
2answers
22k views

Why does Google prefer ECDHE-RSA-AES128-GCM-SHA256?

I want to configure my new mail server secure as possible and wondering about the used cipher while connecting to Googles SMTP server. I'm curious why they prefer the cipher ECDHE-RSA-AES128-GCM-...
12
votes
2answers
2k views

How can a passphrase with 256 bits of entropy practically be constructed & memorized?

Quoting Wikipedia: A password with, say, 42 bits of strength calculated in this way would be as strong as a string of 42 bits chosen randomly[.] Assuming that interpretation is correct, combined ...
11
votes
2answers
1k views

Unseen.is encryption claims revisited with their proprietary, patented “xAES” algorithm

I had asked last year about the encryption claims by the web service called https://unseen.is. The very same service that had claims of "beyond army level encryption", "4096 bit keys" etc. This is the ...
10
votes
2answers
492 views

What's the chance of two PGP keys being exactly identical?

In the real world, millions of PGP keys are created every day, what is the probability (chance) of creating two identical keys? In different places, by different people?
7
votes
2answers
423 views

Why standards organizations give so short protection times for 128 bit encryption?

According to this and this, seems even 128 bit encryption should remain secure for a much longer time than what security organizations say. I saw the standards with this: http://www.keylength.com/en/...
5
votes
2answers
4k views

Do you need more than 128-bit entropy?

UUID uses 128-bit numbers. Currently it is not feasible to randomly produce two UUIDs that are the same. Does that mean 128 bits of entropy is suitable for all cryptographic operations? I would ...
5
votes
2answers
3k views

Are RSA 2048, ECDSA, and the SHA uncrackable in the sense that AES-256 is uncrackable?

The answer https://security.stackexchange.com/a/25392 has seemingly shown that AES-256 will not be directly cracked for at least the next 200 years (unless we manage to harvest the energy output of ...
5
votes
2answers
2k views

Designing a cryptographic file-sharing protocol

As a learning project, I am trying to implement a secure way to share files with a friend over dropbox. (I am not looking for existing software, I am doing this in order to learn how to do this right.)...
4
votes
2answers
1k views

SSL Bit Length History

Sometimes I see web pages advertising a site's support for SSL with a given bit length (commonly 128), and saying that visitors need certain browsers that support this. Is 128-bit SSL common now, or ...
3
votes
2answers
734 views

What risk does commoditized dedicated SHA256 processors pose to IT Operations?

With the advent of GPU-based computing, and now commoditized/dedicated SHA256 processors, what risk does this hardware pose to cryptography? What security algorithms should be closely watched or ...
2
votes
2answers
3k views

How long would it take a single Processor with the AES-NI Instruction Set to bruteforce an AES Key?

I know that it seems like a stupid question - since it's note feasable to break AES without a quantum computer but I'm curious anyway. I read on wikipedia that the best known attack on AES-128 takes ...
1
vote
2answers
365 views

Are the Microsoft Windows images found on the internet safe?

Microsoft has stopped offering the Windows images for download. It is now only possible to get the image if one has a key of a retail version of the corresponding OS. The question is now, whether the ...
12
votes
1answer
16k views

Will double encryption increase the security of cipher vs bruteforce?

Assume I have a function encrypt(mes,key) where mes is the message, and key is the key. The length of key is 64 bits. Last but not least: assume the only way to crack my cipher is a brute-force attack....
11
votes
1answer
12k views

Why is secp521r1 no longer supported in Chrome, others?

Found a few issue threads, notably for Chrome (Chromium issue #478225), and the browser does appear to have dropped support for the secp521r1 curve (can test your browser using SSLLabs). There were ...
8
votes
1answer
8k views

PGP RSA key size - encryption/decryption time

From what I've read, PGP only uses the pub/priv keys for encrypting/decrypting a symmetric key used for actually encrypting/decrypting data. I'd reasonably assume that longer asymmetric keys wouldn't ...
6
votes
1answer
5k views

Security of bcrypt/sha256 key used with AES to encrypt a file

I'm looking to encrypt files using secure hashing and encryption algorithms in Python. Having used bcrypt in the past, I decided to use it for my passphrase calculator, then pass the output through ...
5
votes
1answer
8k views

Is there a maximum allowed key size in the USA?

I've heard that using encryption outside military use has been illegal for a long time in the USA. However, I've also heard that when the regulation was updated, limits were put on encryption strength ...
4
votes
1answer
348 views

Is there a PRNG in Java with a period of at least 256 bits?

From what I can tell, Sun JRE/JDK's are limited to only providing 128-bit strong cryptography without downloading an unlimited strength jurisdiction policy files. My question is, if I install theses ...
2
votes
1answer
193 views

Usefulness of bcrypt(UUIDv4())

One of my colleagues is working on securing OAuth 2 client IDs and secrets for our OAuth server and he has come up with this scheme where he would not only use UUID v4 to generate random values, but ...
1
vote
1answer
363 views

KeePassXC & Yubikey HMAC-SHA-1 vs 40+ Character Password

Looking at the implementation of the Yubikey 4 HMAC-SHA1 mode for KeePassXC, I want to know: Isn't the HMAC-SHA1 challenge response less secure than a 40+ character password? From what I know, the ...
1
vote
1answer
229 views

How long can a pkcs#8 passphrase be?

A program is using a private key to read messages. To improve security, besides randomness, I'm trying to create the longest passphrase that makes sense. How long should it be? After which amount of (...
1
vote
1answer
272 views

Does pppd encrypt traffic?

There is pppd program that can be used to create point-to-point conections over various channels (including other network). It supports authentication and compression. But does it encrypt traffic or ...
0
votes
1answer
239 views

PHP - Does password_hash/Argon2i effectively truncate passwords after certain length?

If I'm not wrong, by default PHP's password_hash with PASSWORD_ARGON2I outputs a 43-character alphanumeric hash among other things. While this means that simple passwords that are shorter than 43 ...
0
votes
1answer
908 views

Is there an AES 256 LUKS encryption option in Fedora? [closed]

I have certain information on my drive that I don't want anyone (not even me ;) ) to gain access to. I read recently that Fedora only offers EAS 256 LUKS encryption. This just isn't secure enough ...
-4
votes
1answer
99 views

Binary Numbers converted to Hexadecimal private key [closed]

Couldn't you use brute force to guess someone’s binary number because it's 1 or 0 - 256 times then just keep switching 1's and 0's around- which then can be converted hexadecimal to guess their ...
2
votes
0answers
85 views

How easily could a global network of machines break cryptography? [closed]

Suppose the NSA through legal means, or a malware group through illegal means has access to enormous computational resources via a backdoor into all Microsoft Windows machines (or some significant ...

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