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
480 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
422 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 ...

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