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In computing, entropy is the randomness collected by an operating system or application for use in cryptography or other uses that require random data. This randomness is often collected from hardware sources, either pre-existing ones such as mouse movements or specially provided randomness ...

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1answer
103 views

For a “normal” computer user, does it make a difference to have a good entropy source?

Let's take, for example, Linux. From my understanding, there are different sources and different ways that can be used to gather entropy (RNG daemon, Intel rrandr, TPM, etc). Some produce entropy that ...
87
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4answers
10k views

Chrome generated passwords not high entropy?

On Chrome, if you open a sign up page, it will offer to fill and remember the password field. I did this and got the following sequence of passwords offered as generated: suCipAytAyswed0 ...
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1answer
137 views

Why would Bill Burr of NIST say N3v$r M1^d?

Wall Street Journal wrote that Bill regrets his password recommendations NIST SP 800-63 Appendix A. Apprendix A is titled "Estimating Password Entropy and Strength". It is about how we might assess ...
0
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1answer
134 views

How can an Android device be unlocked, and how long would that take?

The original question was about the minimum password (or PIN) length (or entropy) for the screen lock in Android. Seeing that nobody answered, and following Schroeder's advice, I'm going to edit it ...
0
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1answer
149 views

Calculating Entropy using md5sum, sha256sum etc

We can calculate the Entropy S of a string simply like this: S = L * log_2(N) Where L stands for used characters in the string And N for every possible character Example: We want to calculate the ...
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1answer
186 views

Would `cat /dev/random` be a denial of service to any other users of `/dev/random`?

As in the question. Wouldn't cat /dev/random decrease the entropy estimate until it blocks, which forces the random device to block for all applications on the current system?
0
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1answer
37 views

How much entropy is required for a Grid Card?

We're in the process of implementing multifactor authentification. One good candidate for this was the "Grid Card" - a small table with random letters and digits. Upon login, the user would be queried ...
14
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2answers
755 views

Is “always use /dev/urandom” still good advice in an age of containers and isolation?

In short: Instead of another question asking about when to use /dev/random instead of /dev/urandom, I present the following scenario, in which I find myself in an application I'm building: A VM or ...
2
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1answer
172 views

Injecting data into the Windows entropy pool

On Linux, it is possible for userspace to mix arbitrary data with the kernel entropy pool by writing to the /dev/urandom device. Is there any equivalent on Windows which does not require SYSTEM?
9
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1answer
111 views

Random seed not propagating to the entropy pools in a timely manner

The Linux kernel's randomness driver collects entropy from the environment. Because there will be little entropy during boot, a random seed is often kept at /var/lib/misc/random-seed or a similar ...
3
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0answers
154 views

Entropy sources used by modern Windows

A comment on a Microsoft blog from 2005 mentions over 150 sources of entropy for the Windows CryptGenRandom function. The majority of sources come from low-level system information (precise stat ...
3
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1answer
95 views

Linux 'add_interrupt_randomness' implementation - low entropy contribution by cycles and jiffies?

Currently I'm analyzing the process of entropy generation of a Linux 64-bit kernel during system startup (for educational purpose). The system is hosted as/on a (64 bit) virtual machine (Xen domU). ...
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1answer
225 views

How to convert zxcvbn entropy to score

I want to use zxcvbn-c but it gives the entropy number, not score like the javascript library does. How do I convert entropy number to a score? (0 to 4) The zxcvbn blog/source mentions that the score ...
0
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0answers
130 views

How secure is BouncyCastle's SecureRandom .NET(C#) class?

I've already seen some question related to this, but the most upvoted answer just states that SecureRandom is not DumbRandom basically (yes, it doesn't use DateTime.Now.Ticks as its seed, of course). ...
1
vote
1answer
281 views

What is the benefit with passwords that are always 50% numbers and 50% letters?

In Teamviewer, I am using "secure (8 characters)" passwords that are changed daily. I noticed that the password is always 4 numbers and 4 lower case letters, with random positions. I might be naive, ...
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1answer
206 views

Password entropy boosting [closed]

Can the process of generating a password based on the transformation of random 3D data into a 2D data chain have better entropy than other methods of generating 2D random data chains?
5
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1answer
1k views

Passphrase vs. password entropy

For a while now I have been interested in the passphrase concept as a potentially more secure replacement for classical passwords. My interest stemmed from a gut feeling that passphrases would be of a ...
4
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2answers
257 views

Entropy on native memorable password on macosX keychain

I have been trying to find information on this. But I haven't found anything online. When you use the password manager on mac, it can provide "memorable" passwords. For example pick3"enigma. (You ...
2
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1answer
142 views

Are encrypted files safe in Windows 10 when using PINs?

In Secrets and Lies, Bruce Schneier writes: Many keys are generated from passwords or passphrases. A system that accepts 10-character ASCII passwords might require 80 bits to represent, but has ...
6
votes
4answers
297 views

multiple dice ware lists to make memorable passphrases?

I understand the basics of why diceware produces good security and why seven word passphrases are a good idea these days. The EFF has helpfully produced updated diceware lists that eliminate lots of ...
29
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7answers
5k views

How was the concept of password entropy developed?

I understand how to calculate password entropy and what the Length and Character values represent. I also have a reasonable understanding of other types of entropy (e.g. Shannon). However, password ...
1
vote
2answers
218 views

Check the “security” of a password [closed]

I'm trying to find a tool to validate the security of a password and I've come across cracklib or libcrack2 (on Debian), which seems to be used a lot for the task and appears to do exactly what I ...
2
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0answers
116 views

Approximately how much entropy in each of these low entropy sources?

We need a lot of entropy. Let's be a little unrealistic and assume that we don't have access to entropy pools like dev/random, and must do all the entropy collection ourselves. The program is running ...
1
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2answers
198 views

On an embedded system with no external input, can haveged provide entropy?

Take an example embedded system: Microprocessor Flash memory SDRAM There is no UI and no network connection. Can the CPU timing jitter that is used by haveged provide adequate true entropy to seed /...
2
votes
1answer
87 views

How to determine how entropy changes when using uppercase, numbers and special characters in a dictionary based passphrase?

I know the general math behind using character-based and dictionary-based passwords/passphrases and how to determine the entropy of the result. But I am unclear how adding uppercase letters, numbers ...
57
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4answers
11k views

Expert quote on entropy for uncrackable password

Could anyone point to a quote in a published work - or suggest a recognised expert who might provide a quote - which answers the following question How much entropy in a password would guarantee ...
1
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2answers
941 views

How does the password Tr0ub4dor&3 have ~28 bits of entropy? [duplicate]

I rencently seen this : I can't figure out, how he computes 28 bits of entropy for a password like "Tr0ub4dor&3" seems really few...
4
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2answers
192 views

Research about entropy of human randomness?

An argument people often use in favor of password managers is: Human-generated passwords have less entropy than randomly generated ones! Is there any research to back this up? Can we quantify it? ...
3
votes
4answers
632 views

Should I vary the length of my completely-random passwords for the best security?

I use LastPass comprehensively, and for each new site/password I almost always have it generate a random password of the same number of characters, allowing letters, numbers, and symbols (except when ...
2
votes
1answer
96 views

Should Longer Random Data Have More or Less Entropy?

I have been making a random number generator using an Arudino's analog pins, bitwise shifts, and XOR. I have been using the Unix command 'ent' to measure my entropy. I have tested different sizes of ...
1
vote
1answer
144 views

Does entropy apply to passwords generation when some passwords are more likely? [duplicate]

Entropy is a standard measure of the complexity of a password generation. The standard way to calculate entropy is to take the probability p of a password being generated and take the sum of p*log2(p) ...
1
vote
1answer
103 views

Is this password entropy calculation correct?

I'm trying to compute the entropy of a passphrase of the following pattern: .... .... .... .... Where . represent lowercase characters. The passphrase follows the rule that the two parts of each 4-...
0
votes
1answer
204 views

BCrypt hash as database table ID

In my web application I have to store hashed values (using BCrypt) as ID for a database table. The input for each hash value is a unique string. I am concerned about possible collisions. 1) What is a ...
3
votes
1answer
220 views

GETRANDOM syscall's relation to kernel entropy pool state

I get that when GETRANDOM is called with bitmask 00, the entropy source is from /dev/urandom, and the CSPRNG output is blocking until internal entropy pool has at least 128 bits of entropy. Is the ...
1
vote
2answers
103 views

Do dynamic certificates for SSL-Interception pose a security risk due to weak entropy?

When you think about typical SSL-Interception in Firewalls, depending on the number of TLS-Connections, loads of Certificates get faked "on the fly" in a very time critical environment. In my ...
0
votes
2answers
287 views

Can Haveged help increasing entropy and make PRNG unpredictable (close to TRNG) on embedded Linux based headless device?

We have OpenSSL on BealgboneBlack Based Embedded Linux custom board and we were thinking about increasing randomness of PRNG(/dev/urandom). While browsing about it, I landed on this page: How to ...
3
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3answers
240 views

Use USB TRNG as source of randomness for OpenSSL key generation

I have an idquantique TRNG (USB). On my Debian machine, I can easily create a file on my disk coming from that TRNG filled with some random content. Is it possible to make OpenSSL and GnuPG (for key ...
3
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1answer
253 views

Algorithm used in grid card authentication

I have seen banks using grid card authentication after primary password based login. However, I am unable to find sufficient detail as to how it is being used. Is the challenge truly random or pseudo ...
113
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15answers
22k views

When choosing a numeric PIN, does it help or hurt to make each digit unique?

Imagine a typical 4-digit PIN scheme containing the digits [0-9]. If I choose my PIN at random, I will get one out of 10 * 10 * 10 * 10 = 10,000 codes. Based on my own experience, more than half of ...
4
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3answers
600 views

How secure is this method of password generation?

Introduction: I used to use the same password for everything (it was at least a really random password with fake words). Then I found out that I should have different passwords for different sites ...
9
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1answer
121 views

On the Use of Deltas in Linux Entropy Estimators

Recently, I've become interested in applied cryptography and stumbled upon a link explaining how Linux estimates entropy. At some point, we're told that entropy estimation is based on first, second ...
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votes
1answer
353 views

Why is WPA/WPA2-personal Entropy different?

Why is WPA/WPA2-personal passphrase entropy different than other entropy measurements? Is this because of the way WPA/WPA2 is implemented? For example: A passphrase of 15 lowercase letters has an ...
0
votes
1answer
181 views

Calculating entropy of a graphical password (Passface)?

I feel like I'm overthinking this as the only online example I've come across is this paper, which is using more advanced math than is expected of us. But if we have a known passface database off 100 ...
2
votes
1answer
168 views

How do SED drives generate the DEK?

Some newer hard drives and solid state drives are SED (Self-Encrypting Drives), which create a DEK (Data Encryption Key) and store it either unencrypted, or encrypted with a user-supplied AK (...
4
votes
3answers
2k views

Why are passwords with special characters considered more secure than longer length passwords? [duplicate]

For example, OWASP considers 10-128 characters, with lower, upper, digit, and special characters (I don't get why there's an upper limit). Using the OWASP's minimum guidelines and assuming there are ...
4
votes
3answers
335 views

Is it more secure to limit passwords that have two identical characters in a row?

OWASP recommends this practice and so do some other companies. I think it makes sense at first glance but if you think about it, it actually limits entropy instead of increasing it. How many ...
0
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1answer
121 views

Increase entropy by making passphrase more complex [duplicate]

I have just started reading on the use of passphrase to increase a password entropy and have gained a rough understanding of it. However, I'm wondering if it's possible to further increase the entropy ...
29
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4answers
8k views

Is randomly generating passwords from an assortment of dictionary words cryptographically secure? [duplicate]

We should all know the XKCD comic on password strength, suggesting (appropriately) that a password based on multiple common words is more secure and memorable than a password such as Aw3s0m3s4u(3 or ...
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0answers
157 views

Digest algorithm for the PRNG in OpenVPN

Considering the following OpenVPN (2.4) option from the manual: --prng alg [nsl] (Advanced) For PRNG (Pseudo-random number generator), use digest algorithm alg (default=sha1), and set nsl (default=16)...
3
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2answers
157 views

Is CAPTCHA enough to prevent attackers from draining entropy pool?

I'm working on a website which necessitates the use of server generated codes, which are displayed once to the user and then stored in a database. I plan on using /dev/urandom as a source of entropy ...