In reply to Pete Chown.

“Is a rand from /dev/urandom secure for a login key?”
http://stackoverflow.com/questions/31356466/is-pythons-random-number-generation-easily-reproducible

The short answer is yes. The long answer is also yes. /dev/urandom yields data which is indistinguishable from true randomness, given existing technology. Getting “better” randomness than what /dev/urandom provides is meaningless, unless you are using one of the few “information theoretic” cryptographic algorithm, which is not your case (you would know it).

The man page for urandom is somewhat misleading, arguably downright wrong, when it suggests that /dev/urandom may “run out of entropy” and /dev/random should be preferred; the only instant where /dev/urandom might imply a security issue due to low entropy is during the first moments of a fresh, automated OS install; if the machine booted up to a point where it has begun having some network activity then it has gathered enough physical randomness to provide randomness of high enough quality for all practical usages (I am talking about Linux here; on FreeBSD, that momentary instant of slight weakness does not occur at all). On the other hand, /dev/random has a tendency of blocking at inopportune times, leading to very real and irksome usability issues. Or, to say it in less words: use /dev/urandom and be happy; use /dev/random and be sorry.

(Edit: this Web page explains the differences between /dev/random and /dev/urandom quite clearly.)
http://www.2uo.de/myths-about-urandom/

See also
https://docs.python.org/2/library/random.html#random.SystemRandom
Warning The pseudo-random generators of this module should not be used for security purposes. Use os.urandom() or SystemRandom if you require a cryptographically secure pseudo-random number generator.

See also https://www.大肚孕妇2在线观看免费版高清.org/magpi/issues/

Lots of free PDF magazines plus special issues on various topics and project books.

Thanks.

There’s also https://www.大肚孕妇2在线观看免费版高清.org/learning/hardware-guide/ and https://www.大肚孕妇2在线观看免费版高清.org/learning/software-guide/

I’ve not read them myself, but there’s https://www.大肚孕妇2在线观看免费版高清.org/learning/sonic-pi-lessons/

I know the one time pad is just a learning exercise, but I think there is an inaccuracy in the description. The lesson claims that a OTP offers perfect secrecy, which is correct, but only if it is generated from a truly random source.

The lesson suggests using random.randint, which is bound to be insecure. The suggested alternative, os.urandom, reads cryptographically secure pseudo-random bytes. This is likely to be secure in practice but it won’t give the perfect secrecy mentioned in the description. Someone wanting that would need to read /dev/random.

By the way, I think it’s really good that these learning resources are easily available. People occasionally ask me how they can get started with programming (though no one has ever asked me about hardware or digital making). Is there a complete programming course I could point people to, or would I have to pick out individual lessons that would be appropriate to the their level of expertise?

All the links are in the blog post above – follow them, do them!

I just worked through the Shakespearian insult generator. This is really an EXCELLENT learning resource for people trying to learn about using Python! This was all the time I had for tonight, hope to get back to the web page one and encryption one in the next couple of nights.

For example, I can now use the skills I learned about parsing the columns when I collect data from say an Arduino in multiple columns when I want to plot the results that have been stored in a csv data file.

2 short questions I have for you.
1.) How do I move the button box down a line or two? A quick glance at the Guizero documentation you linked to did not make that obvious to me. I am sure it is simple, but no time to hunt or figure it out.
2.) Hoping I can get you to answer this one, so I am sneeking it in here. Need to be able to read files from USB thumb drives and main hard drive(s) using the X86 Pixel Raspian image. I REALLY like this and hope that you will continue the development of this. It really speeds up a bunch of my older PC’s that had become unusable with higher versions of Windows, and it has the same environment as my multiple RPi3’s. Very nice.
3.) PLEASE, PLEASE, PLEASE get SOMEONE SOON to update the Arduino IDE repository with the newest Arduino IDE now available for the Linux(ARM). The Arduino.cc website now has the latest version of the Arduino IDE for linux(ARM) processors. The extremely old v 1.0.5 in the RPi respository (even though it has a 2 before it for the ARM version from the repository, it is the old 1.05) is really/extremely dated, and does not support the Arduino DUE board for example. It also has error in the PulseIn timing function when one uploads the same code from newer PC versions of the Arduino IDE. I discovered this problem when making ultrasonic rangers, and running the same code uploaded from a PC IDE, vs. uploaded from the repository IDE. When the code is uploaded from the PC IDE, the serial monitor gives correct results when read from either the PC or RPi3. When the code to the Arduino is uploaded from the RPi repository Arduino IDE, it gives the wrong results (off by about 30% as I recall), when read on the serial monitor of both PC and Rpi IDE’s. Thus it is clearly a problem with the function from the (very old) Arduino IDE that is in the repository. Please get this updated ASAP. We need to be able to use the most recent Arduino IDE on the RPI’s, and I don’t want to do an install without using the repository, for fear of screwing up some dependencies.

Many thanks, keep up all the good work you are doing!!

No I have not built anything from your resources, but I am very interested in everything 很黄很黄的高潮口述 PI has to offer and want to learn as much as I can from the ground up. Please let me know how I can start learning how to utilize and create resources from a beginner level.