I am trying to understand how a cryptographic library works (for example, one that provides assymetric encryption such as RSA), but I'm running into a few problems about the key-generation. There are a lot of questions regarding the generation of random primes, but I'm interested in the generation of a random number. There seem to be some official guidelines by the government (for example, NIST FIPS 186-4 (PDF) is referred to in a couple of other answers to questions about random prime generation) for the generation of keys for certain protocols, but they are not an easy read and I don't think they answer my questions.

I think I understand the basic principles: Entropy is gathered by the operating system or a daemon to provided a small amount of unpredictable data that is used as a seed for a cryptographically secure pseudo-random number generator (CSPRNG). The CSPRNG generates the random numbers that are used to generate random primes (either a probable or provable prime).

What is a good CSPRNG? I couldn't find the algorithm that OpenSSL uses (it's very well possible that there are multiple). Wikipedia lists a bunch, but doesn't provide sufficient information on implementation and performance.

Also, are there any additional constraints on the prime or prime pair that is generated? I vaguely remember reading something about prime products of a certain form that are no good for use in cryptographic keys (because they are easy to factor with some tricks).

Mental burnout - or mental exhaustion is not very pleasant, when one feels completely overwhelmed, something 'snaps' and it is hard to concentrate and maintain motivation. What are the cognitive processes that occur during a burnout? What processes allow for recovery?

I was surprised to see in advertisements for "miracle" natural / alternative / herbal etc. medicine that they contain "liquid chlorophyll" and that is really useful for our health.

I wondered how it can be, because chlorophyll is actually what plants use for photosynthesis, so humans could make absolutely no use of it. Even if our whole skin could photosynthesize, it would provide only a small fraction of the required energy. By the way, absolutely any plant we eat contains chlorophyll, so why would anyone not eating exclusively meat require additional chlorophyll, even if it was useful?

The Wikipedia article shows absolutely nothing about any medical uses of chlorophyll. A Google search for chlorophyll and "medical uses", "health benefits", etc. returned only sites belonging to companies actively selling it, and describing it as a miraculous cure-all. I did not manage to find any independent or independent-seeming article about the subject.

What are the pros and cons of each bottle sanitizing method? Let's look at time, equipment, quality of sanitation, and other factors.

Post one answer for each method. Edit the answers if you have things to say about that method. (Community Wiki)

Example would be:

Boiling

Process

How you boil bottles

Equipment

What's needed for this method

Effectiveness

How effective is this method

Other Pros

Other Cons

{brewpoll}

I have a raspberry pi model b+ that I am attempting to boot with a root on an nfs share. The pi takes an ip address from dhcp, and makes request to my nfs server for the root share. The server reports this request in logs, but the pi hangs after printing its ip configuration. The last cmdline.txt I tried contained: root=/dev/nfs rw nfsroot=192.168.2.25:/srv/rpi-root-nfs,tcp ip=dhcp vers=3

/etc/exports on the nfs server contains: /srv/rpi-root-nfs 192.168.2.0/24(rw,sync,no_root_squash,no_all_squash,insecure)

Are there any problems with this configuration?

UPDATE (06-06-2016) -- took a picture of the boot logs with loglevel set to 7. The line [ 7.318013 ] ... rootpath= is odd, as rootpath should be set, according to the kernel line.

7.318013 rootpath is not set

Необходимо по событию on_change на поле Name сохранить создаваемую запись в базу и остаться в форме редактирования записи (см. рис. ниже)

Форма в режиме создания записи Форма создания записи до сохранения

А вот такую форму необходимо получить после отработки события on_change:

Форма после создания/сохранения записи в режиме редактирования

Обратите внимание, что форма находится в режиме редактирования, но системное поле идентификатора id инициализирована и в таблице уже существует запись.

Код (который создает запись при изменении поля Name, но это не решает проблему, т.к. при нажатии на кнопку Create создается еще одна запись):

from openerp import models, fields, api

class Master(models.Model):
    _name = 'att.master'

    name = fields.Char("Name")
    qty = fields.Integer("Qty")

    @api.onchange('name')
    def _on_change_name(self):
        if self.name:
            self.qty += 100
            print 'The on_change event was happened'
            self.env['att.master'].create({'name': self.name, 'qty': self.qty} )

View:

<?xml version="1.0" encoding="UTF-8"?>
 <openerp>
    <data>
        <!-- form AGREEMENT -->
        <record model="ir.ui.view" id="att_master_view_form">
            <field name="name">Master</field>
            <field name="model">att.master</field>
            <field name="arch" type="xml">
            <form string="Master">
                    <sheet>
                        <group colspan="4">
                                <field name="name"/>
                                <field name="qty"/>
                                <field name="id"/>
                        </group>
                    </sheet>
            </form>
            </field>
        </record>

        <record model="ir.ui.view" id="att_master_view_tree">
            <field name="name">List of master</field>
            <field name="model">att.master</field>
            <field name="arch" type="xml">
                <tree string="List of master">
                    <field name="name"/>
                    <field name="qty"/>
                    <field name="id"/>
                </tree>
            </field>
        </record>

        <!-- window action -->
        <record model="ir.actions.act_window" id="att_master_list_action">
            <field name="name">Master</field>
            <field name="res_model">att.master</field>
            <field name="view_mode">tree,form</field>
        </record>

        <menuitem id="att_master_menuitem" name="Master"
                  parent="att_menu_agreement"
                  action="att_master_list_action"/>
    </data>
</openerp>

As a kid, I was an avid swimmer. I was nowhere near an expert, but I was in a pool, swimming laps, almost every day of the summer. My form was probably poor then, but nobody instructed me otherwise.

As a "pushing-40" adult, I'd like to get back into swimming, potentially training for a triathlon (haven't hit the bikes yet). I know my form is poor and want to get better. What are resources, exercises, methods that the SE community can recommend to get me (re)started?

TIA, Larry

I'm looking for techniques specific to a story with an unsympathetic main character. Confederacy of Dunces, for example. Why does that work, and why wouldn't that work with a likable hero?

You’ve never seen such a verdant shade of green as the leafy tops of the trees that now form a focal point up ahead, peaking over the high and solid concrete walls which surround Eden. The colour makes you uneasy, so you focus on the grey of the wall instead. Intellectually, you’re well aware that the leaves look like leaves are supposed to, unpoisoned, but it feels like you’re halluncinating after watching a particularly pristine old movie disc.

Set into the middle of the wall is an enormous metal door, polished and gleaming in the sunlight. The door sits adjacent to the termination of the dirt path leading up to itself, a symbol of Eden’s rejection of the outside world.

Your stomach is queasy with nerves as you come closer and closer to the door. You’ve never heard of anyone who’s successfully gotten into Eden from the outside world, or come out of Eden. You’ve never even heard of someone who’s tried and failed. Your eyes dart around the imposing surface of the wall, searching for turrets.

Though your steps grow ever shorter as you approach, you soon find yourself within knocking distance of the great metal door. You wrap a rag around your hand so as not to touch its hot surface and wrap your knuckles against the door three times.

Before you’ve even completed your final knock, a voice booms down from on-high.

“ONLY THOSE MAY ENTER WHO POSSESS THE KNOWLEDGE OF GOOD AND EVIL.”

You chuckle inwardly at the irony. “I have this knowledge,” you shout back to the voice.

“LET THE ONE WHO HAS THE KNOWLEDGE REPEAT THE PASSPHRASE FROM WHICH THE KNOWLEDGE DERIVES.”

You consider for a moment. “apple”

“INCORRECT. THREE ATTEMPTS REMAINING.”

“Apple123”

“INCORRECT. TWO ATTEMPTS REMAINING.”

“Apple123!”

“INCORRECT. ONE ATTEMPT REMAINING.”

Okay, it’s probably not going to be that easy.

“AND ON THE FOURTH FAILED ATTEMPT, THE TREE OF LIFE WAS REMOVED FROM THE UNWISE ONE.”

Right, better not waste that one. You survey your surroundings, in search of anything that might help you figure out the password. There’s not very much around that could possibly help you, but just as you’re about to give up hope, you see a very conspicuous red-coloured rock lying on the ground just next to the enormous door. A grimy slip of white juts out from underneath the rock.

You lift the rock and discover a folded piece of paper. Unfolding it, you discover a set of cryptic lines, written in small, neat handwriting.

OIOOb
_IOI0
OI_If
IOOO6
_OOO8
I_II9
II__3
_IOO1
O__I2
OIOI9
OOOOa
_III8
IOI_f
OO_Of
OIIIe
_OIO0
OOIOb
_IO_1
_IIO4
IO_Oe
OIO_d
__IOc
IIOIe
O_OO4
IIIId
IOIO9
IOOI8
IO_Ic
IO_I0
IIIO8
OO_I5
OOII8

So do as the title suggests if you can. Even if you cannot solve it, still all kinds of ideas are welcome.

The language is English. The title may include some clue; it is the original phrase of the puzzle.

Is the Polar Satellite Launch Vehicle capable of taking a 1,350 kg orbiter from the Earth to Mars as this article states?