identity – Identification through digital signature. How safe is it?

Let’s say I want to give some data to Bob. I have his public key. I tell him to generate a digital signature for text “{some_stuff: 1, nonce: 2}”. After he does that and after I verify it’s the right signature, I give him the data. I use a different nonce for each session. Is there anything I need to be aware of? Is it pretty secure?

authentication – Craigslist type site for domain/website asks for my selfie with identification card – Unsafe?

Flippa is a website that lets sellers of domains and website list their properties for sale.
They do not handle funds, escrow d0t com and/or paypal handles the sales.
After taking my money for listing (250) I was able to sell my website.
When it came to finish sale, told me that in order to proceed to escrow d0t com that I must:
Upload selfie with my govt id, scan both sides of id, AND also do a “liveness video.”
I was a bit alarmed and looked in the their partner.
They use a company that does KYC verification. Find it strange flippa, a non-financial company, is using KYC.
Anyway the company they use claims to be based out of London.
Which is is not true, their address in London is paid virtual business office.
They are a Russian company, with russian founders and employees.
No hate on Russia but as an American I am not comfortable uploading all this private info JUST to complete a website sale!

Is this even legal for Flippa to do?
Flippa also says they store the information I sent them.
I don’t like that they only ask me to complete this AFTER they have my money.

A company that offers listing service for domains wants my selfie with my govt id. They use verification service that obscures that they’re based in Russia. Is this safe?

I wander somewhen treated face identification?

Does anyone by chance had the use of face detection using Buxtank ?

proof explanation – How to prove that the induced topology is the coarsest and identification topology is the finest topology that keeps the map continuous?

I am reading maps between topological space from Isham, Chris J. Modern differential geometry for physicists. Vol. 61. World Scientific, 1999.. Here he defines the induced topology and the identification topology in the following way

If $(Y,tau)$ is a topological space and $f$ is a map from $X$ to $Y$
then the induced topology on $X$ is defined to be $$
f^{-1}(tau):={f^{-1}(O)|O in tau} $$
The key property of the
induced topology is that it is the coarsest topology such that $f$ is

Another important example arises when $(Y,tau)$ is a topological
space and there is a surjective map $p: Y to X$. The identification
topology on $X$ is defined as
p(tau) := {Asubset X | p^{-1}(A) in tau}
The key property of this topology is that it is the
finest one on $X$ such that $p$ is continuous.

I want to prove that

  • the induced topology is such that $f$ is continuous
  • the identification topology is the finest topology such that $p$ is continuous

I know that a map $f:(W,tau) to (V,tau’)$ is a continuous map if for all $O intau’, f^{-1}(O) in tau$.

I also know that in general, any maps between two sets ($f:Ato B$) have the property
f^{-1}(Acap B) = f(A) cap f(B) \
f^{-1}(A cup B) = f(A) cup f(B)

This comes handy to prove that both of the induced and identification topologies are topologies.

But I don’t know where to start with the proofs.

canada – Canadian places identification

I’ve recently came across a post claiming that the following images are taken in Canada. A quick Google search told me that the first image is Spirit Island and the last is Moraine Lake. Third image was once (further images reuploads failed) identified as
Cass Scenic Railroad State Park. Are those accurate findings? These places look gorgeous.

Spirit Island (identified by Google, map location):

Spirit Island

Moraine Lake (identified by Google, map location):

Moraine Lake

Cass Scenic Railroad State Park (identified by Google, map location, but not of exactly this place):

Cass Scenic Railroad State Park

Google failed to identify these two images:

enter image description here

enter image description here

Can someone confirm or otherwise name the locations?

python – Identification of Peaks from a Line Graph

The first script produces a line graph using signal output data. My next step was to identify the peaks present on the line graph. The second script has an algorithm to identify all the peaks present on the line graph. However it is too sensitive. It classifies even the slightest bumps on the graph as a peak. I do not want this. I only wish to identify the conspicous(large) bumps as peaks. How do I modify the second script to do this?Line Graph

import matplotlib.pyplot as plt
import numpy as np

X, Y = (), ()
X = np.zeros((10, 4096))
Y = np.zeros((10, 4096))

for line in open('data_set2.txt', 'r'):
  values = (float(s) for s in line.split())
  X(n,0) = values(0)-1566518691968
  for m in range(4096):


b = (X(1:)-X(:-1))(:-1)
c = (X(:-1)-X(1:))(1:)
minima = np.where(np.bitwise_and(b<0, c<0))(0)+1
maxima = np.where(np.bitwise_and(b>0, c>0))(0)+1
all_peaks = np.where((b*c)>0)(0)+1
del b,c


product identification – What is the name of this post apocalyptic setting?

There is a post apocalyptic setting that I’ve always wanted to play/GM and finally found a group for but I can not find the system anymore.

Here is what I remember.


Scene Based

Free online PDF

Modern and slightly beyond tech but more about salvage then inventing.

I think they used slightly modified stats, 4 core stats with one begin something like “Gutz”

Low magic. Whatever caused the apocalyptic caused a rift that allowed magic. But mostly it was like mind reading psychic type with some healing ect.

Many classes revolved around access to items/equipment that would be rare. Medic might have a small makeshift lab. Mechanic might have a small workshop with some tools. Occult leader would have their followers and maybe a base. Mob leader might have a base. Bike gang leader might have a small group of NPC bikers.

product identification – RPG with Rats as PCs?

I am tryting to remember what the name of that (german?) RPG was where you play a rat in some sort of decrepit house or mall or something. One of the worst enemies would be Cats.

I remember that it used a rather simple mechanic of just d6, some keywords on each chacarter and some… checkboxes I believe.

Rats were of different breeds (tribes?) and one of them were labrats.

equipment identification – What gear does Robbie Lawrence use?

I’m wondering if someone could recognize which kind of camera Robbie Lawrence uses.

I think his image could have been shot with an analogue camera, but I’m not really sure because a lot of people use digital cameras and recreate the analog touch in post production.

product identification – Which superhero RPG system is this quote about?

Many years ago, someone shared the following anecdote about a superhero RPG system. (I’ve paraphrased considerably since I don’t remember the exact text.)

“Attempts to do weird things to a character, like polymorph them or glue them to a building or send them to the Dream Realms, are modeled using damage. Your turn-into-a-frog power might deal ‘frog damage’, and if a character takes more frog damage than their current hit points, they get turned into a frog. The rationale is that using a debilitating effect on a character should be approximately as difficult as defeating them.”

We’ve had some questions recently about “called shots” in D&D contexts, and the existing called-shot systems don’t seem very good, so I was thinking it would be interesting to understand more about how this superhero RPG system worked.

What system was this?