2019 Newsletter: 55/66 — PreviousNext — (Attach.)

Sydney Harbour

Hello and Welcome,

Meeting This Week:

Penrith Group - Saturday Nov 2nd - 2:00 pm - 5:00 pm

The meeting normally starts with a Q&A session around the table to enable members to share problems, advice and computer tips.

The group will then discuss any further technology or computer topics of interest.

Meetings Next Week:

Friday Forum - Friday Nov 8th - 9:30 am (10:00 am meeting start) - 12 noon
Communications - Friday Nov 8th - 1:00 pm - 3:00 pm

Current & Upcoming Meetings:

79 2019/11/02 - 14:00-17:00 - 02 Nov, Saturday - Penrith Group
80 2019/11/08 - 09:30-12:30 - 08 Nov, Friday - Friday Forum
81 2019/11/08 - 12:30-15:30 - 08 Nov, Friday - Communications
82 2019/11/12 - 17:30-20:30 - 12 Nov, Tuesday - Programming
83 2019/11/16 - 13:30-16:30 - 16 Nov, Saturday - Web Design
84 2019/11/19 - 09:30-12:30 - 19 Nov, Tuesday - Tuesday Forum
85 2019/11/22 - 09:30-12:30 - 22 Nov, Friday - Digital Photography
86 2019/11/26 - 17:30-20:30 - 26 Nov, Tuesday - Main Meeting


Tech News:

“Check out the new 4 GB Raspberry Pi 4”:

The new Raspberry Pi 4 is amazing. It has 4 GB of main memory, 4 cores each running at 1.75 GHz, inbuilt Wi-Fi and Bluetooth and it can output to two 4K monitors simultaneously.

I ordered a 4 GB Raspberry Pi 4, a Raspberry Pi 4 power supply and a Micro to Normal HDMI cable. Naturally they came in two packages a week apart! Thanks, Element**.

Apparently, third-party power supplies (or at least the USB-C connectors) have problems with power delivery. Power is there, but the RPi doesn't recognize it (whoops!). (So, don't try an Apple power cable).

It runs Raspbian, a variant of Debian Linux, and looks very colourful.

Browsers Chromium and Firefox ESR (Chrome and Firefox) run very well, displaying videos perfectly.

That is, unless you want to watch iview. The ABC uses a proprietary video format to show their own content which only runs on Desktop or Mobile devices using Chrome, Firefox and a few other browsers. Unfortunately, Chromium and Firefox ESR are not among them.

The Raspberry Pi 4 menu
The Raspberry Pi 4 menu.

This shows the (6) tabbed command line
The RPi 4 running four cpu-intensive programs in the command line tabs at 100% (and at 87°C).

This shows that the ABC iview does not work on the Raspberry Pi 4
Chromium and Firefox ESR do not work with iview's proprietary video format on the RPi 4.
Note the icons for the Windows 7 disk drives C: and D: on the Desktop.

The Raspberry Pi 4 cannot display iview videos
Kumi Taguchi explains in a perfectly watchable YouTube video why iview does not work on the RPi 4.

So, give the Raspberry Pi 4 a go.


“Samsung Fingerprint Scanner Has Major Flaw”:

See the Infopackets article by John Lister on October, 22 2019 at 02:10PM EDT.

Samsung has issued a security fix after revelations of a major flaw in its fingerprint sensor. It affects users who have added a silicone screen protector.

The fix came after a British woman contacted a newspaper to report that not only could she unlock her phone with the "wrong" fingerprint, but her husband could also unlock it with his finger. That's a major problem as she was using a Galaxy S10, a high-end Samsung phone that lets users set up fingerprint recognition not only to unlock the phone, but also to login to apps and even authorize mobile payments. (Source: bbc.co.uk)

Scan Misreads Surface as Fingerprint

The same problem appears to affect the Galaxy S10, S10+, S10 5G phones, along with the Note 10 and Note 10+.

The common factor is that they have a three-dimensional ultrasonic fingerprint scanner built into the screen itself, rather than a physical scanner beneath the screen or on the back of the phone. Having the fingerprint reader inside the screen (rather than a button somewhere on the phone) means manufacturers can produce a larger display without also increasing the overall size of the handset.

The problem is that the ultrasonic scanner is still set up on the assumption that the relevant section of the screen will be in direct contact with the fingerprint when it's first set up. However, if the user has a screen protector on, the sensor is actually recording information about the underneath of the screen protector, including any bubbles or debris that may have been caught under the screen protector when it was first applied.

That's a security disaster as when the fingerprint authorization is next used, the 'scan' will read the same on every check regardless of whose fingerprint is actually in position.

Samsung: Remove Screen Protector Now

Samsung's taking a two-pronged approach to the problem. Firstly, it's issued a security update that will change the scanning process: the idea being that if a screen protector is present, it won't accept the initial scan as valid.

Secondly, it's urged all users to remove screen protectors, delete any stored fingerprints, and re-register their fingerprint to get an accurate and usable reading. (Source: express.co.uk)

Read more »

“VPN provider NordVPN suffers breach through third-party data centre”:

See the iTWire article by Sam Varghese | Tuesday, 22 October 2019 10:09.

Virtual private network provider NordVPN has suffered an embarrassment, with one of the data centres in Finland it was using having been infiltrated in March 2018 through what it said was "an insecure remote management system".

An unidentified security researcher pointed to the breach, indicating that an expired private key had been exposed, meaning that someone else could masquerade as NordVPN.

Another unidentified researcher tweeted that two other VPN providers, VikingVPN and TorGuard — which have no connection to the Tor browser — had also been compromised.

In a blog post on Monday, the company's blog editor Daniel Markuson did not name the data centre provider in Finland.

NordVPN does not keep logs and therefore could not ascertain the credentials that had been used to gain entry.

"The server itself did not contain any user activity logs; none of our applications send user-created credentials for authentication, so usernames and passwords couldn't have been intercepted either," Markuson said.

"The exact configuration file found on the Internet by security researchers ceased to exist on 5 March 2018. This was an isolated case, and no other data centre providers we use have been affected."

Markuson said the data centre operator had noticed the vulnerability and had deleted the remote management account but had not informed NordVPN about it.

"The expired TLS key was taken at the same time the data centre was exploited," he said.

"We failed by contracting an unreliable server provider and should have done better to ensure the security of our customers."

Read more »

“Affordability Report — Alliance for Affordable Internet”:

Referred by Roger Foulds: See the Affordability Report produced by the Alliance for Affordable Internet.

A global coalition working to make broadband affordable for all

Welcome to the Affordability Report — an in-depth annual research initiative produced by the Alliance for Affordable Internet. The report represents part of our ongoing efforts to measure policy progress toward affordable internet.

The 2019 Affordability Report, released in October 2019, points to a lack of competition in broadband markets as a major barrier to affordable access — and explores how governments can shape healthy, competitive markets supported by public access solutions to deliver affordable and meaningful connectivity for all.

Read the 2019 Affordability Report — Online | Download as PDF

Press Release

Executive Summary

Impact Stories — Read about the human impact of the policy issues in the report in Indonesia, Cameroon, Mexico, Nigeria, and South Africa.

Read more »

Fun Facts:

“Final details on The Square == Triangle Number Problem”:

As we said last time, we can reduce this problem to the Pell equation, x2 - 2y2 = 1.

The solutions come from the continued fraction for √2 which is [1;2,2,2,2,2,...] and that leads to a recurrence relation for the sequence of values of x and y.

Now, the x solutions start as 1 and 1 and then we use the formula: xn+1 = 2xn + xn-1 which produces the list: 1, 1, 3, 7, 17, 41, 99, 239, 577, 1393, 3363, ...

Similarly, the y solutions start with 0 and 1 and, using the same formula, we get the list: 0, 1, 2, 5, 12, 29, 70, 169, 408, 985, 2378, ...

However, the numbers we want are related to every 2nd pair of numbers. One pair solves x2 - 2y2 = 1 and the next solves x2 - 2y2 = -1.

This changes the recurrence relation to xn+1 = 6xn - xn-1 which comes from some Algebra — squaring the relation: x2 = 2x + 1 gives x4 = 6x2 - 1.

The new x and y gives the list: x = 1, 3, 17, 99, 577, 3363, 19601, 114243, 665857, ... (every second number).

And the other list: y = 0, 2, 12, 70, 408, 2378, 13860, 80782, 470832, ... (also every second number).

Nearly there...

The square numbers we need are from the y list, and they just need to be halved.

The triangular numbers are from the x list, and here we just need to subtract 1 and halve the number.

As an example, take the matching pair (x, y) = (577, 408) — From y = 408, we get the square number we want as 204 and the triangle number we want is (577 - 1)/2 or 288.

Just checking: 204×204 = 41616; and the triangle number is 288×289/2 = 41616 which is a match!

The final simplification (halving and subtracting 1 and halving the other solution) modifies the two lists:


x0 = 0, x1 = 1 and recurrence relation: xn+1 = 6xn - xn-1 + 2

y0 = 0, y1 = 1 and recurrence relation: yn+1 = 6yn - yn-1

x = 0, 1, 8, 49, 288, 1681, 9800, 57121, 332928, 1940499, 11309768, 65918161 ...

y = 0, 1, 6, 35, 204, 1189, 6930, 40391, 235416, 1372105, 7997214, 46611179 ...

Match the x and y values for the triangle number == square number. For example, check that 466111792 = 65918161×65918162/2.



Bob Backstrom
~ Newsletter Editor ~

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