संवत्सर २०७९_February_मार्च_2023

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March 12, 2022 in C and CPP

Understanding Identity Change for WhatsApp Business

Today a business may want to communicate private information with a customer via WhatsApp. In order to do that securely, the business must first establish trust that they are communicating with the right person via authentication (this is done off WhatsApp today).

Once trust is established between a business and a WhatsApp account, the business does not know when the person with access to the WhatsApp account may have changed.

Businesses using the WhatsApp Business API can choose to be notified when there was a potential update to a customer’s identity. This gives businesses a signal that the person behind the account may have changed.

In this situation, the best practice would be for the business to break trust and authenticate the user again to re-establish trust before continuing to send personal information.

If a business opts in to this feature, they will be informed when they receive messages from users who have potentially changed ownership and will be blocked from sending messages to such users until the business acknowledges it’s safe to send the message. This will protect the business and their customers from leaking sensitive information.

Trigger

The trigger for notifying a business is the identity for a WhatsApp account has changed.

When a business receives this signal they may want to invoke a re-authentication flow to ensure they are always exchanging personal information securely.

  1. The business opts in to receive notifications when WhatsApp identifies a WhatsApp account with whom they are communicating is potentially under control of a different person.
  2. When WhatsApp detects a potential change in the user’s cryptographic identity, WhatsApp sends notification to the business.
  3. The business breaks trust with user (for example, unlinking the WhatsApp as trusted channel on their CRM)
  4. The business initiates re-authentication workflow (typically done off WhatsApp).
  5. The business acknowledges receipt of notification and continues to communicate with the account when they deem it safe to do so (usually following successful authentication).

Note: All outgoing messages to the user will be blocked until the business acknowledges receipt of the notification signaling that the person in control of the WhatsApp account could have changed. Since it is the business’s responsibility to establish trust with the user before sharing sensitive information, the business is recommended to re-authenticate the user (off WhatsApp) before acknowledging the notification, which would enable the business and user to continue exchanging personal information on WhatsApp. Acknowledging the notification does not ensure the user is “trusted”.

January 9, 2022 in C and CPP, Php

http to https redirect htaccess wordpress

# BEGIN WordPress
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RewriteEngine On
RewriteCond %{HTTPS} !on           
RewriteRule ^(.*) https://%{SERVER_NAME}/$1 [R,L]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

HC-05 Bluetooth Module with TTL Output

December 3, 2021 in C and CPP

HC-05 Bluetooth Module with TTL Output

To setup Wireless Serial Communication, HC-05 Bluetooth Module is most demanding and popular due to its low price and extremely high features.

This module can be used in Master or Slave Mode and easy switchable between these two modes, By default Slave mode is configured.

Modes can be changed using AT Commands.

The slave mode in HC-05 cannot initiate a connection to another Bluetooth device, but can accept connections.Master mode can initiate a connection to other devices.


HC-05 Specifications:- 

Profiles: Bluetooth serial port Profile
Bluetooth protocol: Bluetooth Specification v2.0+EDR
Frequency: 2.4GHz ISM band
Modulation: GFSK(Gaussian Frequency Shift Keying)
Emission power: ≤4dBm, Class 2
Sensitivity: ≤-84dBm at 0.1% BER
Speed: Asynchronous: 2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps
Security: Authentication and encryptionPower supply: +3.3VDC 50mA
Working temperature: -20 ~ +75Centigrade
Dimension: 26.9mm x 13mm x 2.2 mm


HC-05 Applications:-

Embedded Projects
Industrial Applications
Computer and portable Devices
GPS receiver

Click

November 19, 2021 in C and CPP

This project uses AndroidX dependencies,

To enable jetifier, add those two lines to your gradle.properties file:

android.useAndroidX=true
android.enableJetifier=true

The Android Gradle plugin provides the following global flags that you can set in your gradle.properties file:

android.useAndroidX: When set to true, this flag indicates that you want to start using AndroidX from now on. If the flag is absent, Android Studio behaves as if the flag were set to false.

android.enableJetifier: When set to true, this flag indicates that you want to have tool support (from the Android Gradle plugin) to automatically convert existing third-party libraries as if they were written for AndroidX. If the flag is absent, Android Studio behaves as if the flag were set to false.

July 21, 2021 in C and CPP

When bucket size in the hash table is one

1.6 When bucket size in the hash table is one
A) Only collision occurs
B) Collisions and overflows occur simultaneously
C) Only overflow occurs
D) None of the above

July 21, 2021 in C and CPP

Order of magnitude of an algorithm refers to

1.5 Order of magnitude of an algorithm refers to
A) Frequency of execution
B) Computing time
C) Sum of frequencies of all its statements
D) None of the above