Share folder from macOS to VirtualBox

Follow these steps to share a folder from your host macOS to guest Kali Linux running inside VirtualBox.

Step 1: From your macOS, Go to "System Preferences... >> Sharing"

Step 2: Enable the File Sharing option and add a folder to share

Step 3: Open VirtualBox >> Select Kali Linux (or any other image)

Step 4: Click on "Settings >> Share Folder"

Step 5: Click on Add new shared folder button and add the same folder you previously added in macOS from Step 2

Step 6: Log in to your Kali Linux image

Step 7: Open Terminal and type the command "sudo adduser $USER vboxsf"

Step 8: Reboot Kali Linux

[Solved] error: ‘getrusage’ was not declared in this scope

Error:

vb_perf.cpp: In function ‘int main(int, const char**)’:

vb_perf.cpp:63:23: error: variable ‘main(int, const char**)::rusage rusage’ has initializer but incomplete type

   63 |         struct rusage rusage = { };

      |                       ^~~~~~

vb_perf.cpp:64:19: error: ‘RUSAGE_SELF’ was not declared in this scope

   64 |         getrusage(RUSAGE_SELF, &rusage);

      |                   ^~~~~~~~~~~

vb_perf.cpp:64:9: error: ‘getrusage’ was not declared in this scope; did you mean ‘rusage’?

   64 |         getrusage(RUSAGE_SELF, &rusage);

      |         ^~~~~~~~~

      |         rusage

Solution:

Include this header to your source code:

#include <sys/resource.h>

[How To] Use Cryptopp in Kali Linux

 Crypto++ is a popular C++ library for cryptography. Instruction in this article can be used to install Cryptopp for all operating systems similar to Kali Linux. Check out this article if you want to use it with Xcode in macOS.

Step 1: Download Crypto++ using this link

Step 2: Extract Crypto++ and switch to that directory from the terminal or shell.

Step 3: $ make

Step 4: $ make test

Step 5: $ sudo make install

Step 6: Compile your program using

g++ -I/usr/local/include -L/usr/local/lib yourCode.cpp -lcryptopp

Automate onboarding in Google Workspace

This tutorial demonstrates the use of Google Workspace apps to automate the onboarding experience for new users by adding them to a google group and sending automated welcome emails after they are added.

Step 1: Log in to Google Drive using your Google Workspace account and create a new Google Sheet.

Step 2: Go to Insert > Form and create a new Google Form.

Step 3: Add the email address and google group fields.

Step 4: Go to Tools > Script editor.

Step 5: In Apps Script > Go to Project Settings > Check the box for "Show "appsscript.json" manifest file in editor" option.

Step 6: Go to Editor > appsscript.json and change it to the following:

Automate User Creation in Google Workspace

This tutorial demonstrates how to automate the user creation process in Google workspace using Admin SDK.

Step 1: Log in to Google Drive using your Google Workspace account and create a new Google Sheet.

Step 2: Go to Insert > Form and create a new Google Form.

Step 3: Add the desired fields: First Name, Last Name, Recovery Email, Recovery Phone, Reporting Manager, Location, Title, Department, etc.

Step 4: Go to Tools > Script editor.

Step 5: In Apps Script > Go to Project Settings > Check the box for "Show "appsscript.json" manifest file in editor" option.

Step 6: Go to Editor > appsscript.json and change it to the following:

[How to] Redirect URL in WordPress

In this tutorial, I will walk you through redirecting a URL in WordPress without using any plugins.

You can open a Terminal or Command Prompt window and do the following:

$cd to /var/www/html
$ls -loa
$sudo nano .htaccess
Append to the end of file “Redirect 301 old-URL new-URL”
Save the file and exit

$sudo service apache2 restart

[How To] Generate KEY and IV for CryptoPP in C++

In this tutorial, I will share strategies to generate random keys and initialization vector in C++ using CryptoPP library.

Approach 1:

SecByteBlock key(32), iv(24);
AutoSeededRandomPool prng;
prng.GenerateBlock(key, key.size());
prng.GenerateBlock(iv, iv.size());

Approach 2:

SecByteBlock key(16), iv(16);

std::string password = "Super secret password";

DeriveKeyAndIV(password, "encryption example", 100, key, key.size(), iv, iv.size());

Oracle Virtualbox crashing (aborting) on macOS [Solved]

 I run into issues every time I update my VirtualBox version on my MacBook Pro. If you run into issues where you can't start a VM instance, try this fix.

Open Virtualbox >> Go to your VM image >> Click on Settings >> Go to Audio >> Uncheck the "Enable Audio" box.

Binary file (standard input) matches

Error code:

$ sudo cat /var/log/syslog | grep "tree"
Binary file (standard input) matches

Solution:

$ sudo cat /var/log/syslog | grep "tree" --text
Jul 14 17:43:00 osboxes kernel: [    3.042582] vboxguest: loading out-of-tree module taints kernel.
Jul 15 13:24:47 osboxes kernel: [    3.420002] vboxguest: loading out-of-tree module taints kernel.
Jul 15 13:54:22 osboxes kernel: [    3.027623] vboxguest: loading out-of-tree module taints kernel.
Sep 28 12:59:21 osboxes kernel: [    3.165531] vboxguest: loading out-of-tree module taints kernel.
Sep 28 13:46:04 osboxes kernel: [    2.755048] vboxguest: loading out-of-tree module taints kernel.
Sep 28 13:51:08 osboxes kernel: [    3.508174] vboxguest: loading out-of-tree module taints kernel.
Oct 19 21:04:41 osboxes kernel: [    2.762903] vboxguest: loading out-of-tree module taints kernel.
Oct 19 21:11:51 osboxes kernel: [    2.566860] vboxguest: loading out-of-tree module taints kernel.

[Solved] 'cryptopp/aes.h' file not found; Expected namespace name

If you are facing errors like "'cryptopp/aes.h' file not found" or getting "Expected namespace name" error for "using namespace CryptoPP;" or similar compilation errors, refer to the following settings:

• Add "/usr/local/include" in Header search paths
• Add "/usr/local/lib" in Library search paths
• Add -lcryptopp as a Linker flag

Refer to this article for more information: https://com.puter.tips/2021/02/how-to-use-cryptopp-in-xcode.html

[How To] Use Boost in Xcode

Using Boost C++ Libraries (https://www.boost.org/) is relatively easier than setting up Cryptopp. [Ref.: https://com.puter.tips/2021/02/how-to-use-cryptopp-in-xcode.html]

Step-1: Install boost libraries

$ brew install boost

Step-2: Link boost in Build Settings

• Navigate to Linking >> Other Linker Flags
• Add following flags as per your requirement
• -lboost_chrono
• -lboost_system
• -lboost_timer
• -lboost_regex

[Solved] code signature not valid for use in process using Library Validation

So I was working on a C++ project on Xcode, and I updated to the latest version of Xcode with recommended default settings; then I started having the following errors:

dyld: Library not loaded: /usr/local/lib/libcryptopp.dylib

  Referenced from: /Users/devharsh/Library/Developer/Xcode/DerivedData/server-bohvcuztzndrrzhcoglrvuijfasj/Build/Products/Debug/server

  Reason: no suitable image found.  Did find:

/usr/local/lib/libcryptopp.dylib: code signature in (/usr/local/lib/libcryptopp.dylib) not valid for use in process using Library Validation: mapped file has no cdhash, completely unsigned? Code has to be at least ad-hoc signed.

/usr/local/lib/libcryptopp.dylib: code signature in (/usr/local/lib/libcryptopp.dylib) not valid for use in process using Library Validation: mapped file has no cdhash, completely unsigned? Code has to be at least ad-hoc signed.

/usr/local/lib/libcryptopp.dylib: code signature in (/usr/local/lib/libcryptopp.dylib) not valid for use in process using Library Validation: mapped file has no cdhash, completely unsigned? Code has to be at least ad-hoc signed.

Program ended with exit code: 9

Solution:

• Go to Xcode > Targets > Build Settings
• Scroll down and go to the Signing tab
• Click on "Enable Hardened Runtime" and set it to "No"
• Recompile, and it should be fixed

[Solved] Google Sign-in Error: "sign in using your corporate mobile device"

The error when you try to sign in to any Google service like Youtube or Google Drive from a corporate account:

"We detected an unusual sign-in attempt. To ensure that someone else isn't trying to access your account, your organization needs you to sign in using your corporate mobile device (the phone or tablet you normally use to access your corporate account). If you don't have your corporate mobile device with you right now, try again later when you have your corporate mobile device with you. If you continue to have problems signing in, contact your administrator."

To suppress this warning, you can:

• Login to Google Admin: https://admin.google.com/

• Go to Users >> Open the user account

• Go to "Login challenge."

• Click on "Turn off for 10 mins."

• Try to log in again, and it should be fine

Unable to revert mtime: /Library/Fonts [Solved]

I was working on a python3 script on my macOS, and I came across this error:

% python3 my-random-script.py

Unable to revert mtime: /Library/Fonts

I got it solved by installing libmagic:

% brew install libmagic

NTRU in python3

NTRU:

• NTRU – Nth Degree Truncated Polynomial Ring Units (or R = Z[X] / ( X^N-1 ))
• NTRU is the first public-key cryptosystem not based on factorization or discrete logarithmic problems.
• NTRU is a lattice-based alternative to RSA and ECC and is based on the shortest vector problem in a lattice.
• NTRU is an open-source public-key cryptosystem that uses lattice-based cryptography to encrypt and decrypt data.
• It consists of two algorithms: NTRUEncrypt, which is used for encryption, and NTRUSign, which is used for digital signatures.
• Unlike other popular public-key cryptosystems, it is resistant to attacks using Shor's algorithm.
• NTRUEncrypt was patented, but it was placed in the public domain in 2017. NTRUSign is patented, but it can be used by software under the GPL.

Example in Python3:

% python3 --version

Python 3.9.1

% pip3 install --user sympy

% pip3 install --user numpy

% pip3 install --user docopt

[How To] Save Space on Google Photos

Google Photos is a photo-sharing and storage service developed by Google. It was announced in May 2015 and separated from Google+, the company's former social network. In its free tier, Google Photos stores unlimited photos and videos up to 16 megapixels and 1080p resolution, respectively (anything larger gets down-scaled to these sizes). This free tier will end on June 1, 2021. Photos and videos uploaded after that date get counted towards the 15 GB free quota shared across the user's Google services. There are subscriptions offered for users wanting to store their photos and videos at their "original" quality and requiring more storage than the 15 GB offered free.

Storage (GB)	Per Month (USD)	Annual (USD)
15	0	0
100	1.99	19.99
200	2.99	29.99
2000	9.99	99.99

You can check out how much storage you are using across Google services out of your quota of free 15 GB. Go to Google Drive and check the storage bar on the left side. Or you can click on the Setting button in Google Drive located on the Top Menu and click on the Storage option and check how much storage you are using. You can click on "View items taking up storage" and see which files occupy more space. If Google Photos is taking up space, then do the following to save some space.

[How To] Install Free SSL Certificate for WordPress

In this tutorial, I have installed a free SSL certificate from Let's Encrypt using the Certbot tool on Google Cloud Platform VM running Debian OS that hosts a WordPress site using Apache server. You can follow similar steps for other Cloud providers / OS distributions / CMS vendors / Web servers.

Part-1: Configure Virtual Host for your domain on Apache

cd /var/www/html

wp option update home 'https://example.com'

wp option update siteurl 'https://example.com'

sudo nano /etc/apache2/sites-available/example.com.conf

sudo apache2ctl configtest

sudo a2ensite example.com

sudo systemctl reload apache2

Random Number Generation in C++

Code:

//

//  main.cpp

//  VaultBox

//

//  Created by Devharsh Trivedi on 3/11/21.

//

#include <iostream>

#include <iomanip>

#include <string>

#include <map>

#include <random>

#include <cmath>

#include <vector>

int main(int argc, const char * argv[]) {

    std::random_device ranDev;

    unsigned int num_ranDev = ranDev();

    std::cout << num_ranDev << std::endl;

    std::mt19937 mtGen(num_ranDev);

    std::vector<unsigned long> indexes(10);

    

    iota(indexes.begin(), indexes.end(), 0);

    for(int i=0; i<10; i++) {

        std::cout << indexes[i] << "\t";

    }

    std::cout << std::endl;

[How To] Save as an unlocked PDF

Steps to save a locked (password protected) PDF as an unlocked PDF:

1. Download / Save / Copy the locked PDF to a folder
2. Open Google Chrome
3. Go to File Menu >> Open File >> Select your locked PDF
4. Enter password
5. Click on the Print button and select Save as a PDF
6. The saved PDF will be unlocked

setsockopt: Protocol not available [Solved]

Problem code:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Solution:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Ref.: https://stackoverflow.com/a/59807281/4064166

[How To] Fix "Waiting to Upload" in iCloud Drive

1. Check if you have enough free storage on iCloud

2. Go to Settings (iOS / iPadOS) or System Preferences (macOS) >> iCloud >> Sign Out

3. Wait for a minute or two after you have successfully logged out

4. Log in to iCloud again

5. Go to iCloud settings and >> iCloud Drive >> Options... >> select the checkbox for "Desktop & Documents Folder" >> Done

Best tablets to buy in 2021

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Brand - Apple

Storage - 256 GB

Display - 10.9"

Resolution - 2360 x 1640

Operating System - iPadOS 14

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iPad Air glass screen protector - https://amzn.to/3aG5xY1

[How To] Use Cryptopp in Xcode

Crypto++ Library is a free C++ class library of cryptographic schemes. Currently the library contains the following algorithms:

                   algorithm type  name

 authenticated encryption schemes  GCM, CCM, EAX, ChaCha20Poly1305 and
                                   XChaCha20Poly1305

        high speed stream ciphers  ChaCha (8/12/20), ChaCha (IETF), Panama, Salsa20,
                                   Sosemanuk, XSalsa20, XChaCha20

           AES and AES candidates  AES (Rijndael), RC6, MARS, Twofish, Serpent,
                                   CAST-256

                                   ARIA, Blowfish, Camellia, CHAM, HIGHT, IDEA,
                                   Kalyna (128/256/512), LEA, SEED, RC5, SHACAL-2,
              other block ciphers  SIMON (64/128), Skipjack, SPECK (64/128),
                                   Simeck, SM4, Threefish (256/512/1024),
                                   Triple-DES (DES-EDE2 and DES-EDE3), TEA, XTEA

  block cipher modes of operation  ECB, CBC, CBC ciphertext stealing (CTS),
                                   CFB, OFB, counter mode (CTR), XTS

     message authentication codes  BLAKE2s, BLAKE2b, CMAC, CBC-MAC, DMAC, GMAC, HMAC,
                                   Poly1305, Poly1305 (IETF), SipHash, Two-Track-MAC,
                                   VMAC

                                   BLAKE2s, BLAKE2b, Keccack (F1600), SHA-1,
                   hash functions  SHA-2 (224/256/384/512), SHA-3 (224/256/384/512),
                                   SHAKE (128/256), SipHash, SM3, Tiger,
                                   RIPEMD (128/160/256/320), WHIRLPOOL

                                   RSA, DSA, Deterministic DSA, ElGamal,
          public-key cryptography  Nyberg-Rueppel (NR), Rabin-Williams (RW), LUC,
                                   LUCELG, EC-based German Digital Signature (ECGDSA),
                                   DLIES (variants of DHAES), ESIGN

   padding schemes for public-key  PKCS#1 v2.0, OAEP, PSS, PSSR, IEEE P1363
                          systems  EMSA2 and EMSA5

                                   Diffie-Hellman (DH), Unified Diffie-Hellman (DH2),
            key agreement schemes  Menezes-Qu-Vanstone (MQV), Hashed MQV (HMQV),
                                   Fully Hashed MQV (FHMQV), LUCDIF, XTR-DH

      elliptic curve cryptography  ECDSA, Deterministic ECDSA, ed25519, ECNR, ECIES,
                                   ECDH, ECMQV, x25519

          insecure or obsolescent  MD2, MD4, MD5, Panama Hash, DES, ARC4, SEAL
algorithms retained for backwards  3.0, WAKE-OFB, DESX (DES-XEX3), RC2,
     compatibility and historical  SAFER, 3-WAY, GOST, SHARK, CAST-128, Square
                            value

[How To] check if Intel SGX is enabled

Steps to check if Intel SGX is enabled on your system:

1. Download test-sgx.c from https://github.com/ayeks/SGX-hardware

2. % gcc test-sgx.c -o test-sgx

3. % ./test-sgx

eax: 806ea ebx: 4100800 ecx: 7ffafbbf edx: bfebfbff

stepping 10

model 14

family 6

processor type 0

extended model 8

extended family 0

smx: 0

Extended feature bits (EAX=07H, ECX=0H)

eax: 0 ebx: 29c67af ecx: 0 edx: 9c002600

sgx available: 1

sgx launch control: 0

CPUID Leaf 12H, Sub-Leaf 0 of Intel SGX Capabilities (EAX=12H,ECX=0)

eax: 0 ebx: 0 ecx: 0 edx: 0

sgx 1 supported: 0

sgx 2 supported: 0

MaxEnclaveSize_Not64: 0

MaxEnclaveSize_64: 0

CPUID Leaf 12H, Sub-Leaf 1 of Intel SGX Capabilities (EAX=12H,ECX=1)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 2 of Intel SGX Capabilities (EAX=12H,ECX=2)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 3 of Intel SGX Capabilities (EAX=12H,ECX=3)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 4 of Intel SGX Capabilities (EAX=12H,ECX=4)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 5 of Intel SGX Capabilities (EAX=12H,ECX=5)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 6 of Intel SGX Capabilities (EAX=12H,ECX=6)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 7 of Intel SGX Capabilities (EAX=12H,ECX=7)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 8 of Intel SGX Capabilities (EAX=12H,ECX=8)

eax: 0 ebx: 0 ecx: 0 edx: 0

CPUID Leaf 12H, Sub-Leaf 9 of Intel SGX Capabilities (EAX=12H,ECX=9)

eax: 0 ebx: 0 ecx: 0 edx: 0

4. sgx available = 1 means that the system has a CPU that supports Intel SGX

5. From sgx1 supported = 0 and max enclave size64 = 0 we infer that Intel SGX is disabled from BIOS

iOS v/s Android - Comparing 'Apples' to 'Oranges'

	Apple iOS	Google Android
Released	July 29, 2007	September 23, 2008
Latest Version	14	11
Website	https://www.apple.com/ios/ios-14/	https://www.android.com/
OS Model	Proprietary	Open Source
Languages	40	100
Assistant	Siri	Google Assistant
Apps	1,000,000 on App Store	2,000,000 on Play Store
Operating System	Unix	Linux
Latest Phone	iPhone 12	Pixel 5
Phone Website	https://www.apple.com/iphone	https://store.google.com/product/pixel_5

Let's compare some of the default apps on both platforms...