RozgarDesh (रोजगार देश)

Android Keystore In this post we will learn how to store a key in android provider keystore and encrypt and decrypt. Keystore KeyStore ks = KeyStore.getInstance("AndroidKeyStore"); SecretKey key = new SecretKeySpec(keyByte, alg); KeyStore.SecretKeyEntry secretKeyEntry = new KeyStore.SecretKeyEntry(key); // store key in keystore ks.setEntry( "keyName", new KeyStore.SecretKeyEntry(secretKeyEntry.getSecretKey()), new KeyProtection.Builder(KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT) .setBlockModes(KeyProperties.BLOCK_MODE_GCM) .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE) .build()); // get key from key store SecretKey keyStoreKey = (SecretKey) ks.getKey(" keyName", null); Encryption Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding"); cipher.init(Cipher.ENCRYPT_MODE, keyStoreKey); byte[] encryptedByte = c...

Python Input Output We use the print() function to output data to the standard output device (screen). Up till now, our programs were static. The value of variables were defined or hard coded into the source code. To allow flexibility we might want to take the input from the user. In Python, we have the input() function to allow this. The syntax for input() is s = input("Enter value: ") print (s )

Python Arithmetic Expression syntax is straightforward: the operators +, -, * and / work just like in most other languages print ( 2 + 2) print ( 50 - 5 * 6) print ( ( 50 - 5 * 6 ) / 4) print ( 8 / 5)

Python Control Flow if Statements The if statement is used for conditional execution x = 5 if x < 0 : print ( 'x is Negative' ) elif x == 0 : print ( 'x is Zero' ) elif x > 0 : print ( 'x is Positive' ) else : print ( 'x is not a number' ) The while statement The while statement is used for repeated execution as long as an expression is true x = 0 while x < 6 : print ( x ) x = x + 1 : for Statements In Python’s for statement iterates over the items of any sequence (a list or a string) fruits = ["apple", "orange", "banana", "cherry"] for fruit in fruits : print ( fruit ) The range() Function If you do need to iterate over a sequence of numbers, the built-in function range() comes in handy. It generates arithmetic progressions for i in range ( 5 ): print ( i ) Output 0 1 2 3 4 More example on range range ( 5 , 10 )...

Python Variables Variables are containers for storing data values. Unlike other programming languages, Python has no command for declaring a variable. A variable is created the moment you first assign a value to it. x = 5 y = "John" print (x) print (y) Variables do not need to be declared with any particular type and can even change type after they have been set. x = 5 # x is integer x = "John" # now x is a string Assign Value to Multiple Variables x, y = 5, 'John' print(x) print (y) You can also use the + character to add a variable to another variable x = "Python is" y = "awesome" print (x + y)

Python Comments In this post, We will learn about comments in Python. Comments can be used to explain Python code. Comments can be used to make the code more readable Single line comment # this is the first comment print ("Hello World") print ("Hello World") # this is the first comment Multi-line comment   # this is a comment # written in # more than on line "print ("Hello World") ''' this is a comment written in more than on line ''' "print ("Hello World")

Python Getting Started In this post, We will learn how to write first program in Python. Installation  Many system will have already Python installed. To check Python installed on Windows operating system run below command on windows command shell (cmd.exe). python --version To check Python installed on linux operating system run below command on Linux terminal. python --version Python Quick start Create a Python file hello_world.py here .py extension indicate that it is a python file. Let's write first Python program. Open hello_world.py in text editor and write below program in it. print ("Hello World") Run python file on command line. The way to run a python file is like this on the command line python hello_world.py Above program will print Hello World on your terminal.

Supplementary angles Supplementary angles  are two angles with a sum of  180 ^\circ 1 8 0 ∘ 180, degree . A common case is when they lie on the same side of a straight line.

Complementary Angle Complementary angles  are two angles with a sum of  90 ^\circ 9 0 ∘ 90, degree . A common case is when they form a right angle

Docker Installation Error docker info Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.39/info: dial unix /var/run/docker.sock: connect: permission denied sudo docker info Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? Fixes Install docker using below command sudo snap install docker