Encrypt and Decrypt in SQL Server

Its mandatory to create Master Key

Now we are creating an asymmetric key is a combination of public key and private key. A public key is used to encrypt the data and a private key to decrypt the data.

USE prasi
GO

CREATE MASTER KEY ENCRYPTION BY PASSWORD='Pr@S!C00l'

CREATE ASYMMETRIC KEY AsymKey   
WITH ALGORITHM = RSA_1024
go
DECLARE @EncryptedText VARBINARY(128)
DECLARE @Text VARCHAR(128)
DECLARE @DecryptedText VARCHAR(MAX)
SET @Text='I am Super Human'
SET @EncryptedText=ENCRYPTBYASYMKEY(ASYMKEY_ID(N'AsymKey'),@Text)
SET @DecryptedText=DECRYPTBYASYMKEY (ASYMKEY_ID(N'AsymKey'),@EncryptedText)
SELECT @Text AS 'TextToEncrypt',@EncryptedText AS 'EncryptedText',@DecryptedText AS 'DecryptedText'

we will create an symmetric key and encrypt and decrypt a string using this key.

DECLARE @PWD varchar(30) = 'Pr@S!C00l'

CREATE CERTIFICATE TESTCERT
ENCRYPTION BY PASSWORD = 'Pr@S!C00l'
WITH SUBJECT ='TEST CERTIFICATE',
START_DATE='12/10/2017', 
EXPIRY_DATE='11/01/2018'

DROP CERTIFICATE TESTCERT

CREATE SYMMETRIC KEY TestSymKey               
WITH ALGORITHM =AES_256
ENCRYPTION BY CERTIFICATE TestCert
GO

OPEN SYMMETRIC KEY TestSymKey
DECRYPTION BY CERTIFICATE TestCert 
WITH PASSWORD ='Pr@S!C00l'
GO


DECLARE @Text VARCHAR(MAX)
SET @Text = 'I am Super Human'

DECLARE @EncryptedText VARBINARY(128)
SET @EncryptedText = (SELECT ENCRYPTBYKEY(KEY_GUID(N'TestSymKey'),@Text))

DECLARE @DecryptedText VARCHAR(MAX)

SET @DecryptedText = (SELECT CONVERT(VARCHAR(MAX),DECRYPTBYKEY(@EncryptedText)))


SELECT @Text AS 'TextToEncrypt',@EncryptedText AS 'EncryptedText',@DecryptedText AS 'DecryptedText'

DROP SYMMETRIC KEY TestSymKey

GO 

CMD to hide partion hdd from explorer

Type below commands in cmd

diskpart
list disk
sel disk *
list volume
sel volume *
remove letter **
To Reassign type : assign letter **
* represents the number
** represents the Drive letter

To Encrypt files via Command prompt

Go to location and type below command

C:\Users\Desktop\New folder>CIPHER /E

cipher commands

    /D        Decrypts the specified files or directories.
    /E        Encrypts the specified files or directories. Directories will be
              marked so that files added afterward will be encrypted. The
              encrypted file could become decrypted when it is modified if the
              parent directory is not encrypted. It is recommended that you
              encrypt the file and the parent directory.

Advantages is :  other login users cant access and not accessible in other systems too.
    

Windows Command to know Wifi Password of already connected wifi device.

Type below commands in administrative mode in cmd:

   netsh wlan show profile

        will show already connected devices.

then

  netsh wlan show profile ***** key=clear

change ***** from 1st command value