SYMMETRIC triple DES issue

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C#

cryptography

Hi team,

I've implement the symmetric key encryption /decryption in sql server using below Query

CREATE MASTER KEY ENCRYPTION
BY PASSWORD = 'Name@1'
GO

--Certificate
CREATE CERTIFICATE EncryptNameCert
WITH SUBJECT = 'NameCer@1'
GO

--Symmetric Key
CREATE SYMMETRIC KEY NameSymmetKey
WITH ALGORITHM = TRIPLE_DES ENCRYPTION
BY CERTIFICATE EncryptNameCert
GO

-- Alter varchar to varbinary : UserDetails

 ALTER TABLE UserDetails
   add TempName nvarchar(30);
 
  update UserDetails set TempName = Name;
  update UserDetails set Name = null;

  alter table UserDetails alter column Name decimal(1,0);
  alter table UserDetails alter column Name VARBINARY(256);
  

--Encrypt the data : Table - Update existing data : 
OPEN SYMMETRIC KEY NameSymmetKey DECRYPTION
BY CERTIFICATE EncryptNameCert
UPDATE UserDetails
SET 
 CardHolderName = null,
 
GO
UPDATE UserDetails
SET 
 CardHolderName = ENCRYPTBYKEY(KEY_GUID('NameSymmetKey'),TempName),
   
GO

in front-end user need to insert the details at the same need to read. so im trying to implement(string to varbinary /varbinary to string) the same flow through c# code but i couldn't achive the solution. i tried but i always got some issues relate to length related issue or issue occur here too

Convert.FromBase64String()

i have tried so many references 3DES (Triple-DES) in C#[(Triple-DES)]


[msdn]


[triple-des-encryption-and-decryption-using-user-provided-key]


please send me the sample code to fix to execute

What I have tried:

i tried the above link some others also , i need to implement symeetric key with triple DES .i changed the backend DB side. i need to convert the string to varbinary but i cant do the same symmetric conversion in c# with the same. i'm very tired to find the fix please help me out from this.