Convert String to Base64 and Base64 to String

The System.Text.Encoding class provides methods to convert string to Base64 and vice versa

String to Base64

The conversion involves two processes:

a. Convert string to a byte array

b. Use the Convert.ToBase64String() method to convert the byte array to a Base64 string

C#

byte[] byt = System.Text.Encoding.UTF8.GetBytes(strOriginal);
// convert the byte array to a Base64 string
strModified = Convert.ToBase64String(byt);

VB.NET

Dim byt As Byte() = System.Text.Encoding.UTF8.GetBytes(strOriginal)
' convert the byte array to a Base64 string
strModified = Convert.ToBase64String(byt)

Base64 string to Original String

In order to convert a Base64 string back to the original string, use FromBase64String(). The conversion involves two processes:

a. The FromBase64String() converts the string to a byte array

b. Use the relevant Encoding method to convert the byte array to a string, in our case UTF8.GetString();

C#

byte[] b = Convert.FromBase64String(strModified);
strOriginal = System.Text.Encoding.UTF8.GetString(b);

VB.NET

Dim b As Byte() = Convert.FromBase64String(strModified)
strOriginal = System.Text.Encoding.UTF8.GetString(b)

Check out some additional String functions over here 30 Common String Operations in C# and VB.NET