Convert String to Base64 and Base64 to String

System.Text.Encoding class provides methods to convert String to Base64 and vice-versa.

Convert String to Base64

First convert the string to a byte array and then 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)

Convert Base64 string to String

In order to convert a Base64 string back to the original string, use FromBase64String(). First FromBase64String() converts the string to a byte array and then 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)