MSSQL Convert a VARCHAR to Base64 encoding and vice-versa

Base64 to String (VARCHAR) and String (VARCHAR) to Base64.sql

-- VARCHAR TO Base64
IF OBJECT_ID (N'[dbo].[uFnStringToBase64]', N'FN') IS NOT NULL  
    DROP FUNCTION uFnStringToBase64;  
GO 
CREATE FUNCTION [dbo].[uFnStringToBase64]
(
    @InputString VARCHAR(MAX)
)
RETURNS VARCHAR(MAX)
AS
BEGIN
    RETURN (
		SELECT
			CAST(N'' AS XML).value(
                  'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
                , 'VARCHAR(MAX)'
            )
        FROM (
            SELECT CAST(@InputString AS VARBINARY(MAX)) AS bin
        ) AS RetVal
    )
END;
GO


-- Base64 To VARCHAR
IF OBJECT_ID (N'[dbo].[uFnBase64ToString]', N'FN') IS NOT NULL  
    DROP FUNCTION uFnBase64ToString;  
GO
CREATE FUNCTION [dbo].[uFnBase64ToString]
(
    @Input_Base64_Value VARCHAR(MAX)
)
RETURNS VARCHAR(MAX)
AS
BEGIN
    RETURN (
		SELECT
			CAST(
                CAST(N'' AS XML).value('xs:base64Binary(sql:variable("@Input_Base64_Value"))', 'VARBINARY(MAX)') 
            AS VARCHAR(MAX)
            ) AS RetVal
    )
END
GO

-- Usage
SELECT  [dbo].[uFnStringToBase64]('Encode Me') AS EncodedString
SELECT  [dbo].[uFnBase64ToString]([dbo].[uFnStringToBase64]('Encode Me')) AS DecodedString