This is a User Defined Function to perform simple encryption on an input string. This is performed by transposing the ASCII value of each character in the string by the increment value (@increment in the parameter list)
Pass the function the string you wish encrypted and the increment value, which is normally 128 or 256
/*Encryption function*/
CREATE FUNCTION dbo.udfEncryptString (@input_str VARCHAR(100), @increment INT)
RETURNS NVARCHAR(100) WITH ENCRYPTION AS
BEGIN
DECLARE @encrypted_str NVARCHAR(100)
DECLARE @index INT
SET @index = 1
SET @encrypted_str = ''
/*
loop as long as @index is shorter than the
length of the input string
*/
WHILE @index <= LEN(@input_str)
BEGIN
--transpose the ASCII value of each character by @increment
SET @encrypted_str = @encrypted_str + NCHAR(ASCII(SUBSTRING(@input_str, @index, 1)) + @increment + @index - 1)
--incement the current index
SET @index = @index + 1
END
RETURN @encrypted_str
END
GO
/*Decryption function*/
CREATE FUNCTION dbo.udfDecryptString (@input_str NVARCHAR(100), @increment INT)
RETURNS VARCHAR(100) WITH ENCRYPTION AS
BEGIN
DECLARE @decrypted_str VARCHAR(100)
DECLARE @index INT
SET @index = 1
SET @decrypted_str = ''
WHILE @index <= LEN(@input_str)
BEGIN
SET @decrypted_str = @decrypted_str + CHAR(UNICODE(SUBSTRING(@input_str, @index, 1)) - @increment - @index + 1)
SET @index = @index + 1
END
RETURN @decrypted_str
END
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