Decrypt

Galera peguei um "Store" em inglês.. mais ele encrypta o numero do cartão de crédito do cliente e não consigo cobrar..preciso saber como decryptar no caso.. eis o codigo onde ele usa a função:

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	SQL = "INSERT INTO Orders (CustomerID,SessionID,OrderDate,ShipFirstName,ShipLastName,ShipAddress1,ShipAddress2,ShipCity,ShipState,ShipProvince,ShipZIP,ShipCountry,ShipPhone,ShipFax,ShipEmail,Gift,GiftMessage,PriorityShipping,PromotionCode,SubTotal,Tax,Shipping,Total,CardTypeID,CardNumber,ThreeDigitCode,ExpDate,CardHolderName"

	If Discount > 0 Then SQL = SQL & ",Discount"

	SQL = SQL & ") VALUES ("

	SQL = SQL & CustomerID & ", "

	SQL = SQL & "'" & SID & "', "

	SQL = SQL & "'" & Date() & "', "

	SQL = SQL & "'" & FixStr(ShipFirstName) & "', "

	SQL = SQL & "'" & FixStr(ShipLastName) & "', "

	SQL = SQL & "'" & FixStr(ShipAddress1) & "', "

	SQL = SQL & "'" & FixStr(ShipAddress2) & "', "

	SQL = SQL & "'" & FixStr(ShipCity) & "', "

	SQL = SQL & "'" & FixStr(ShipStateID) & "', "

	SQL = SQL & "'" & FixStr(ShipProvince) & "', "

	SQL = SQL & "'" & FixStr(ShipZIP) & "', "

	SQL = SQL & "'" & FixStr(ShipCountry) & "', "

	SQL = SQL & "'" & FixStr(ShipPhone) & "', "

	SQL = SQL & "'" & FixStr(ShipFax) & "', "

	SQL = SQL & "'" & FixStr(ShipEmail) & "', "

	SQL = SQL & Gift & ", "

	SQL = SQL & "'" & FixStr(GiftMessage) & "', "

	SQL = SQL & PriorityShipping & ", "

	SQL = SQL & "'" & FixStr(PromotionCode) & "', "

	SQL = SQL & SubTotal & ", "

	SQL = SQL & Tax & ", "

	SQL = SQL & Shipping & ", "

	SQL = SQL & Total & ", "

	SQL = SQL & CardTypeID & ", "

	SQL = SQL & "'" & Replace(Space(Len(CreditCardNumber) - 4), " ", "X") & Right(CreditCardNumber, 4) & "', "

	SQL = SQL & "'" & FixStr(ThreeDigitCode) & "', "

	SQL = SQL & "'" & ExpirationDate & "', "

	SQL = SQL & "'" & FixStr(CardHolderName) & "' "

	If Discount > 0 Then SQL = SQL & ", " & Discount

	SQL = SQL & ")"

	'Response.End

	Conn.Execute(SQL)

Estão vendo esse Replace.. dai aparece tudo XXXXX só mostra os 4 ultimos caracteres!

Alguém pode me Ajudar ?

Obrigado!