I do not agree. How will you reverse a salt with sufficient entropy? Imagine the salt is a 512 bit hex, the data is a ten decimal digit phone number, the generated hash is 512 bits of which the first 160 bits are used as the value. Now exactly how will you get the phone number back? Do you really think you can iterate over half of the possibilities of 512 bits in four hours?
If the "salt" is kept secret then I agree you can't brute force all the phone numbers so easily. But I don't agree that "salt" is the correct term for that technique.
