Definition of Birthmark
Let p, q be programs and = be a given copy relation. Let f(p) be a set of characteristics extracted from p by a certain method f. Then f(p) is called birthmark of p under = iff both of the following conditions are satisfied.
Condition
- f(p) is obtained only from p itself (without any extra information)
- p = q -> f(p) = f(q)
Properties
Hopefully, the birthmark should satisfy these properties.
- Preservation Property
- Even if p is copied as p', birthmarks of p and p' should be the same.
- Distinction Property
- If p and q are independent, then birthmarks of p and q should be different.
