Concept - Copy Flag and Transfer Rules

Copy flag (*): allows grant (delegation), either with or without delegation of the copy flag itself (s.16).

Transfer $\{r,r^{\ast }\}$ on X from S to S’ is allowed if any of these hold (s.17):

1. $A[S,X]=r^{\ast }$ (S has right r on X, and the copy flag set)
2. $A[S,X]=\text{"owner"}$ (S owns X)
3. $A[S,X]=r$ and $A[S,S^{\prime }]=\text{"control"}$ (S has right r on X, and S created S’)

Delete $\{r\}$ on X from S’ is allowed if any of these hold (s.17): $A[S,X]=\text{"owner"}$, or $A[S,S^{\prime }]=\text{"control"}$ (slide prints the latter as S[S,S'], a typo).

Example using s.14: S1 has read* on F1, so S1 may transfer read on F1 to another subject.

Related: Concept - Access Matrix, Concept - Discretionary Access Control. Appears in 04 Access Control - Chunk 01 (s.1-28).