A system is provided for inside-to-outside or outside-to-inside cryptographic coding that facilitates product authentication along a distribution channel. An association of authenticated, secured codes is generated between inner items (e.g., pharmaceutical doses such as pills, capsules, tablets) and outer items (e.g., packaging containing inner items). For instance, an inner code associated with a first item is used to generate (at least partially) an outer code associated with a second item that contains one or more first items. This process may be repeated multiple times with codes for outer items being a function of codes for inner items. The sequence of items may be authenticated by the dependent relationship between their codes.