I noticed that several hash algorithms, in this case MD5, defines some constants.
MD5 defines 64 constant values (the shift count per round) which also gets expand (via sine) to a summand for a specific round. It is like a lookup table.
But I cannot see anything (no documentation, no implementation,...) that calls this table an substitution box (S-Box). But I saw some implementations that use a variable called "S" for this table. A hint?
So my question is: Is it valid to call this table an S-Box? Or is it only common to call this kind of table an S-Box when it's used into a real encryption/decryption?