Bug 247471 – Audit use of cryptographically random functions

• Status: NEW
• Component: Platform

[Don Olmstead]

Cryptographically random numbers are expensive to generate and can have a negative performance impact. Determine if code using them should actually be using them instead of a weak random number.

[Darin Adler]

I just noticed that we have two identical functions in two different headers:

cryptographicallyRandomNumber
cryptographicallyRandomUint32

[Darin Adler]

Not necessarily part of this bug, but I suggest we do these 9 things:

1) Change the 3 callers of cryptographicallyRandomUint32 to use cryptographicallyRandomNumber instead.
2) Remove cryptographicallyRandomUint32.
3) Move cryptographicallyRandomUint64 to CryptographicallyRandomNumber.h
4) Move cryptographicallyRandomUnitInterval to CryptographicallyRandomNumber.h.
5) Rename cryptographicallyRandomUint64 to cryptographicallyRandomUInt64 or cryptographicallyRandom<uint64_t>.
6) Consider renaming cryptographicallyRandomNumber to cryptographicallyRandomUInt32 or cryptographicallyRandom<uint32_t>.
7) Consider renaming weakRandom to weakRandomUInt32 or weakRandom<uint32_t>.
8) Consider renaming RandomNumber.h to WeakRandomNumber.h.
9) Document that cryptographicallyRandomUnitInterval has only 32 bits of randomness in it to further discourage uninformed use of it.

[Radar WebKit Bug Importer]

<rdar://problem/102219729>