The user next computes SN = PRF(K, bsn) and sends SN to the Resource, along with a zero-knowledge proof that SN was computed correctly.
Potential Future Extensions
，这一点在91视频中也有详细论述
vfp=2, vsync=3, vbp=17: vertical front porch, sync pulse, and back porch (total frame = 240+2+3+17 = 262 lines)
User-friendly interface