SLIDE 57 ❙✉♣♣♦rt✐♥❣ ❙❧✐❞❡s ❊♥❝r②♣t❡❞ ❈r❡❞❡♥t✐❛❧ ❙❝❤❡♠❡
■ss✉❛♥❝❡ ❢♦r (I, U)
U ❛♥❞ I ❦♥♦✇ ❤, ③, ❝✶, ❝✷, ③✶, ③✷, ❛✵, ❜✵, ˜ ❢ , (❡✐✵)✷
✐=✶ α ∈❘ Z∗
q,
β, γ ∈❘ Zq ❤′ ← ❤α, ③′ ← ③α ❛′ ← ❤β
✵ ❣γ❛,
❜′ ← (③′)β(❤′)γ❜α δ✐ ∈❘ Zq, ❝′
✐ ← ❝✐ · (❣, ❢ )δ✐
③′
✐ ← ③✐ · (❤✵, ˆ
❢ )δ✐ ❡′
✐ ← (③′ ✐ )β(❝′ ✐ )γ❡✐ · (❛, ˜
❢ )δ✐
✷ ✐=✶
❝′ ← H([❝′
✐ , ③′ ✐ , ❡′ ✐ ]✷ ✐=✶; ❤′, ③′, ❛′, ❜′)
❝ ← ❝′ + β ♠♦❞ q
❝
− − − − − − − − − − → r ← ❝①✵ + ✇ ♠♦❞ q
r
← − − − − − − − − − − ❛ ? = ❣r❤−❝
✵
, ❜ ? = ❤r③−❝ ˜ ❢
?
= ❢ r ˆ ❢ −❝, (❡✐
?
= ❝r
✐ ③−❝ ✐
)✷
✐=✶
r′ ← r + γ ♠♦❞ q
✷✾ ✴ ✷✶