# MOAI

Fully homomorphic encryption lets a cloud evaluate a Transformer directly on ciphertext, but rotations and format conversions have kept it slow. MOAI chains column packing and diagonal packing into one fixed flow across all layers and evaluates Softmax and LayerNorm without rotations, needing only 9,648 homomorphic rotations across all matrix multiplications of BERT-base. On a single A100 GPU its end-to-end evaluation time is 52.8% lower than THOR, amortized to 2.36 minutes per input.

Fully homomorphic encryption lets a cloud evaluate a Transformer directly on ciphertext, but rotations and format conversions have kept it slow. MOAI chains column packing and diagonal packing into one fixed flow across all layers and evaluates Softmax and LayerNorm without rotations, needing only 9,648 homomorphic rotations across all matrix multiplications of BERT-base. On a single A100 GPU its end-to-end evaluation time is 52.8% lower than THOR, amortized to 2.36 minutes per input.