Non-committing encryption achieved only semantic security

in contrast

applications often require security against chosen ciphertext attacks.A main ingredient in the previous adaptive universally composable (UC)oblivious transfer protocols are non-committing encryptions.the previous proposals are not UC secure against adaptive adversaries in the so-called non-erase model.A new UC secure oblivious transfer protocols were proposed and schemes utilize two primitives of the verifiably smooth projective hashing and deniable encryption as constructed by.the double trapdoor decryption mechanism based on trapdoor commitment.Our construction is based on the decisional composite residuosity in common reference string (CRS) model.We constructed a two-message (1-round) string oblivious transfer protocol

which improves computationa

l efficient that supports message spaces of size exponential and save

O(n)

-1 rounds communications efficient than bit-OT protocols.