Adaptively secure broadcast encryption with small system parameters

mzhandry.stanford.edu We build the first public-key broadcast encryption system that simultaneously achieves adaptive security against arbitrary number of colluders, has small system parameters, and has a security proof based on non-interactive falsifiable assumptions. Our scheme is built from composite order multilinear maps and enjoys a ciphertext overhead, private key size, and public key size that are are all poly-logarithmic in the total number of users. Previous broadcast schemes with similar parameters are either proven secure in a weaker static model, or rely on powerful tools such as program obfuscation and involve non-falsifiable assumptions.