The provable security of one-time signature based broadcast authentication protocols was investigated.In the UC framework

a one-time signature based broadcast authentication model was proposed.Firstly

the one-time signature ideal functionality FOTS and the broadcast authentication ideal functionality FBAUTH were formally defined in the model.Then

one-time signature protocol HORS+ was proposed.At the same time

a broadcast authentication scheme πBAUTH was designed in the（FOTS

FREG）-hybrid model.Finally

based on the scheme πBAUTH

a new broadcast authentication protocol was then obtained by the combined use of HORS+.The result shows that HORS+ securely realizes the ideal func-tionality FOTS

and πBAUTH also realizes the ideal functionality FBAUTH.According to the composition theorem in the UC framework

the composed broadcast authentication protocol is UC secure and can be applied to broadcast the authenticated message in the resource-limited networks.