▁a ▁common ▁reference ▁frame , ▁so ▁that ▁they ▁can ▁guarantee ▁that ▁some ▁communication ▁events ▁are ▁spac eli ke ▁separated . ▁ ▁In ▁relativ istic ▁crypt ography , ▁it ▁is ▁assumed ▁that ▁each ▁party ▁particip ating ▁in ▁the ▁crypt ographic ▁task ▁has ▁various ▁trust ed ▁agents ▁that ▁collabor ate ▁to ▁implement ▁the ▁task . ▁The ▁agents ▁implement ▁the ▁protocol ▁by ▁performing ▁different ▁actions ▁at ▁various ▁points ▁in ▁spac etime . ▁The ▁agents ▁of ▁the ▁same ▁party ▁may ▁communicate ▁via ▁authentic ated ▁and ▁secure ▁channels , ▁which ▁can ▁be ▁implemented ▁with ▁previously ▁shared ▁secure ▁keys , ▁for ▁example ▁using ▁one - time ▁p ads . ▁▁ ▁Vari ous ▁tasks ▁investig ated ▁by ▁relativ istic ▁crypt ography ▁consist ▁in ▁tasks ▁of ▁m istr ust ful ▁crypt ography , ▁in ▁which ▁two ▁or ▁more ▁m istr ust ful ▁parties ▁must ▁collabor ate ▁to ▁implement ▁a ▁crypt ographic ▁task ▁while ▁at ▁the ▁same ▁time ▁being ▁guaranteed ▁that ▁other ▁parties ▁do ▁not ▁che at . ▁Ex amples ▁of ▁tasks ▁in ▁m istr ust ful ▁crypt ography ▁are ▁bit ▁commit ment , ▁coin ▁toss ing , ▁ob liv ious ▁transfer ▁and ▁secure ▁comput ations . ▁Key ▁distribution ▁does ▁not ▁belong ▁to ▁m istr ust ful ▁crypt ography , ▁because ▁in ▁this ▁case ▁the ▁parties ▁distrib uting ▁the ▁key ▁trust ▁each ▁other . ▁In ▁relativ istic ▁crypt ography , ▁each ▁particip ating ▁party ▁has ▁various ▁trust ed ▁agents , ▁who ▁collabor ate ▁with ▁each ▁other ▁by ▁performing ▁different ▁actions ▁at ▁various ▁spac etime ▁points . ▁For ▁example , ▁Alice ▁and ▁Bob