▁commits ▁to . ▁ ▁A ▁real - life ▁application ▁of ▁this ▁problem ▁exists , ▁when ▁people ▁( o ften ▁in ▁media ) ▁commit ▁to ▁a ▁decision ▁or ▁give ▁an ▁answer ▁in ▁a ▁" se aled ▁en velope ", ▁which ▁is ▁then ▁opened ▁later . ▁" Let ' s ▁find ▁out ▁if ▁that ' s ▁what ▁the ▁candidate ▁answered ", ▁for ▁example ▁on ▁a ▁game ▁show , ▁can ▁serve ▁as ▁a ▁model ▁of ▁this ▁system . ▁ ▁Zero - know ledge ▁proofs ▁ ▁One ▁particular ▁motiv ating ▁example ▁is ▁the ▁use ▁of ▁commit ment ▁schemes ▁in ▁zero - know ledge ▁proofs . ▁Comm it ments ▁are ▁used ▁in ▁zero - know ledge ▁proofs ▁for ▁two ▁main ▁purposes : ▁first , ▁to ▁allow ▁the ▁pro ver ▁to ▁particip ate ▁in ▁" cut ▁and ▁choose " ▁proofs ▁where ▁the ▁ver ifier ▁will ▁be ▁presented ▁with ▁a ▁choice ▁of ▁what ▁to ▁learn , ▁and ▁the ▁pro ver ▁will ▁reve al ▁only ▁what ▁corresponds ▁to ▁the ▁ver ifier ' s ▁choice . ▁Comm it ment ▁schemes ▁allow ▁the ▁pro ver ▁to ▁specify ▁all ▁the ▁information ▁in ▁advance , ▁and ▁only ▁reve al ▁what ▁should ▁be ▁revealed ▁later ▁in ▁the ▁proof . ▁Comm it ments ▁are ▁also ▁used ▁in ▁zero - know ledge ▁proofs ▁by ▁the ▁ver ifier , ▁who ▁will ▁often ▁specify ▁their ▁choices ▁ahead ▁of ▁time ▁in ▁a ▁commit ment . ▁This ▁allows ▁zero - know ledge ▁proofs ▁to ▁be ▁composed ▁in ▁parallel ▁without ▁reve aling ▁additional ▁information ▁to ▁the ▁pro ver . ▁ ▁Sign ature ▁schemes