Encrypt voting package

[FieldmanJR1]

As a Product Manager I want voting package to be encrypted so information about it is not available before the voting ends
AC1: User can create an encryption key
AC2: User can encrypt the Voting package with the key from AC1
AC3: Voting package from AC2 contains amount of votes for each candidate
AC4: User can resubmit the voting untill the end of the voting period
AC5: User is able to submit encryption key from AC1 to the contract