RSA Accumulator for Ruby 
Cryptographic accumulator based on the strong RSA assumption BBF18 in Ruby.
Installation
Add this line to your application's Gemfile:
gem 'rsa-accumulator'And then execute:
$ bundle
Or install it yourself as:
$ gem install rsa-accumulator
Usage
Setup accumulator
First, initialize the accumulator. Since the accumulator uses groups of unknown order, it can be generated in following ways:
require 'rsa-accumulator'
# using RSA modulus published by RSA Laboratory
acc = RSA::Accumulator.generate_rsa2048
# using Random RSA modulus with a specified bit length(default value is )
acc = RSA::Accumulator.generate_random(2048)
Adding elements and membership proof
You can add arbitrary String data to the accumulator.
acc.add('a', 'b')
proof = acc.add('c')
You can use inclusion proof to prove that an element exists in an accumulator.
acc.member?(proof)
Non membership proof
You can generate non-membership proof and prove that the elements does not exist in the accumulator.
members = %w(a b)
non_members = %w(c, d)
acc.add(*members)
proof = acc.prove_non_membership(members, non_members)
acc.non_member?(non_members, proof)
=> true
Delete element from accumulator
You can remove elements from the accumulator by providing the inclusion proof.
acc.add('a', 'b')
proof = acc.add('c')
acc.delete(proof)
acc.member?(proof)
=> false
Holding the product of all elements
This feature is experimental and has not been checked against large amounts of data.
acc = RSA::Accumulator.generate_rsa2048(hold_elements: true)
acc.add('a', 'b', 'c')
acc.add('d', 'e')
# acc has product of all elements in acc#products, so you can get membership proof.
proof = acc.prove_membership('b')