module CryptBufferConcern::Arithmetic

Public Instance Methods

add(n, mod: 256, offset: 0) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 20
def add(n, mod: 256, offset: 0)
  real_mod = [256,mod].min

  tmp = bytes.map do |b|
    val = (b + n) % real_mod
    val >= offset ? val : val+offset
  end
  CryptBuffer(tmp)
end
hdist(other,normalize: false) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 30
def hdist(other,normalize: false)
  if normalize
    hamming_distance(other) / length.to_f
  else
    hamming_distance(other)
  end
end
mod_sub(n,mod: 256) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 9
def mod_sub(n,mod: 256)
  tmp = bytes.map do |byte|
    val = byte.to_bn.mod_sub(n,mod).to_i
  end
  CryptBuffer(tmp)
end
modulus(mod) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 4
def modulus(mod)
  real_mod = sanitize_modulus(mod)
  CryptBuffer( bytes.map{|b| b % real_mod } )
end
sub(n) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 16
def sub(n)
  CryptBuffer( bytes.map{|byte| byte -n } )
end

Private Instance Methods

hamming_distance(other) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 40
def hamming_distance(other)
  (self ^ other).bits.join.count("1") 
end
sanitize_modulus(mod) click to toggle source
# File lib/crypto-toolbox/crypt_buffer/concerns/arithmetic.rb, line 44
def sanitize_modulus(mod)
  (mod > 0) ? mod : 256
end