def eps_def(eps) :
    return ceil(abs(log(eps)))
mes_length = 256
eps = 1/1000000000
tag_length = eps_def(eps) + 1
epsilon = 1/(2^(eps_def(eps))epsilon = 1/(2^(eps_def(eps)))
key_length = ceil(3*tag_length +2*log(mes_length))
print('tag length:', tag_length)
print('epsilon:', epsilon)
print('key length:', key_length)