A method of executing an algorithm includes protecting an electronic device by affine masking. The electronic device executes operations on secret variables x, the secret variables x being binary vectors of a given size N other than zero. The method further includes replacing the secret variables x using an affine masking operation, by the following affine function: m(x)=R.x+r, where R is a random invertible binary matrix with N rows and N columns and r is a random binary vector of size N.