Python3

`

def encryption(s):
        # Write your code here
        s_list = list(s)
        dim = math.sqrt(len(s_list))
        # matrix dimensions
        rows = math.floor(dim)
        cols = math.ceil(dim)
        # exception
        if (len(s_list) - (rows * cols)) > 0:
                rows = math.ceil(dim)
                cols = math.ceil(dim)
        # organize values in matrix
        matrix = [[None] * cols for _ in range(rows)]
        s_iter = iter(s_list)
        for row in range(rows):
                for col in range(cols):
                        matrix[row][col] = next(s_iter, "")
        # extract values from matrix: answer
        ans = []
        for col in range(cols):
                for row in range(rows):
                        ans.append(matrix[row][col])
                        if row == rows-1:
                                ans.append(" ")
                        else:
                                continue
        return "".join(ans)