I'm having difficulties figuring out, what the 'full stop' means in the paper John Almeida - SHADOW NUMBERS PUBLIC KEY ENCRYPTION. Appreciated if someone can elaborate on it or have a list of similar notations explained.

$$B = (Sa . Sb) − 1$$

The 'full stop' inbetween Sa and Sb is what I'm trying to understand here specifically.

  • $\begingroup$ Just a warning: This paper smells strongly of crank, I would not expect the algorithm presented in it to be secure. $\endgroup$ Oct 29, 2017 at 15:22

1 Answer 1


Mathematical notation isn't strictly standardized and varies somewhat between papers. A dot (normally placed in the middle $\cdot$, but a typographically challenged author might substitute a period) usually denotes multiplication.

From the context of the paper it is clearly multiplication in this case:

After the two chosen values are multiplied, a product is derived and once the value of 1 is subtracted from the product, a first base value is obtained.

$$ B = (Sa . Sb) − 1$$

The base value:

B = (Sa . Sb) - 1 → (5 . 3) - 1 = 14

  • $\begingroup$ Also note that the authors failed to properly typeset exponentiation for RSA. $\endgroup$
    – SEJPM
    Oct 29, 2017 at 15:34

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