Specs

append_check_digit(binary(), pos_integer()) :: binary()

Compute and append the check digit for a given number.

iex> Luhn.append_check_digit("7992739871")
"79927398713"

Specs

checksum(binary(), integer()) :: integer()

checksum(integer(), integer()) :: integer()

Calculate the checksum of a number.

This is known as the "mod 10" algorithm and the result will be zero if the check digit suffix is valid for the number.

iex> Luhn.checksum("79927398713")
0

Specs

compute_check_digit(input(), pos_integer()) :: check_digit()

Compute the check digit of a number.

iex> Luhn.compute_check_digit("7992739871")
3

iex> Luhn.compute_check_digit(7992739871)
3

Specs

valid?(number :: integer() | String.t(), base :: integer()) :: boolean()

Evaluates a given credit card number for its validity, with an optionally provided base.

# Accepts a string
iex(1)> Luhn.valid?("378282246310005")
true

# Or an integer
iex(2)> Luhn.valid?(378282246310005)
true

# Octal
iex(3)> Luhn.valid?("11111115", 8)
true

# Hexadecimal
iex(4)> Luhn.valid?("1580BB2EA887B", 16)
true