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Luhn algorithm

The Luhn algorithm or Luhn formula (creator: IBM scientist Hans Peter Luhn), also known as the "modulus 10" or "mod 10" algorithm, is a simple check digit formula used to validate a variety of identification numbers. The purpose is to design a numbering scheme in such a way that when a human is entering a number, a computer can quickly check it for errors. The algorithm is in the public domain and is in wide use today. It is specified in ISO/IEC 7812-1. It is not intended to be a cryptographically secure hash function; it was designed to protect against accidental errors, not malicious attacks. Most credit card numbers and many government identification numbers use the algorithm as a simple method of distinguishing valid numbers from mistyped or otherwise incorrect numbers.

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Article summary

The Luhn algorithm or Luhn formula (creator: IBM scientist Hans Peter Luhn), also known as the "modulus 10" or "mod 10" algorithm, is a simple check digit formula used to validate a variety of identification numbers. The purpose is to design a numbering scheme in such a way that when a human is entering a number, a computer can quickly check it for errors. The algorithm is in the public domain and is in wide use today. It is specified in ISO/IEC 7812-1. It is not intended to be a cryptographically secure hash function; it was designed to protect against accidental errors, not malicious attacks. Most credit card numbers and many government identification numbers use the algorithm as a simple method of distinguishing valid numbers from mistyped or otherwise incorrect numbers.

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  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

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