FA-72560 / Check-digit algorithms / Member archive

ORCID complements the remainder against eleven · case 05

Every generated check character is off by one.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

ORCID identifier check (ISO 7064 MOD 11-2). Input is 16 characters, either plain or as four hyphen-separated groups of four (other hyphen layouts "malformed"); fifteen digits then a digit or uppercase X. Fold total = (total + digit) * 2 over the fifteen digits; the check value is (12 - total % 11) % 11 with 10 written X. Return [check character, whether it matches].

Why this case matters

Research information systems verify ORCID iDs before linking publications to authors.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression ["0000-9157-2825-059X"]	`["3", false]`	`["4", false]`	Failed

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