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ISBN-10

ISBN-10 checksum using modulo 11 with weighted positions and possible X check digit Standard book identifier validation used worldwide in publishing.

Properties

Property	Value
Category	Checksums
Sub-category	Publication Identifier
Security status	🎓 Educational Only
Complexity	Intermediate
Inventor	International Organization for Standardization (ISO)
Year	1970
Origin	Not specified
Source	algorithms/checksum/isbn.js

Security

Status: 🎓 Educational Only

Known vulnerabilities

Issue	Description	Mitigation
Not Cryptographically Secure	Designed for accidental error detection only, not security	—
Limited Error Detection	Cannot detect all types of transcription errors	—

Notes

• Format: 10 digits (9 data + 1 check)
• Weights: 1,2,3,4,5,6,7,8,9 applied left to right (equivalently 10,9,…,2 read right to left)
• Algorithm: check digit d10 chosen so that sum(i=1..10, i * digit_i) ≡ 0 (mod 11)
• Check digit: 0 if remainder is 0, ‘X’ (=10) if remainder is 1, otherwise 11 minus the remainder
• Example: 0-306-40615-9 (Structured Computer Organization, Tanenbaum)
• Superseded by ISBN-13 in 2007
• Detects: all single-digit errors and most transposition errors

Documentation

• ISO 2108 Standard
• ISBN User’s Manual
• Library of Congress ISBN
• ISBN on Wikipedia

References

• International ISBN Agency
• Publisher Guidelines
• WorldCat Library Database

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — Valid ISBN-10: 0-306-40615-9

Field	Value
input	00030006040006010509
expected	01

Vector 2 — Invalid ISBN-10: 0-306-40615-3

Field	Value
input	00030006040006010503
expected	00

Vector 3 — Valid ISBN-10: 0-19-605688-3

Field	Value
input	00010906000506080803
expected	01

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