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view libutil/iccid_luhn.c @ 64:dba24129027e
doc/ADM-PIN-numbering article written
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Tue, 23 Mar 2021 23:30:00 +0000 |
parents | 34bbb0585cab |
children |
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/* * This module implements a function for computing the Luhn check digit * for ICCIDs that follow the 18+1 convention. */ #include <sys/types.h> compute_iccid_luhn(digits) u_char *digits; { int i, dig, sum; sum = 0; for (i = 0; i < 18; i++) { dig = digits[i]; if (i & 1) { dig *= 2; if (dig > 9) dig -= 9; } sum += dig; } dig = sum % 10; if (dig) dig = 10 - dig; return dig; }