IMSI & ICCID Parser + Log Masker

IMSI and ICCID, decoded

The IMSI (International Mobile Subscriber Identity, defined by ITU-T E.212) is the number that identifies a subscriber inside a mobile network. It is at most 15 digits and splits into three parts: the MCC (3-digit mobile country code, e.g. 226 for Romania), the MNC (2 or 3 digits identifying the operator), and the MSIN — the subscriber serial the home network assigns. Whether the MNC is two or three digits depends on the country, so this parser resolves the split using the MCC before reading the MSIN.

The ICCID (Integrated Circuit Card Identifier, defined by ITU-T E.118) is printed on the SIM card itself. It begins with the telecom major-industry identifier 89, followed by a country code, an issuer identifier and account digits, and ends with a single Luhn check digit — the same checksum that guards a bank card number. Romanian SIMs typically start 8940. The tool recomputes the Luhn digit so you can immediately see whether an ICCID was transcribed correctly.

Why mask logs in your browser

An IMSI, an ICCID and a phone number are personal data under the GDPR: they single out a specific subscriber. That is a problem the moment a diagnostic log, a ticket or a trace leaves the lab bench and lands in a shared tracker, an email or an attachment. The masker scans free text and detects identifiers by their structure — an IMEI by its Luhn check, an IMSI by a valid mobile country code, an ICCID by its 89 prefix, plus phone numbers and IPv4/IPv6 addresses. Because a missed identifier is a leak, it errs toward masking, replacing every distinct value with a stable alias such as IMSI_1. The same value always maps to the same alias, so the correlation you need for debugging survives while the raw identifier is gone.

Because the identifiers here are real subscriber data, this page deliberately loads no analytics and makes no network requests — you can confirm it in your browser's DevTools Network tab. Everything happens in memory and nothing is ever uploaded or stored.