NCK code
generator.
Carrier unlock codes for your Alcatel LINKHUB HH71VM. Enter its 15-digit IMEI to calculate the NCK and all six other facility codes, in both full and short forms. Your IMEI stays in this tab.
Calculate unlock codes.
LOCAL CALCULATION. NOTHING UPLOADED.
No uploads, history, or remote lookup. Once this page has loaded, calculation works offline. Read the calculation source.
Network unlock code / NCK
Full code · 16 digits
Short code · 10 digits
The full code is the short code with the six-digit control value appended. Your firmware determines which form it expects. A wrong form can spend an unlock attempt.
All facility codes
Select a code to copy it. Only use the facility your device requests.
| Facility | Full · 16 digits | Short · 10 digits |
|---|
How the calculation works.
The calculation uses a single unkeyed SHA-1 hash over 32 bytes derived from the IMEI and two facility tags. It runs locally and does not require a dongle, account, vendor key, or online database.
1. Pack the IMEI
Prefix the 15 digits with zero, then pack two decimal digits per byte as BCD. This produces an eight-byte block.
2. Build the message
Repeat the block three times, separated by two four-byte tags. Their low byte selects the facility; the other tag bytes are zero.
3. Compute SHA-1
Hash the 32-byte message once, producing a 20-byte digest. The only inputs are the IMEI and facility tags.
4. Fold to decimal
Take the first 16 digest bytes. XOR each byte’s two nibbles and reduce modulo ten. The resulting digits form the full code.
The first ten digits are the short form; the last six are the control value. That split is a vendor display convention. The IMEI’s check digit is not validated by this algorithm.
View the synthetic example and self-test
Synthetic IMEI: 012345678901234
BCD: 00 12 34 56 78 90 12 34
NCK tags: C0 CD
SHA-1: 9f30457f2d72846f6cafb5f8d52aa2ed299974df
FACILITY SHORT CODE CONTROL FULL CODE
NCK 6318552905 478883 6318552905478883
NSCK 8532047882 407823 8532047882407823
SPCK 0942002456 328911 0942002456328911
SIM 1523150021 542477 1523150021542477
C 0536453544 527474 0536453544527474
Other 9308353322 504072 9308353322504072
T6 4862357454 041781 4862357454041781These are synthetic test values, not a suggested IMEI for your device.
Device support
and code formats.
The algorithm was recovered on the Alcatel LINKHUB HH71VM. One HH71VM has been unlocked on real hardware with a code from this calculation. Other models are unverified, even if they appear similar.
A device using a different scheme will reject the result and may spend an unlock attempt. Treat results for any model other than the HH71VM as unverified.
Seven facilities, two forms.
Facility tag pairs: NCK C0 CD, NSCK 52 C7, SPCK 80 44, SIM FD BE, C 43 7B, Other 6D 38, and T6 90 90. Only those two bytes change.
T6 exists in the vendor calculation but is not displayed by its interface; its purpose remains unidentified. Only enter a code for the facility explicitly requested by your device.
Common questions.
What is an NCK code?
NCK stands for Network Control Key. A network-locked modem asks for it to release its carrier lock and accept SIM cards from other operators.
Is my IMEI sent or saved anywhere?
The calculation runs in this browser. Your IMEI is not uploaded, logged, placed in a URL, or saved in browser storage. After this page loads, calculation works with the connection turned off.
Should I enter 10 digits or 16?
Some devices expect the short ten-digit form; others require all sixteen digits. There is no reliable universal way to tell in advance. Check what your firmware expects: entering the wrong form can consume an attempt even when the underlying calculation is correct.
What is the control value?
The final six digits of the full code. Vendor tools often print the short code followed by that value in parentheses. For firmware expecting sixteen digits, append it directly without spaces or parentheses.
Which of the seven codes should I use?
For a carrier network lock, use NCK. Other facilities correspond to network subset, service provider, corporate, or SIM personalisation and should only be used if explicitly requested. T6’s exact purpose is unidentified.
How many attempts are available?
The exact remaining count depends on the modem and its history. Failed attempts are limited, and exhausting the counter can permanently lock personalisation. Recheck both the IMEI and the required code length before using a result.
Can I use Python instead?
Yes. The offline Python tool performs the calculation locally without third-party dependencies.
Questions about this tool?
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