SLUAAQ0 March   2025 BQ27Z558 , BQ27Z561 , BQ27Z561-R1 , BQ27Z561-R2 , BQ27Z746 , BQ27Z758 , BQ28Z610 , BQ28Z610-R1 , BQ34Z100-G1 , BQ34Z100-R2 , BQ4050 , BQ40Z50 , BQ40Z50-R1 , BQ40Z50-R2 , BQ40Z80 , BQ41Z50 , BQ41Z90

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Generating a Key File with BQKEYPACKAGER
    1. 1.1 SHA1 Process
      1. 1.1.1 How to Calculate SHA1 Key
    2. 1.2 SHA256 Process
    3. 1.3 ECC Process
  5. 2Programming a Key Into the Fuel Gauge With BQKEYPROGRAMMER
  6. 3Programming Keys in Production
  7. 4Summary
  8. 5References

1.3 ECC Process

The ECC keys come in a pair – the private key and the matching public key. Each key is 163-bit in length.

Both keys are required to be programmed into the gauge to run ECC authentication. The private key, which is the secret of the ECC authentication, is split into two (called KeyF and KeyC). Each ½ key can be programmed by a different entity (for example, by TI, pack makers, or system makers). This split keys programming option allows the OEM to be the only one knowing the actual value of the private key, while any programming entity only has partial knowledge of the private key.

Step 1: Download and install BQKEYPACKAGER.

Step 2: Open BQKEYPACKAGER and select the correct authentication scheme and corresponding device. For this example we selected ECC Key BQ40Z80.

Step 3: Input Authentication Key F + Key C, in this example the key is AAAA1111BBBB2222CCCC3333DDDD4444EEEE5555FF. Input the Public Key, in this example the key is FF66667777888899990000AAAA1111BBBB2222CCCC.

Step 4: Enter a password for the generated .bqk file and any comments to display in BQKEYPROGRAMMER. For these examples, the password is example1234567890 , and the comment is example.

Step 5: Select Create bqKey file and choose output destination and file name.

ECC Example With BQ40z80 Figure 1-6 ECC Example With BQ40z80