## Personalized Name

The Seeker can write a personalized name to the Provider during the first
pairing and when the user edits the name on the Seeker side. The Provider shall
allocate space to store the personalized name, supporting a maximum length of
48 bytes (UTF-8 encoded). To receive this name, the Provider's
[Additional Data characteristic](https://developers.google.com/nearby/fast-pair/specifications/characteristics#AdditionalData "Characteristic: Addiitonal Data") shall support writes of up to 64 bytes, as
the Seeker sends the name within an encrypted and authenticated packet requiring
16 bytes of overhead.

Writes to [Additional Data characteristic](https://developers.google.com/nearby/fast-pair/specifications/characteristics#AdditionalData "Characteristic: Addiitonal Data") with personalized
name may happen in 2 flows:

1. After initial pairing, the Seeker may write a personalized name to the Provider after writing the account key.
2. After a user modifies the personalized name on the Seeker, the Seeker will write the new name to the Provider:
   1. handshake from step 1 to step 4 in the [procedure](https://developers.google.com/nearby/fast-pair/specifications/service/gatt#procedure "GATT Procedure") to identify each other and know which account key will be used for the encryption and decryption of the name. In [Table 1.2.2](https://developers.google.com/nearby/fast-pair/specifications/characteristics#table1.2.2 "Table 1.2.2"):
      1. Set Message type to 0x10
      2. Set Flag Bit 1 to 1 to indicate it will be followed by Data characteristic.
      3. Set Data ID of [Table 1.2.2](https://developers.google.com/nearby/fast-pair/specifications/characteristics#table1.2.2 "Table 1.2.2") to 0x01 as personalized name.
   2. write the name to Data characteristic `FE2C1237-8366-4814-8EB0-01DE32100BEA`.

The Provider should notify to [Additional Data characteristic](https://developers.google.com/nearby/fast-pair/specifications/characteristics#AdditionalData "Characteristic: Addiitonal Data")
with personalized name when it is requested using Bit 2 in
[Table 1.2.1](https://developers.google.com/nearby/fast-pair/specifications/characteristics#table1.2.1 "Table 1.2.1").