# Precondition

## SNS ID

Yabumi uses unique numbers to identify various SNS sites. For example, Discord is ID 1, X is ID 2, etc.. To reduce gas costs, this numbering scheme has been adopted.

## Signatures

The following three components are used for backend signature generation:

1. User ID on the SNS platform (e.g., 123456789).
2. SNS ID (e.g., 1).
3. Minted wallet address (e.g., 0x123456789... - a 40-digit hexadecimal value).

## JointedID

The User ID on the SNS platform and the SNS ID are combined using an underscore, resulting in a JointedID. For example, 123456789\_1.

## Hashing

User ID, JointedID and minted wallet address are concatenated and hashed. This hashed value is used as the signature message.