[Ongoing]-[300USDT]-NULS Sign Server development task

Bonus: 300 USDT equivalent of NULS
奖金:300 USDT等值NULS

The signing machine is an application that requires automatic transaction signing in a secure hosting environment,
Features:
Account creation, import, export
Transaction signature, signature verification
Signature of data
Data encryption and decryption
You can use the SDK provided
Note: You can refer to the signature machine design of other mainstream public chains

签名机是在安全托管环境中需要进行自动交易签名的应用程序,
功能:
账户的创建、导入、导出
交易的签名、签名验证
数据的签名
数据的加密、解密
可以使用已提供的SDK实现
注:可以参考其他主流公链的签名机设计