add JwtService

src/main/kotlin/ltd/hlaeja/service/JwtService.kt

@@ -0,0 +1,25 @@
+package ltd.hlaeja.service
+
+import io.jsonwebtoken.Jwts
+import java.security.interfaces.RSAPrivateKey
+import java.util.UUID
+import ltd.hlaeja.property.JwtProperty
+import ltd.hlaeja.util.PrivateKeyProvider
+import org.springframework.stereotype.Service
+
+@Service
+class JwtService(
+    jwtProperty: JwtProperty,
+) {
+
+    private var privateKey: RSAPrivateKey = PrivateKeyProvider.load(jwtProperty.privateKey)
+
+    suspend fun makeIdentity(device: UUID): String {
+        return Jwts.builder()
+            .claims()
+            .add("device", device)
+            .and()
+            .signWith(privateKey)
+            .compact()
+    }
+}