X-APPLE-I-MD-M.
The value of x-apple-i-md-m is not just encoded data; it is cryptographically signed with a device-specific key stored in the . Apple’s backend validates the signature. Any modification to the string—even a single bit—will cause the signature check to fail, and Apple’s server will return an HTTP 403 Forbidden or 401 Unauthorized . x-apple-i-md-m
: Contains machine information or a Machine ID . x-apple-i-md-m