signal-desktop/protos/UnidentifiedDelivery.proto

package signalservice;

option java_package = "org.whispersystems.libsignal.protocol";
option java_outer_classname = "WhisperProtos";

message ServerCertificate {
    message Certificate {
        optional uint32 id  = 1;
        optional bytes  key = 2;
    }

    optional bytes certificate = 1;
    optional bytes signature   = 2;
}

message SenderCertificate {
    message Certificate {
        optional string            sender       = 1;
        optional string            senderUuid   = 6;
        optional uint32            senderDevice = 2;
        optional fixed64           expires      = 3;
        optional bytes             identityKey  = 4;
        optional ServerCertificate signer       = 5;
    }

    optional bytes certificate = 1;
    optional bytes signature   = 2;
}

message UnidentifiedSenderMessage {

    message Message {
        enum Type {
            PREKEY_MESSAGE = 1;
            MESSAGE        = 2;
        }

        optional Type              type              = 1;
        optional SenderCertificate senderCertificate = 2;
        optional bytes             content           = 3;
    }

    optional bytes ephemeralPublic  = 1;
    optional bytes encryptedStatic  = 2;
    optional bytes encryptedMessage = 3;
}