syntax = "proto2";
package hw.trezor.messages.thp;

// Sugar for easier handling in Java
option java_package = "com.satoshilabs.trezor.lib.protobuf";
option java_outer_classname = "TrezorMessageThp";

import "options.proto";

option (include_in_bitcoin_only) = true;

/**
 * Mapping between Trezor wire identifier (uint) and a Thp protobuf message
 */
enum ThpMessageType {
    reserved 0 to 999;  // Values reserved by other messages, see messages.proto

    ThpMessageType_ThpCreateNewSession = 1000 [(bitcoin_only)=true];
    ThpMessageType_ThpPairingRequest = 1006 [(bitcoin_only) = true];
    ThpMessageType_ThpPairingRequestApproved = 1007 [(bitcoin_only) = true];
    ThpMessageType_ThpSelectMethod = 1008 [(bitcoin_only) = true];
    ThpMessageType_ThpPairingPreparationsFinished = 1009 [(bitcoin_only) = true];
    ThpMessageType_ThpCredentialRequest = 1010 [(bitcoin_only) = true];
    ThpMessageType_ThpCredentialResponse = 1011 [(bitcoin_only) = true];
    ThpMessageType_ThpEndRequest = 1012 [(bitcoin_only) = true];
    ThpMessageType_ThpEndResponse = 1013 [(bitcoin_only) = true];
    ThpMessageType_ThpCodeEntryCommitment = 1016 [(bitcoin_only)=true];
    ThpMessageType_ThpCodeEntryChallenge = 1017 [(bitcoin_only)=true];
    ThpMessageType_ThpCodeEntryCpaceTrezor = 1018 [(bitcoin_only)=true];
    ThpMessageType_ThpCodeEntryCpaceHostTag = 1019 [(bitcoin_only)=true];
    ThpMessageType_ThpCodeEntrySecret = 1020 [(bitcoin_only)=true];
    ThpMessageType_ThpQrCodeTag = 1024 [(bitcoin_only)=true];
    ThpMessageType_ThpQrCodeSecret = 1025 [(bitcoin_only)=true];
    ThpMessageType_ThpNfcTagHost = 1032 [(bitcoin_only)=true];
    ThpMessageType_ThpNfcTagTrezor = 1033 [(bitcoin_only)=true];

    reserved 1100 to 2147483647;  // Values reserved by other messages, see messages.proto
}


/**
 * Numeric identifiers of pairing methods.
 * @embed
 */
enum ThpPairingMethod {
    SkipPairing = 1;          // Trust without MITM protection.
    CodeEntry = 2;            // User types code diplayed on Trezor into the host application.
    QrCode = 3;               // User scans code displayed on Trezor into host application.
    NFC = 4;                  // Trezor and host application exchange authentication secrets via NFC.
}

/**
 * @embed
 */
message ThpDeviceProperties {
    optional string internal_model = 1;               // Internal model name e.g. "T2B1".
    optional uint32 model_variant = 2;                // Encodes the device properties such as color.
    optional uint32 protocol_version_major = 3;       // The major version of the communication protocol used by the firmware.
    optional uint32 protocol_version_minor = 4;       // The minor version of the communication protocol used by the firmware.
    repeated ThpPairingMethod pairing_methods = 5;    // The pairing methods supported by the Trezor.
}

/**
 * @embed
 */
message ThpHandshakeCompletionReqNoisePayload {
    optional bytes host_pairing_credential = 1;       // Host's pairing credential
}

/**
 * Request: Ask device for a new session with given passphrase.
 * @start
 * @next Success
 */
message ThpCreateNewSession{
    optional string passphrase = 1;
    optional bool on_device = 2;       // User wants to enter passphrase on the device
    optional bool derive_cardano = 3;  // If True, Cardano keys will be derived. Ignored with BTC-only
}


/**
 * Request: Start pairing process.
 * @start
 * @next ThpPairingRequestApproved
 */
message ThpPairingRequest{
    optional string host_name = 1;     // Human-readable host name
}

/**
 * Response: Host is allowed to start pairing process.
 * @start
 * @next ThpSelectMethod
 */
message ThpPairingRequestApproved{
}

/**
 * Request: Start pairing using the method selected.
 * @start
 * @next ThpPairingPreparationsFinished
 * @next ThpCodeEntryCommitment
 */
message ThpSelectMethod {
    optional ThpPairingMethod selected_pairing_method = 1 [default=NFC];; 
}

/**
 * Response: Pairing is ready for user input / OOB communication.
 * @next ThpCodeEntryCpace
 * @next ThpQrCodeTag
 * @next ThpNfcTagHost
 */
message ThpPairingPreparationsFinished{
}

/**
 * Response: If Code Entry is an allowed pairing option, Trezor responds with a commitment.
 * @next ThpCodeEntryChallenge
 */
message ThpCodeEntryCommitment {
    optional bytes commitment = 1;     // SHA-256 of Trezor's random 32-byte secret
}

/**
 * Response: Host responds to Trezor's Code Entry commitment with a challenge.
 * @next ThpCodeEntryCpaceTrezor
 */
message ThpCodeEntryChallenge {
    optional bytes challenge = 1;      // Host's random 32-byte challenge
}



/**
 * Response: Trezor continues with the CPACE protocol.
 * @next ThpCodeEntryCpaceHostTag
 */
message ThpCodeEntryCpaceTrezor {
    optional bytes cpace_trezor_public_key = 1;  // Trezor's ephemeral CPace public key
}

/**
 * Request: User selected Code Entry option in Host. Host starts CPACE protocol with Trezor.
 * @next ThpCodeEntrySecret
 */
 message ThpCodeEntryCpaceHostTag {
    optional bytes cpace_host_public_key = 1;    // Host's ephemeral CPace public key
    optional bytes tag = 2;                      // SHA-256 of shared secret

}

/**
 * Response: Trezor finishes the CPACE protocol.
 * @next ThpCredentialRequest
 * @next ThpEndRequest
 */
message ThpCodeEntrySecret {
    optional bytes secret = 1;    // Trezor's secret
}

/**
 * Request: User selected QR Code pairing option. Host sends a QR Tag.
 * @next ThpQrCodeSecret
 */
message ThpQrCodeTag {
    optional bytes tag = 1;       // SHA-256 of shared secret
}

/**
 * Response: Trezor sends the QR secret.
 * @next ThpCredentialRequest
 * @next ThpEndRequest
 */
message ThpQrCodeSecret {
    optional bytes secret = 1;    // Trezor's secret
}

/**
 * Request: User selected Unidirectional NFC pairing option. Host sends an Unidirectional NFC Tag.
 * @next ThpNfcTagTrezor
 */
message ThpNfcTagHost {
    optional bytes tag = 1;       // Host's tag
}

/**
 * Response: Trezor sends the Unidirectioal NFC secret.
 * @next ThpCredentialRequest
 * @next ThpEndRequest
 */
message ThpNfcTagTrezor {
    optional bytes tag = 1;       // Trezor's tag
}

/**
 * Request: Host requests issuance of a new pairing credential.
 * @start
 * @next ThpCredentialResponse
 */
message ThpCredentialRequest {
    optional bytes host_static_pubkey = 1;       // Host's static public key used in the handshake.
    optional bool autoconnect = 2;               // Whether host wants to autoconnect without user confirmation
}

/**
 * Response: Trezor issues a new pairing credential.
 * @next ThpCredentialRequest
 * @next ThpEndRequest
 */
message ThpCredentialResponse {
    optional bytes trezor_static_pubkey = 1;     // Trezor's static public key used in the handshake.
    optional bytes credential = 2;               // The pairing credential issued by the Trezor to the host.
}

/**
 * Request: Host requests transition to the encrypted traffic phase.
 * @start
 * @next ThpEndResponse
 */
message ThpEndRequest {}

/**
 * Response: Trezor approves transition to the encrypted traffic phase
 * @end
 */
message ThpEndResponse {}

/**
 * Only for internal use.
 * @embed
 */
 message ThpCredentialMetadata {
    option (internal_only) = true;
    optional string host_name = 1;     // Human-readable host name
    optional bool autoconnect = 2;     // Whether host is allowed to autoconnect without user confirmation
}

/**
 * Only for internal use.
 * @embed
 */
 message ThpPairingCredential {
    option (internal_only) = true;
    optional ThpCredentialMetadata cred_metadata = 1; // Credential metadata
    optional bytes mac = 2;                           // Message authentication code generated by the Trezor
}

/**
 * Only for internal use.
 * @embed
 */
 message ThpAuthenticatedCredentialData {
    option (internal_only) = true;
    optional bytes host_static_pubkey = 1;            // Host's static public key used in the handshake
    optional ThpCredentialMetadata cred_metadata = 2; // Credential metadata
}