keymanager.proto

syntax = "proto3";
package spire.plugin.server.keymanager.v1;
option go_package = "github.com/spiffe/spire-plugin-sdk/proto/spire/plugin/server/keymanager/v1;keymanagerv1";

service KeyManager {
    // Generates a new private key with the given ID. If a key already exists
    // under that ID, it is overwritten and given a different fingerprint. See
    // the PublicKey message for more details on the role of the fingerprint.
    rpc GenerateKey(GenerateKeyRequest) returns (GenerateKeyResponse);

    // Gets the public key information for the private key managed by the
    // plugin with the given ID. If a key with the given ID does not exist,
    // NOT_FOUND is returned.
    rpc GetPublicKey(GetPublicKeyRequest) returns (GetPublicKeyResponse);

    // Gets all public key information for the private keys managed by the
    // plugin.
    rpc GetPublicKeys(GetPublicKeysRequest) returns (GetPublicKeysResponse);

    // Signs data with the private key identified by the given ID. If a key
    // with the given ID does not exist, NOT_FOUND is returned. The response
    // contains the signed data and the fingerprint of the key used to sign the
    // data. See the PublicKey message for more details on the role of the
    // fingerprint.
    rpc SignData(SignDataRequest) returns (SignDataResponse);
}

message PublicKey {
    // Required. The ID of the key, as provided when the key was created.
    string id = 1;

    // Required. The type of the key.
    KeyType type = 2;

    // Required. The public key data (PKIX encoded).
    bytes pkix_data = 3;

    // Required. Fingerprint of the public key. The (id,fingerprint) tuple
    // uniquely identifies an "instance" of the key. When a key is overwritten
    // the fingerprint changes, indicating a different "instance" of that key
    // under the given ID.
    //
    // Proper key rotation requires that SPIRE not overwrite a key while it is
    // actively being used to sign data so that if the rotation operation
    // fails, SPIRE still has a valid key to use. SPIRE compares the
    // fingerprint returned from signing operations with the fingerprint it
    // expected for the key as a way to detect when it has mismanaged keys.
    // This is a mitigating measure and not expected to fail under normal
    // circumstances.
    //
    // There is no requirement that plugins persist the fingerprint. It can be
    // newly generated as long as it remains consistent for a given "instance"
    // of the key during runtime.
    //
    // The fingerprinting algorithm is also left to plugin implementations. A
    // native implementation is a non-cryptographic hash over the PKIX data.
    string fingerprint = 4;
}

message GenerateKeyRequest {
    // Required. The ID to give the generated key (or to identify the existing
    // key to overwrite (see GenerateKey).
    string key_id = 1;

    // Required. The type of the key to generate.
    KeyType key_type = 2;
}

message GenerateKeyResponse {
    // Required. The generated key.
    PublicKey public_key = 1;
}

message GetPublicKeyRequest {
    // Required. The ID of the key to retrieve.
    string key_id = 1;
}

message GetPublicKeyResponse {
    // Required. The public key to return.
    PublicKey public_key = 1;
}

message GetPublicKeysRequest {
}

message GetPublicKeysResponse {
    // Required. The public keys managed by the KeyManager. May be empty.
    repeated PublicKey public_keys = 1;
}

message SignDataRequest {
    message PSSOptions {
        // Required. The salt length.
        int32 salt_length = 1;

        // Required. The hash algorithm.
        HashAlgorithm hash_algorithm = 2;
    }

    // Required. The ID of the key to use to sign the data.
    string key_id = 1;

    // Required. The data to sign.
    bytes data = 2;

    // Required. The signature options. The PSS options are only valid
    // for RSA keys.
    oneof signer_opts {
        HashAlgorithm hash_algorithm = 3;
        PSSOptions pss_options = 4;
    }
}

message SignDataResponse {
    // Required. The signature of the data.
    bytes signature = 1;

    // Required. The fingerprint of the key used to sign the data.
    string key_fingerprint = 2;
}

enum KeyType {
    UNSPECIFIED_KEY_TYPE = 0;
    EC_P256 = 1;
    EC_P384 = 2;
    RSA_2048 = 3;
    RSA_4096 = 4;
}

enum HashAlgorithm {
    UNSPECIFIED_HASH_ALGORITHM = 0;
    // These entries (and their values) line up with a subset of the go
    // crypto.Hash constants.
    SHA224 = 4;
    SHA256 = 5;
    SHA384 = 6;
    SHA512 = 7;
    SHA3_224 = 10;
    SHA3_256 = 11;
    SHA3_384 = 12;
    SHA3_512 = 13;
    SHA512_224 = 14;
    SHA512_256 = 15;
}