Struct FileTpm 

pub struct FileTpm { /* private fields */ }

File-backed TPM. Stores private keys under <root>/<HEX>.privkey[-ed25519] files and reads them back on demand. All operations take &self; concurrent access is safe because each call performs an independent open/read/close.

Implementations

impl FileTpm

pub fn open(root: impl AsRef<Path>) -> Result<Self, FileTpmError>

Open or create a TPM at the given directory. Creates the directory tree (with 0o700 permissions) if absent.

pub fn open_default() -> Result<Self, FileTpmError>

Open the default TPM at $HOME/.ndn/ndnsec-key-file/, mirroring ndn-cxx BackEndFile’s default constructor.

pub fn locator(&self) -> String

Locator string the PIB persists for this TPM. Matches ndn-cxx’s canonical form: tpm-file: for the default location, or tpm-file:<absolute-path> for a custom one. ndn-cxx’s parseAndCheckTpmLocator rejects mismatches at KeyChain open time, so writing the wrong string here will break interop.

pub fn save_raw( &self, key_name: &Name, kind: TpmKeyKind, der: &[u8], ) -> Result<(), FileTpmError>

Save raw DER bytes for a key. The DER must already be in the algorithm’s canonical form for kind:

• Rsa → PKCS#1 RSAPrivateKey
• EcdsaP256 → SEC1 ECPrivateKey
• Ed25519 → PKCS#8 PrivateKeyInfo

The bytes are base64-encoded and written with 0o400.

pub fn load_raw( &self, key_name: &Name, ) -> Result<(TpmKeyKind, Vec<u8>), FileTpmError>

Load raw DER bytes for a key. Tries the .privkey file first (RSA / ECDSA), then .privkey-ed25519. Returns the kind alongside the bytes so callers can dispatch on algorithm.

pub fn delete(&self, key_name: &Name) -> Result<(), FileTpmError>

Delete a key file (whichever form exists).

pub fn has_key(&self, key_name: &Name) -> bool

Check whether a key exists in the TPM.

pub fn generate_ed25519( &self, key_name: &Name, ) -> Result<[u8; 32], FileTpmError>

Generate a fresh Ed25519 key, persist it under the sentinel suffix, and return the 32-byte raw seed. Callers that want a Signer should pass the seed to Ed25519Signer::from_seed.

pub fn sign( &self, key_name: &Name, region: &[u8], ) -> Result<Bytes, FileTpmError>

Sign region with the key stored under key_name. Returns raw signature bytes. Algorithm is determined by which file form exists on disk.

pub fn public_key(&self, key_name: &Name) -> Result<Vec<u8>, FileTpmError>

Derive the public key bytes for key_name. Format matches what the PIB’s key_bits column expects: SubjectPublicKeyInfo DER for RSA / ECDSA, raw 32-byte key for Ed25519.

pub fn export_to_safebag( &self, key_name: &Name, certificate: Bytes, password: &[u8], ) -> Result<SafeBag, SafeBagError>

Export key_name as a crate::safe_bag::SafeBag for transfer to another machine. Bundles the password-encrypted private key with the certificate the caller looked up from the PIB.

The on-disk private key is converted to an unencrypted PKCS#8 PrivateKeyInfo first (RSA goes PKCS#1 → PKCS#8, ECDSA goes SEC1 → PKCS#8, Ed25519 is already PKCS#8 on disk) and then encrypted via PBES2 + PBKDF2-HMAC-SHA256 + AES-256-CBC inside the rustcrypto pkcs8 crate’s encrypt method. The resulting EncryptedPrivateKeyInfo is wire-compatible with what ndnsec export and OpenSSL i2d_PKCS8PrivateKey_bio produce.

Caveat: Ed25519 SafeBags roundtrip ndn-rs ↔ ndn-rs but not to ndn-cxx, because ndn-cxx tpm-file has no Ed25519 path regardless of how the bytes arrive on disk (back-end-file.cpp:130-139 rejects Ed25519 at the algorithm switch). RSA and ECDSA-P256 SafeBags roundtrip with ndnsec in both directions.

pub fn import_from_safebag( &self, safebag: &SafeBag, key_name: &Name, password: &[u8], ) -> Result<Bytes, SafeBagError>

Import a crate::safe_bag::SafeBag as a stored private key under key_name. Decrypts the embedded EncryptedPrivateKeyInfo with password, dispatches on the PKCS#8 algorithm OID to pick the on-disk format, converts back to the FileTpm form (PKCS#1 / SEC1 / PKCS#8), and writes it.

Returns the certificate Data wire bytes from the SafeBag so the caller can insert them into their PIB. FileTpm itself does not store certs — the certificate side of the bag is the PIB’s responsibility.

key_name is an explicit argument because the SafeBag does not record where the key should land in any particular PIB — the caller is expected to extract it from the certificate’s Name (typically a prefix of the cert name) and pass it in.