Add RSA4096 to the PIV algorithm set

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- `RSA4096` alongside the existing algorithms: `perso generate-key`,
+  `perso import-key`, CSR/self-signed-cert signing, and profile key
+  mechanisms.
+- `perso generate-key --create-key-object` - the same dev/eval fallback
+  `import-key` already had.
+
 ## [1.0.3] - 2026-08-31
 
 ### Changed

docs/factory/pre-personalization-profiles.rst

@@ -110,7 +110,7 @@ Profile YAML
        attributes: [IMPORTABLE]
 
 **Mechanisms**: ``AES128``, ``AES192``, ``AES256``, ``RSA2048``, ``RSA3072``,
-``ECCP256``, ``ECCP384``, ``CS2``, ``CS7``.
+``RSA4096``, ``ECCP256``, ``ECCP384``, ``CS2``, ``CS7``.
 
 **Access modes** (used for ``contact``/``contactless`` on both containers and
 keys): ``ALWAYS``, ``NEVER``, ``PIN``, ``VCI`` (contact-interface-only, no

docs/piv/piv-personalization.rst

@@ -109,8 +109,8 @@ mechanism the slot has no object for returns ``6A80``.
 ECC P-256 everywhere, accepts explicit RSA only for ``--profile ms-logon`` on
 9A (the one built-in shape with an RSA object, and the one Windows needs —
 the ECC default warns there), and elsewhere refuses RSA early rather than
-failing on the card. RSA-1024 and
-RSA-4096 are removed from the build; the CLI never offers them.
+failing on the card. RSA-1024 is removed from the build; the CLI never offers
+it.
 
 .. _piv-personalization-import-key:
 

src/cryptnox_id_cli/applets/piv/constants.py

@@ -52,12 +52,9 @@
     0x2E: "PIV-SM-CS7 (AES-256/SHA-384)",
 }
 
-# Algorithms this OpenFIPS201 FIPS build actually implements. RSA-4096 (0x16) is
-# included: on-card createKey + GENERATE for RSA-4096 is confirmed on the D600/SCP03
-# hardware (returns a real 512-byte modulus), gated only by the chip's DF2B max-RSA
-# = 0x1000 on a non-fused card. NOTE: this covers on-card key GENERATION and key
-# objects; the host-side key-IMPORT/sign helpers (keyimport.py) still cover only
-# RSA-2048/3072, so external RSA-4096 import is a separate, not-yet-implemented path.
+# Algorithms this OpenFIPS201 FIPS build actually implements. A chip whose DF2B
+# configuration caps RSA below a requested size answers 6F00; the CLI maps that to
+# a size-cap message on GENERATE/import.
 SUPPORTED_ALGORITHMS: frozenset[int] = frozenset(
     {0x07, 0x05, 0x16, 0x08, 0x0A, 0x0C, 0x11, 0x14, 0x27, 0x2E}
 )

src/cryptnox_id_cli/applets/piv/keyimport.py

@@ -51,7 +51,7 @@
 # Mechanism -> (curve, scalar/point sizes) for ECC, modulus size for RSA.
 _EC_BY_MECH: dict[int, type[ec.EllipticCurve]] = {0x11: ec.SECP256R1, 0x14: ec.SECP384R1}
 _EC_SCALAR_LEN = {0x11: 32, 0x14: 48}
-_RSA_MODULUS_LEN = {0x07: 256, 0x05: 384}
+_RSA_MODULUS_LEN = {0x07: 256, 0x05: 384, 0x16: 512}
 
 # Host-side slot policy (SP 800-78 per-key-reference algorithm table): PKI slots
 # and the retired key history accept the four asymmetric mechanisms; 9B is
@@ -133,11 +133,11 @@ def mechanism_for_key(key) -> int:
             if key.key_size == k * 8:
                 return mech
         raise KeyImportError(
-            f"RSA-{key.key_size} not supported; this applet takes RSA-2048 or RSA-3072."
+            f"RSA-{key.key_size} not supported; this applet takes RSA-2048, RSA-3072 or RSA-4096."
         )
     raise KeyImportError(
         f"unsupported key type {type(key).__name__}; this applet takes "
-        "ECC P-256/P-384 and RSA-2048/3072."
+        "ECC P-256/P-384 and RSA-2048/3072/4096."
     )
 
 

src/cryptnox_id_cli/applets/piv/perso.py

@@ -36,7 +36,7 @@
 _EC_CURVES = {0x11: ec.SECP256R1, 0x14: ec.SECP384R1}
 
 # Asymmetric algorithm name -> mechanism id (those this applet supports).
-ALGORITHMS = {"ECCP256": 0x11, "ECCP384": 0x14, "RSA2048": 0x07, "RSA3072": 0x05}
+ALGORITHMS = {"ECCP256": 0x11, "ECCP384": 0x14, "RSA2048": 0x07, "RSA3072": 0x05, "RSA4096": 0x16}
 
 
 def pad_pin(value: bytes, length: int = 8) -> bytes:

src/cryptnox_id_cli/applets/piv/profiles.py

@@ -24,6 +24,7 @@
     "AES256": 0x0C,
     "RSA2048": 0x07,
     "RSA3072": 0x05,
+    "RSA4096": 0x16,
     "ECCP256": 0x11,
     "ECCP384": 0x14,
     "CS2": 0x27,

src/cryptnox_id_cli/cli/commands/piv.py

@@ -805,7 +805,10 @@ def perso() -> None:
 @perso.command("generate-key")
 @click.option("--slot", required=True, help="Key slot hex, e.g. 9A.")
 @click.option(
-    "--algorithm", default="ECCP256", show_default=True, help="ECCP256/ECCP384/RSA2048/RSA3072."
+    "--algorithm",
+    default="ECCP256",
+    show_default=True,
+    help="ECCP256/ECCP384/RSA2048/RSA3072/RSA4096.",
 )
 @click.option(
     "--default-keys",
@@ -816,9 +819,21 @@ def perso() -> None:
 @click.option(
     "--out", "out_", type=click.Path(dir_okay=False), help="Write public-key PEM to FILE."
 )
+@click.option(
+    "--create-key-object",
+    is_flag=True,
+    help="If the slot has no key object for this (slot, algorithm) pair, create one "
+    "first (PUT DATA ADMIN, non-finalized cards only) - same dev/eval fallback as "
+    "`import-key --create-key-object`.",
+)
 @click.pass_obj
 def perso_generate_key(
-    app: AppContext, slot: str, algorithm: str, default_keys: bool, out_: str | None
+    app: AppContext,
+    slot: str,
+    algorithm: str,
+    default_keys: bool,
+    out_: str | None,
+    create_key_object: bool,
 ) -> None:
     """Generate a key pair ON-CARD; the private key never leaves the card.
 
@@ -850,7 +865,13 @@ def perso_generate_key(
                 f"Replace the certified key in slot {slot}?", default=False
             ):
                 raise click.Abort()
-        public_key = _generate_key_on_card(PivAdmin(session), keys, ref, mech, label=slot)
+        adm = PivAdmin(session)
+        if create_key_object:
+            _select(session)
+            probe = session.transmit(keyimport.probe_apdu(ref, mech), context=f"probe {slot}")
+            if probe.sw == 0x6A86:
+                _create_key_object(app, adm, keys, ref, mech, False, slot)
+        public_key = _generate_key_on_card(adm, keys, ref, mech, label=slot)
     pem = perso_mod.public_key_pem(public_key)
     der = public_key.public_bytes(
         serialization.Encoding.DER, serialization.PublicFormat.SubjectPublicKeyInfo
@@ -890,6 +911,8 @@ def _generate_key_on_card(adm: PivAdmin, keys, ref: int, mech: int, *, label: st
     adm.select()
     adm.open(keys)
     resp = adm.send(perso_mod.generate_keypair_apdu(ref, mech), context=f"GENERATE {label}")
+    if resp.sw == 0x6F00 and keyimport.rsa_modulus_len(mech):
+        raise CryptnoxError(f"GENERATE key {label} failed (SW=6F00): {_IMPORT_SW_HINTS[0x6F00]}.")
     if not resp.ok:
         raise StatusWordError(resp.sw1, resp.sw2, context=f"GENERATE key {label}")
     return perso_mod.parse_public_key(mech, resp.data)
@@ -994,6 +1017,10 @@ def signer(digest: bytes) -> bytes:
         "CRT attribute does not match; try the other --rsa-form"
     ),
     0x6700: "element too long for the transport (chaining should have engaged - report this)",
+    0x6F00: (
+        "the chip refuses this key size - its pre-issuance maximum-RSA configuration "
+        "(DF2B) caps RSA below it, and that is factory-set before the card is secured"
+    ),
 }
 
 
@@ -2130,7 +2157,7 @@ def _collect_quickstart_facts(session, ref: int, mech: int) -> tuple[CardFacts,
     "--algorithm",
     default="ECCP256",
     show_default=True,
-    help="ECCP256, ECCP384, RSA2048 or RSA3072; the slot must have a key object for it "
+    help="ECCP256, ECCP384, RSA2048, RSA3072 or RSA4096; the slot must have a key object for it "
     "(RSA: only ms-logon's 9A among the built-in profiles — pass RSA2048 explicitly "
     "for Windows, which does not enumerate EC keys).",
 )

src/cryptnox_id_cli/crypto/csr.py

@@ -22,6 +22,7 @@
     0x14: (hashlib.sha384, "sha384_ecdsa", 48),
     0x07: (hashlib.sha256, "sha256_rsa", None),
     0x05: (hashlib.sha256, "sha256_rsa", None),
+    0x16: (hashlib.sha256, "sha256_rsa", None),
 }
 
 _RDN = {