#include "mod_gpg/GpgStorage.h"
#include "cdc_hal/ISecureElement.h"
#include "cdc_core/Crypto.h"
#include "cdc_log.h"
#include <mbedtls/sha256.h>
#include <mbedtls/hkdf.h>
#include <mbedtls/md.h>
#include <mbedtls/platform_util.h>
#include <esp_random.h>
#include <string.h>

Classes
struct	cdc::mod_gpg::DecKeyStorage
struct	cdc::mod_gpg::AesKeyStorage

Namespaces
namespace	cdc
namespace	cdc::mod_gpg

Functions
static cdc::hal::ISecureElement *	get_se ()
static bool	pin_to_hash (const char pin, uint8_t hash_out)
	Computes SHA-256 over a PIN string.
static bool	derive_storage_key (uint16_t slot_id, const uint8_t pin_hash, uint8_t key_out)
	Derives a 32-byte storage key for a specific slot.
static void	build_aad (uint16_t slot_id, const uint8_t magic[MAGIC_SIZE], uint8_t aad_out[6])
	Builds the 6-byte AAD for a slot: slot_id (BE) \|\| magic (4).
static uint16_t	resolve_slot (uint16_t rel_index)
	Resolves an absolute R-Memory slot index relative to the module range.
void	gpg_storage_set_slot_range (uint16_t eccStart, uint16_t eccEnd)
void	gpg_storage_set_rmem_range (uint16_t rmemStart, uint16_t rmemEnd)
bool	gpg_storage_ready (void)
uint8_t	gpg_storage_sig_slot (void)
uint8_t	gpg_storage_dec_slot (void)
uint8_t	gpg_storage_aut_slot (void)
static bool	save_slot_encrypted (uint16_t slot_id, const uint8_t magic[MAGIC_SIZE], const uint8_t payload, size_t payload_len, uint8_t record_buf, size_t record_buf_len, const char *pin)
	Encrypts and writes an arbitrary payload to a slot.
static bool	load_slot_decrypted (uint16_t slot_id, const uint8_t magic[MAGIC_SIZE], uint8_t payload_out, size_t payload_len, const char pin)
	Reads and decrypts a payload from a slot.
bool	gpg_storage_save_dec_privkey (const uint8_t privkey, const char pin)
	Saves a DEC private key into R-Memory using PIN-bound AES-GCM.
bool	gpg_storage_load_dec_privkey (uint8_t privkey_out, const char pin)
	Loads and decrypts the DEC private key from R-Memory.
bool	gpg_storage_has_dec_privkey (void)
	Returns true if encrypted DEC private key record exists.
bool	gpg_storage_delete_dec_privkey (void)
	Deletes DEC private key record.
bool	gpg_storage_save_aes_key (const uint8_t key, size_t key_len, const char pin)
	Saves the symmetric AES key for PSO:DECIPHER (DO 0xD5).
bool	gpg_storage_load_aes_key (uint8_t key_out, size_t key_len_out, const char *pin)
	Loads the symmetric AES key from R-Memory.
bool	gpg_storage_has_aes_key (void)
	Returns true if a symmetric AES key record exists.
bool	gpg_storage_delete_aes_key (void)
	Deletes the symmetric AES key record.
void	gpg_storage_set_session_pin (const char *pin)
	Stores session PIN-derived key after successful PIN verification.
bool	gpg_storage_get_session_key (uint8_t *key_out)
	Returns current session key if session is active.
void	gpg_storage_clear_session (void)
	Clears the cached session key.

Variables
static const char *	TAG = "GPGStorage"
	Encrypted persistent storage for OpenPGP secret material.
static constexpr uint16_t	RMEM_SLOT_DEC_KEY = 1
	R-Memory slot offset for the DEC private key payload (= ECC slot 2).
static constexpr uint16_t	RMEM_SLOT_AES_KEY = 2
	R-Memory slot offset for the symmetric AES key payload (= ECC slot 3).
static constexpr uint8_t	DEC_KEY_MAGIC [4] = {'E', 'C', 'D', 'H'}
	Magic marker for encrypted DEC private key records.
static constexpr uint8_t	AES_KEY_MAGIC [4] = {'A', 'E', 'S', '1'}
	Magic marker for symmetric AES key records (DO 0xD5).
static constexpr size_t	MAGIC_SIZE = 4
static constexpr size_t	NONCE_SIZE = 12
static constexpr size_t	TAG_SIZE = 16
static constexpr size_t	PRIVKEY_SIZE = 32
static constexpr size_t	AES_MAX_KEY_SIZE = 32
static constexpr size_t	DEC_TOTAL_SIZE = MAGIC_SIZE + NONCE_SIZE + PRIVKEY_SIZE + TAG_SIZE
static constexpr size_t	AES_RECORD_PAYLOAD = 1 + AES_MAX_KEY_SIZE
static constexpr size_t	AES_TOTAL_SIZE = MAGIC_SIZE + NONCE_SIZE + AES_RECORD_PAYLOAD + TAG_SIZE
static constexpr char	HKDF_INFO [] = "GPG-STORAGE-V2"
	HKDF info string for storage key derivation.
static struct { ... }	s_storage

Function Documentation

◆ build_aad()

void build_aad	(	uint16_t	slot_id,
		const uint8_t	magic[MAGIC_SIZE],
		uint8_t	aad_out[6] )

static

Builds the 6-byte AAD for a slot: slot_id (BE) || magic (4).

Parameters

slot_id	Absolute R-Memory slot identifier.
magic	4-byte magic marker.
aad_out	6-byte output buffer.

Definition at line 171 of file GpgStorage.cpp.

References MAGIC_SIZE.

Referenced by load_slot_decrypted(), and save_slot_encrypted().

◆ derive_storage_key()

bool derive_storage_key	(	uint16_t	slot_id,
		const uint8_t *	pin_hash,
		uint8_t *	key_out )

static

Derives a 32-byte storage key for a specific slot.

Parameters

slot_id	Absolute R-Memory slot identifier (used in HKDF salt).
pin_hash	Optional 32-byte PIN hash; nullptr falls back to chip-bound key.
key_out	32-byte output buffer.

Returns: true on success.

Definition at line 129 of file GpgStorage.cpp.

References get_se(), and HKDF_INFO.

Referenced by load_slot_decrypted(), and save_slot_encrypted().

◆ get_se()

cdc::hal::ISecureElement * get_se ( )

static

Definition at line 105 of file GpgStorage.cpp.

References cdc::hal::getSecureElementInstance().

Referenced by derive_storage_key(), gpg_storage_delete_aes_key(), gpg_storage_delete_dec_privkey(), gpg_storage_has_aes_key(), gpg_storage_has_dec_privkey(), load_slot_decrypted(), and save_slot_encrypted().

◆ gpg_storage_aut_slot()

uint8_t gpg_storage_aut_slot ( void )

Definition at line 209 of file GpgStorage.cpp.

References s_storage.

Referenced by cmd_get_data(), cmd_internal_authenticate(), get_ecc_slot_for_key_ref(), gpg_generate_key(), openpgp_factory_reset(), and put_data_algo_attr().

◆ gpg_storage_clear_session()

void gpg_storage_clear_session ( void )

Clears the cached session key.

Definition at line 467 of file GpgStorage.cpp.

References s_storage.

Referenced by cmd_select(), gpg_storage_set_session_pin(), and openpgp_factory_reset().

◆ gpg_storage_dec_slot()

uint8_t gpg_storage_dec_slot ( void )

Definition at line 208 of file GpgStorage.cpp.

References s_storage.

Referenced by cmd_get_data(), get_ecc_slot_for_key_ref(), and gpg_generate_key().

◆ gpg_storage_delete_aes_key()

bool gpg_storage_delete_aes_key ( void )

Deletes the symmetric AES key record.

Definition at line 439 of file GpgStorage.cpp.

References get_se(), cdc::hal::OK, resolve_slot(), and RMEM_SLOT_AES_KEY.

◆ gpg_storage_delete_dec_privkey()

bool gpg_storage_delete_dec_privkey ( void )

Deletes DEC private key record.

Definition at line 378 of file GpgStorage.cpp.

References get_se(), cdc::hal::OK, resolve_slot(), and RMEM_SLOT_DEC_KEY.

Referenced by openpgp_factory_reset().

◆ gpg_storage_get_session_key()

bool gpg_storage_get_session_key ( uint8_t * key_out )

Returns current session key if session is active.

Parameters

key_out 32-byte output buffer.

Returns: true if session key is available.

Definition at line 459 of file GpgStorage.cpp.

References s_storage.

◆ gpg_storage_has_aes_key()

bool gpg_storage_has_aes_key ( void )

Returns true if a symmetric AES key record exists.

Definition at line 427 of file GpgStorage.cpp.

References AES_KEY_MAGIC, get_se(), MAGIC_SIZE, cdc::hal::OK, resolve_slot(), and RMEM_SLOT_AES_KEY.

Referenced by cmd_pso_decipher_aes().

◆ gpg_storage_has_dec_privkey()

bool gpg_storage_has_dec_privkey ( void )

Returns true if encrypted DEC private key record exists.

Definition at line 366 of file GpgStorage.cpp.

References DEC_KEY_MAGIC, DEC_TOTAL_SIZE, get_se(), MAGIC_SIZE, cdc::hal::OK, resolve_slot(), and RMEM_SLOT_DEC_KEY.

Referenced by cmd_pso_decipher(), and read_public_key().

◆ gpg_storage_load_aes_key()

bool gpg_storage_load_aes_key	(	uint8_t *	key_out,
		size_t *	key_len_out,
		const char *	pin )

Loads the symmetric AES key from R-Memory.

Parameters

key_out	Output buffer (must hold at least 32 bytes).
key_len_out	Receives the stored key length (16 or 32).
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 408 of file GpgStorage.cpp.

References AES_KEY_MAGIC, AES_RECORD_PAYLOAD, load_slot_decrypted(), resolve_slot(), and RMEM_SLOT_AES_KEY.

Referenced by cmd_pso_decipher_aes().

◆ gpg_storage_load_dec_privkey()

bool gpg_storage_load_dec_privkey	(	uint8_t *	privkey_out,
		const char *	pin )

Loads and decrypts the DEC private key from R-Memory.

Parameters

privkey_out	32-byte output buffer.
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 360 of file GpgStorage.cpp.

References DEC_KEY_MAGIC, load_slot_decrypted(), PRIVKEY_SIZE, resolve_slot(), and RMEM_SLOT_DEC_KEY.

Referenced by cmd_pso_decipher(), and read_public_key().

◆ gpg_storage_ready()

bool gpg_storage_ready ( void )

Definition at line 206 of file GpgStorage.cpp.

References s_storage.

Referenced by gpg_export_pubkey_pem(), gpg_generate_key(), gpg_init(), gpg_reset(), and cdc::mod_gpg::GpgModule::init().

◆ gpg_storage_save_aes_key()

bool gpg_storage_save_aes_key	(	const uint8_t *	key,
		size_t	key_len,
		const char *	pin )

Saves the symmetric AES key for PSO:DECIPHER (DO 0xD5).

Parameters

key	AES key bytes (16 or 32).
key_len	Key length (16 or 32).
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 385 of file GpgStorage.cpp.

References AES_KEY_MAGIC, AES_MAX_KEY_SIZE, AES_RECORD_PAYLOAD, AES_TOTAL_SIZE, LOG_I, resolve_slot(), RMEM_SLOT_AES_KEY, save_slot_encrypted(), and TAG.

Referenced by cmd_put_data().

◆ gpg_storage_save_dec_privkey()

bool gpg_storage_save_dec_privkey	(	const uint8_t *	privkey,
		const char *	pin )

Saves a DEC private key into R-Memory using PIN-bound AES-GCM.

Parameters

privkey	32-byte P-256 private key scalar.
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 347 of file GpgStorage.cpp.

References DEC_KEY_MAGIC, DEC_TOTAL_SIZE, LOG_I, PRIVKEY_SIZE, resolve_slot(), RMEM_SLOT_DEC_KEY, save_slot_encrypted(), and TAG.

Referenced by cmd_put_data_odd(), generate_dec_key(), and gpg_generate_key().

◆ gpg_storage_set_rmem_range()

void gpg_storage_set_rmem_range	(	uint16_t	rmemStart,
		uint16_t	rmemEnd )

Definition at line 201 of file GpgStorage.cpp.

References s_storage.

Referenced by cdc::mod_gpg::GpgModule::init().

◆ gpg_storage_set_session_pin()

void gpg_storage_set_session_pin ( const char * pin )

Stores session PIN-derived key after successful PIN verification.

Parameters

pin	Verified PIN string.

Definition at line 446 of file GpgStorage.cpp.

References gpg_storage_clear_session(), pin_to_hash(), and s_storage.

Referenced by cmd_verify().

◆ gpg_storage_set_slot_range()

void gpg_storage_set_slot_range	(	uint16_t	eccStart,
		uint16_t	eccEnd )

Definition at line 186 of file GpgStorage.cpp.

References s_storage.

Referenced by cdc::mod_gpg::GpgModule::init().

◆ gpg_storage_sig_slot()

uint8_t gpg_storage_sig_slot ( void )

Definition at line 207 of file GpgStorage.cpp.

References s_storage.

Referenced by cmd_get_data(), cmd_pso_cds(), get_ecc_slot_for_key_ref(), gpg_alchemy_fingerprint(), gpg_export_pubkey_pem(), gpg_generate_key(), cdc::mod_gpg::gpgCrossSign(), openpgp_factory_reset(), and put_data_algo_attr().

◆ load_slot_decrypted()

bool load_slot_decrypted	(	uint16_t	slot_id,
		const uint8_t	magic[MAGIC_SIZE],
		uint8_t *	payload_out,
		size_t	payload_len,
		const char *	pin )

static

Reads and decrypts a payload from a slot.

Parameters

slot_id	Absolute R-Memory slot.
magic	4-byte magic marker.
payload_out	Output buffer.
payload_len	Expected plaintext length.
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 290 of file GpgStorage.cpp.

References cdc::core::aesGcm256Open(), build_aad(), derive_storage_key(), get_se(), MAGIC_SIZE, NONCE_SIZE, cdc::hal::OK, pin_to_hash(), and TAG_SIZE.

Referenced by gpg_storage_load_aes_key(), and gpg_storage_load_dec_privkey().

◆ pin_to_hash()

bool pin_to_hash	(	const char *	pin,
		uint8_t *	hash_out )

static

Computes SHA-256 over a PIN string.

Parameters

pin	PIN string; may be empty/nullptr.
hash_out	32-byte output buffer.

Returns: true on success.

Definition at line 115 of file GpgStorage.cpp.

Referenced by gpg_storage_set_session_pin(), load_slot_decrypted(), and save_slot_encrypted().

◆ resolve_slot()

uint16_t resolve_slot ( uint16_t rel_index )

static

Resolves an absolute R-Memory slot index relative to the module range.

Parameters

rel_index Offset within the module range.

Returns: Absolute slot index.

Definition at line 182 of file GpgStorage.cpp.

References s_storage.

Referenced by gpg_storage_delete_aes_key(), gpg_storage_delete_dec_privkey(), gpg_storage_has_aes_key(), gpg_storage_has_dec_privkey(), gpg_storage_load_aes_key(), gpg_storage_load_dec_privkey(), gpg_storage_save_aes_key(), and gpg_storage_save_dec_privkey().

◆ save_slot_encrypted()

bool save_slot_encrypted	(	uint16_t	slot_id,
		const uint8_t	magic[MAGIC_SIZE],
		const uint8_t *	payload,
		size_t	payload_len,
		uint8_t *	record_buf,
		size_t	record_buf_len,
		const char *	pin )

static

Encrypts and writes an arbitrary payload to a slot.

Parameters

slot_id	Absolute R-Memory slot.
magic	4-byte magic marker.
payload	Plaintext bytes.
payload_len	Plaintext length.
record_buf	Scratch buffer; must hold MAGIC + NONCE + payload_len + TAG.
record_buf_len	Length of record_buf.
pin	Session PIN; nullptr falls back to chip-bound key.

Returns: true on success.

Definition at line 222 of file GpgStorage.cpp.

References cdc::core::aesGcm256Seal(), build_aad(), derive_storage_key(), get_se(), LOG_E, MAGIC_SIZE, NONCE_SIZE, cdc::hal::OK, pin_to_hash(), TAG, and TAG_SIZE.

Referenced by gpg_storage_save_aes_key(), and gpg_storage_save_dec_privkey().

Variable Documentation

◆ AES_KEY_MAGIC

uint8_t AES_KEY_MAGIC[4] = {'A', 'E', 'S', '1'}

staticconstexpr

Magic marker for symmetric AES key records (DO 0xD5).

Definition at line 36 of file GpgStorage.cpp.

Referenced by gpg_storage_has_aes_key(), gpg_storage_load_aes_key(), and gpg_storage_save_aes_key().

◆ AES_MAX_KEY_SIZE

size_t AES_MAX_KEY_SIZE = 32

staticconstexpr

Definition at line 42 of file GpgStorage.cpp.

Referenced by gpg_storage_save_aes_key().

◆ AES_RECORD_PAYLOAD

size_t AES_RECORD_PAYLOAD = 1 + AES_MAX_KEY_SIZE

staticconstexpr

Definition at line 44 of file GpgStorage.cpp.

Referenced by gpg_storage_load_aes_key(), and gpg_storage_save_aes_key().

◆ AES_TOTAL_SIZE

size_t AES_TOTAL_SIZE = MAGIC_SIZE + NONCE_SIZE + AES_RECORD_PAYLOAD + TAG_SIZE

staticconstexpr

Definition at line 45 of file GpgStorage.cpp.

Referenced by gpg_storage_save_aes_key().

◆ DEC_KEY_MAGIC

uint8_t DEC_KEY_MAGIC[4] = {'E', 'C', 'D', 'H'}

staticconstexpr

Magic marker for encrypted DEC private key records.

Definition at line 33 of file GpgStorage.cpp.

Referenced by gpg_storage_has_dec_privkey(), gpg_storage_load_dec_privkey(), and gpg_storage_save_dec_privkey().

◆ DEC_TOTAL_SIZE

size_t DEC_TOTAL_SIZE = MAGIC_SIZE + NONCE_SIZE + PRIVKEY_SIZE + TAG_SIZE

staticconstexpr

Definition at line 43 of file GpgStorage.cpp.

Referenced by gpg_storage_has_dec_privkey(), and gpg_storage_save_dec_privkey().

◆ HKDF_INFO

char HKDF_INFO[] = "GPG-STORAGE-V2"

staticconstexpr

HKDF info string for storage key derivation.

Definition at line 48 of file GpgStorage.cpp.

Referenced by derive_storage_key().

◆ MAGIC_SIZE

size_t MAGIC_SIZE = 4

staticconstexpr

Definition at line 38 of file GpgStorage.cpp.

Referenced by build_aad(), gpg_storage_has_aes_key(), gpg_storage_has_dec_privkey(), load_slot_decrypted(), and save_slot_encrypted().

◆ NONCE_SIZE

size_t NONCE_SIZE = 12

staticconstexpr

Definition at line 39 of file GpgStorage.cpp.

Referenced by load_slot_decrypted(), and save_slot_encrypted().

◆ PRIVKEY_SIZE

size_t PRIVKEY_SIZE = 32

staticconstexpr

Definition at line 41 of file GpgStorage.cpp.

Referenced by gpg_storage_load_dec_privkey(), and gpg_storage_save_dec_privkey().

◆ RMEM_SLOT_AES_KEY

uint16_t RMEM_SLOT_AES_KEY = 2

staticconstexpr

R-Memory slot offset for the symmetric AES key payload (= ECC slot 3).

Definition at line 30 of file GpgStorage.cpp.

Referenced by gpg_storage_delete_aes_key(), gpg_storage_has_aes_key(), gpg_storage_load_aes_key(), and gpg_storage_save_aes_key().

◆ RMEM_SLOT_DEC_KEY

uint16_t RMEM_SLOT_DEC_KEY = 1

staticconstexpr

R-Memory slot offset for the DEC private key payload (= ECC slot 2).

Definition at line 27 of file GpgStorage.cpp.

Referenced by gpg_storage_delete_dec_privkey(), gpg_storage_has_dec_privkey(), gpg_storage_load_dec_privkey(), and gpg_storage_save_dec_privkey().

◆ []

struct { ... } s_storage

Referenced by gpg_storage_aut_slot(), gpg_storage_clear_session(), gpg_storage_dec_slot(), gpg_storage_get_session_key(), gpg_storage_ready(), gpg_storage_set_rmem_range(), gpg_storage_set_session_pin(), gpg_storage_set_slot_range(), gpg_storage_sig_slot(), and resolve_slot().

◆ TAG

const char* TAG = "GPGStorage"

static

Encrypted persistent storage for OpenPGP secret material.

Encrypts payloads with AES-256-GCM. The wrapping key is derived via HKDF over (chip_id || pin_hash) with the slot index appended; AAD binds the record to (slot_id, magic) to defeat slot-shuffle attacks.

Definition at line 20 of file GpgStorage.cpp.

◆ TAG_SIZE

size_t TAG_SIZE = 16

staticconstexpr

Definition at line 40 of file GpgStorage.cpp.

Referenced by load_slot_decrypted(), and save_slot_encrypted().

Classes

Namespaces

Functions

Variables

Function Documentation

◆ build_aad()

◆ derive_storage_key()

◆ get_se()

◆ gpg_storage_aut_slot()

◆ gpg_storage_clear_session()

◆ gpg_storage_dec_slot()

◆ gpg_storage_delete_aes_key()

◆ gpg_storage_delete_dec_privkey()

◆ gpg_storage_get_session_key()

◆ gpg_storage_has_aes_key()

◆ gpg_storage_has_dec_privkey()

◆ gpg_storage_load_aes_key()

◆ gpg_storage_load_dec_privkey()

◆ gpg_storage_ready()

◆ gpg_storage_save_aes_key()

◆ gpg_storage_save_dec_privkey()

◆ gpg_storage_set_rmem_range()

◆ gpg_storage_set_session_pin()

◆ gpg_storage_set_slot_range()

◆ gpg_storage_sig_slot()

◆ load_slot_decrypted()

◆ pin_to_hash()

◆ resolve_slot()

◆ save_slot_encrypted()

Variable Documentation

◆ AES_KEY_MAGIC

◆ AES_MAX_KEY_SIZE

◆ AES_RECORD_PAYLOAD

◆ AES_TOTAL_SIZE

◆ DEC_KEY_MAGIC

◆ DEC_TOTAL_SIZE

◆ HKDF_INFO

◆ MAGIC_SIZE

◆ NONCE_SIZE

◆ PRIVKEY_SIZE

◆ RMEM_SLOT_AES_KEY

◆ RMEM_SLOT_DEC_KEY

◆ []

◆ TAG

◆ TAG_SIZE