CW_CryptoProvider backed by mbedTLS and the ESP32 hardware TRNG. More...

#include <esp32_crypto_provider.h>

Inheritance diagram for ESP32CryptoProvider:

Collaboration diagram for ESP32CryptoProvider:

Public Member Functions
bool	sha256 (const uint8_t data, size_t len, uint8_t out) override
	Compute SHA-256 over a contiguous buffer.
bool	sha512 (const uint8_t data, size_t len, uint8_t out) override
	Compute SHA-512 over a contiguous buffer.
uint16_t	aesCbcEncrypt (const uint8_t in, uint16_t len, uint8_t out, const uint8_t key, uint8_t keyLen, uint8_t iv, bool bitPadding) override
	Encrypt a buffer with AES-CBC.
uint16_t	aesCbcDecrypt (uint8_t in, uint16_t len, uint8_t out, const uint8_t key, uint8_t keyLen, uint8_t iv, bool bitPadding) override
	Decrypt a buffer with AES-CBC.
bool	ecdh (const uint8_t pubKey, const uint8_t privKey, uint8_t *secret, CW_Curve curve) override
	Compute an ECDH shared secret.
bool	makeKey (uint8_t pubKey, uint8_t privKey, CW_Curve curve) override
	Generate an ephemeral EC key pair.
bool	random (uint8_t *dest, unsigned size) override
	Fill a buffer with cryptographically random bytes.
bool	ecdsaVerify (const uint8_t pubKey64, const uint8_t hash, size_t hashLen, const uint8_t *sig, CW_Curve curve) override
	Verify an ECDSA signature.
	~ESP32CryptoProvider () override
	Default destructor.

Detailed Description

CW_CryptoProvider backed by mbedTLS and the ESP32 hardware TRNG.

All operations are stateless; a single instance may be shared across multiple CryptnoxWallet objects (though concurrent use from different RTOS tasks is not thread-safe without external locking).

Warning: See the random method for TRNG entropy requirements (SEC-001).

Example: ESP32CryptoProvider crypto;

CW_CryptoProvider &provider = crypto;

uint8_t pub[64], priv[32];

provider.makeKey(pub, priv, CW_CURVE_SECP256R1); // generate ephemeral key pair

uint8_t digest[32];

provider.sha256(message, messageLen, digest); // hash a message

ESP32CryptoProvider
CW_CryptoProvider backed by mbedTLS and the ESP32 hardware TRNG.
Definition esp32_crypto_provider.h:62

See also: CW_CryptoProvider; CryptnoxWallet

Examples: BasicUsage/main/main.cpp, Connect/main/main.cpp, Sign/main/main.cpp, UsdcSigning/main/main.cpp, and VerifyPin/main/main.cpp.

Definition at line 62 of file esp32_crypto_provider.h.

Constructor & Destructor Documentation

◆ ~ESP32CryptoProvider()

ESP32CryptoProvider::~ESP32CryptoProvider ( )

inlineoverride

Default destructor.

Definition at line 213 of file esp32_crypto_provider.h.

Member Function Documentation

◆ aesCbcDecrypt()

uint16_t ESP32CryptoProvider::aesCbcDecrypt	(	uint8_t *	in,
		uint16_t	len,
		uint8_t *	out,
		const uint8_t *	key,
		uint8_t	keyLen,
		uint8_t *	iv,
		bool	bitPadding )

override

Decrypt a buffer with AES-CBC.

AES-CBC decrypt with optional ISO/IEC 9797-1 Method 2 bit-padding removal.

Uses mbedTLS AES-CBC and optionally strips ISO/IEC 7816-4 bit-padding after decryption. The IV is updated in-place.

Parameters

[in,out]	in	Ciphertext input buffer; may be modified in-place (must not be `NULL`).
[in]	len	Length of `in` in bytes (must be a multiple of 16).
[out]	out	Plaintext output buffer (must not be `NULL`).
[in]	key	AES key bytes (must not be `NULL`).
[in]	keyLen	Key length in bytes (`16` / `24` / `32`).
[in,out]	iv	16-byte IV; updated in-place after the call.
[in]	bitPadding	When `true`, strips ISO/IEC 7816-4 bit padding from the decrypted output.

Returns: Number of plaintext bytes written to out, or 0 on failure.

Definition at line 147 of file esp32_crypto_provider.cpp.

References AES_BLOCK_SIZE_BYTES, AES_KEY_BITS_PER_BYTE, BIT_PADDING_MARKER, MBEDTLS_OK, and PADDING_ZERO_FILL.

◆ aesCbcEncrypt()

uint16_t ESP32CryptoProvider::aesCbcEncrypt	(	const uint8_t *	in,
		uint16_t	len,
		uint8_t *	out,
		const uint8_t *	key,
		uint8_t	keyLen,
		uint8_t *	iv,
		bool	bitPadding )

override

Encrypt a buffer with AES-CBC.

AES-CBC encrypt with optional ISO/IEC 9797-1 Method 2 bit padding.

Uses mbedTLS AES-CBC with optional ISO/IEC 7816-4 bit-padding. The IV is updated in-place after each block so that the caller can chain calls for streaming encryption.

Parameters

[in]	in	Plaintext input buffer (must not be `NULL`).
[in]	len	Length of `in` in bytes.
[out]	out	Ciphertext output buffer; must be at least `len` + 16 bytes to accommodate padding.
[in]	key	AES key bytes (must not be `NULL`).
[in]	keyLen	Key length in bytes (`16` for AES-128, `24` for AES-192, `32` for AES-256).
[in,out]	iv	16-byte IV; updated in-place after the call.
[in]	bitPadding	When `true`, applies ISO/IEC 7816-4 bit padding before encrypting.

Returns: Number of ciphertext bytes written to out, or 0 on failure.

Definition at line 89 of file esp32_crypto_provider.cpp.

References AES_BLOCK_SIZE_BYTES, AES_KEY_BITS_PER_BYTE, AES_PAD_BUF_SIZE, BIT_PADDING_MARKER, MBEDTLS_OK, and PADDING_ZERO_FILL.

◆ ecdh()

bool ESP32CryptoProvider::ecdh	(	const uint8_t *	pubKey,
		const uint8_t *	privKey,
		uint8_t *	secret,
		CW_Curve	curve )

override

Compute an ECDH shared secret.

Compute ECDH shared secret: X-coordinate of privKey * pubKey point.

Performs the standard Diffie-Hellman point multiplication secret = privKey × pubKey on the specified curve via the uECC shim.

Parameters

[in]	pubKey	Uncompressed peer public key (64 bytes, X\|\|Y; no `0x04` prefix; must not be `NULL`).
[in]	privKey	32-byte private scalar (must not be `NULL`).
[out]	secret	32-byte shared-secret output buffer (must not be `NULL`).
[in]	curve	Elliptic curve selector (CW_CURVE_SECP256R1 or CW_CURVE_SECP256K1).

Returns: true on success, false if point multiplication fails or a pointer argument is NULL.

Definition at line 211 of file esp32_crypto_provider.cpp.

References toCurve(), uECC_shared_secret(), and UECC_SUCCESS.

◆ ecdsaVerify()

bool ESP32CryptoProvider::ecdsaVerify	(	const uint8_t *	pubKey64,
		const uint8_t *	hash,
		size_t	hashLen,
		const uint8_t *	sig,
		CW_Curve	curve )

override

Verify an ECDSA signature.

Verify an ECDSA signature (raw r||s) against a hash on the specified curve.

Checks that sig is a valid low-S DER-encoded ECDSA signature over hash produced by the private key corresponding to pubKey64.

Parameters

[in]	pubKey64	64-byte uncompressed public key (X\|\|Y, no `0x04` prefix; must not be `NULL`).
[in]	hash	Message digest to verify against (must not be `NULL`).
[in]	hashLen	Length of `hash` in bytes.
[in]	sig	DER-encoded signature bytes (must not be `NULL`).
[in]	curve	Elliptic curve selector (CW_CURVE_SECP256R1 or CW_CURVE_SECP256K1).

Returns: true if the signature is valid, false otherwise (including on NULL arguments or malformed DER).

Definition at line 250 of file esp32_crypto_provider.cpp.

References toCurve(), UECC_SUCCESS, and uECC_verify().

◆ makeKey()

bool ESP32CryptoProvider::makeKey	(	uint8_t *	pubKey,
		uint8_t *	privKey,
		CW_Curve	curve )

override

Generate an ephemeral EC key pair.

Generate an ECC key pair via mbedTLS and the ESP32 hardware RNG.

Uses the hardware TRNG (via random) as the entropy source for the private scalar.

Parameters

[out]	pubKey	64-byte uncompressed public key output (X\|\|Y, no `0x04` prefix; must not be `NULL`).
[out]	privKey	32-byte private key output (must not be `NULL`).
[in]	curve	Elliptic curve selector (CW_CURVE_SECP256R1 or CW_CURVE_SECP256K1).

Returns: true on success, false on RNG or key-generation failure.

Warning: Ensure Wi-Fi or BT is active before calling this to guarantee full TRNG entropy (SEC-001).

Definition at line 223 of file esp32_crypto_provider.cpp.

References toCurve(), uECC_make_key(), and UECC_SUCCESS.

◆ random()

bool ESP32CryptoProvider::random	(	uint8_t *	dest,
		unsigned	size )

override

Fill a buffer with cryptographically random bytes.

Fill dest with size cryptographically random bytes from the ESP32 hardware RNG.

Calls esp_fill_random() which reads from the ESP32 hardware TRNG. Full entropy requires Wi-Fi or Bluetooth to be active; without a live radio the TRNG operates in reduced-entropy mode (thermal noise and ring-oscillator jitter only — see SEC-001).

Parameters

[out]	dest	Buffer to fill (must not be `NULL`).
[in]	size	Number of random bytes to generate.

Returns: true on success, false if dest is NULL or size is 0.

Warning: In production firmware, call this only after Wi-Fi or BT has been started to ensure full entropy.

Definition at line 239 of file esp32_crypto_provider.cpp.

◆ sha256()

bool ESP32CryptoProvider::sha256	(	const uint8_t *	data,
		size_t	len,
		uint8_t *	out )

override

Compute SHA-256 over a contiguous buffer.

Compute SHA-256 over the input buffer, writing 32 bytes to out.

Uses the mbedTLS mbedtls_sha256 API, which is hardware-accelerated on ESP32-S3.

Parameters

[in]	data	Pointer to the input data (must not be `NULL`).
[in]	len	Length of `data` in bytes.
[out]	out	32-byte output buffer for the digest (must not be `NULL`).

Returns: true on success, false if data or out is NULL or if the mbedTLS call fails.

Definition at line 73 of file esp32_crypto_provider.cpp.

References MBEDTLS_OK, and MBEDTLS_SHA256_MODE.

◆ sha512()

bool ESP32CryptoProvider::sha512	(	const uint8_t *	data,
		size_t	len,
		uint8_t *	out )

override

Compute SHA-512 over a contiguous buffer.

Compute SHA-512 over the input buffer, writing 64 bytes to out.

Uses the mbedTLS mbedtls_sha512 API, which is hardware-accelerated on ESP32-S3.

Parameters

[in]	data	Pointer to the input data (must not be `NULL`).
[in]	len	Length of `data` in bytes.
[out]	out	64-byte output buffer for the digest (must not be `NULL`).

Returns: true on success, false if data or out is NULL or if the mbedTLS call fails.

Definition at line 79 of file esp32_crypto_provider.cpp.

References MBEDTLS_OK, and MBEDTLS_SHA512_MODE.

The documentation for this class was generated from the following files:

components/crypto_provider/include/esp32_crypto_provider.h
components/crypto_provider/esp32_crypto_provider.cpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~ESP32CryptoProvider()

Member Function Documentation

◆ aesCbcDecrypt()

◆ aesCbcEncrypt()

◆ ecdh()

◆ ecdsaVerify()

◆ makeKey()

◆ random()

◆ sha256()

◆ sha512()