*
* Multiply a curve point with an integer.
*
+ * - `mulgen()`
+ *
+ * Multiply the curve generator with an integer. This may be faster
+ * than the generic `mul()`.
+ *
* - `muladd()`
*
* Multiply two curve points by two integers, and return the sum of
* not the case, then this function returns an error (0).
*
* - The multiplier integer MUST be non-zero and less than the
- * curve subgroup order. If the integer is zero, then an
- * error is reported, but if the integer is not lower than
- * the subgroup order, then the result is indeterminate and an
- * error code is not guaranteed.
+ * curve subgroup order. If this property does not hold, then
+ * the result is indeterminate and an error code is not
+ * guaranteed.
*
* Returned value is 1 on success, 0 on error. On error, the
* contents of `G` are indeterminate.
uint32_t (*mul)(unsigned char *G, size_t Glen,
const unsigned char *x, size_t xlen, int curve);
+ /**
+ * \brief Multiply the generator by an integer.
+ *
+ * The multiplier MUST be non-zero and less than the curve
+ * subgroup order. Results are indeterminate if this property
+ * does not hold.
+ *
+ * \param R output buffer for the point.
+ * \param x multiplier (unsigned big-endian).
+ * \param xlen multiplier length (in bytes).
+ * \param curve curve identifier.
+ * \return encoded result point length (in bytes).
+ */
+ size_t (*mulgen)(unsigned char *R,
+ const unsigned char *x, size_t xlen, int curve);
+
/**
* \brief Multiply two points by two integers and add the
* results.
* infinity" either). If this is not the case, then this
* function returns an error (0).
*
+ * - If the `B` pointer is `NULL`, then the conventional
+ * subgroup generator is used. With some implementations,
+ * this may be faster than providing a pointer to the
+ * generator.
+ *
* - The multiplier integers (`x` and `y`) MUST be non-zero
* and less than the curve subgroup order. If either integer
* is zero, then an error is reported, but if one of them is
* contents of `A` are indeterminate.
*
* \param A first point to multiply.
- * \param B second point to multiply.
+ * \param B second point to multiply (`NULL` for the generator).
* \param len common length of the encoded points (in bytes).
* \param x multiplier for `A` (unsigned big-endian).
* \param xlen length of multiplier for `A` (in bytes).
*/
extern const br_ec_impl br_ec_prime_i31;
+/**
+ * \brief EC implementation "i15".
+ *
+ * This implementation internally uses generic code for modular integers,
+ * with a representation as sequences of 15-bit words. It supports secp256r1,
+ * secp384r1 and secp521r1 (aka NIST curves P-256, P-384 and P-521).
+ */
+extern const br_ec_impl br_ec_prime_i15;
+
+/**
+ * \brief EC implementation "i15" for P-256.
+ *
+ * This implementation uses specialised code for curve secp256r1 (also
+ * known as NIST P-256), with Karatsuba decomposition, and fast modular
+ * reduction thanks to the field modulus special format. Only 32-bit
+ * multiplications are used (with 32-bit results, not 64-bit).
+ */
+extern const br_ec_impl br_ec_p256_i15;
+
/**
* \brief Convert a signature from "raw" to "asn1".
*
const void *hash, size_t hash_len,
const br_ec_public_key *pk, const void *sig, size_t sig_len);
+/**
+ * \brief ECDSA signature generator, "i15" implementation, "asn1" format.
+ *
+ * \see br_ecdsa_sign()
+ *
+ * \param impl EC implementation to use.
+ * \param hf hash function used to process the data.
+ * \param hash_value signed data (hashed).
+ * \param sk EC private key.
+ * \param sig destination buffer.
+ * \return the signature length (in bytes), or 0 on error.
+ */
+size_t br_ecdsa_i15_sign_asn1(const br_ec_impl *impl,
+ const br_hash_class *hf, const void *hash_value,
+ const br_ec_private_key *sk, void *sig);
+
+/**
+ * \brief ECDSA signature generator, "i15" implementation, "raw" format.
+ *
+ * \see br_ecdsa_sign()
+ *
+ * \param impl EC implementation to use.
+ * \param hf hash function used to process the data.
+ * \param hash_value signed data (hashed).
+ * \param sk EC private key.
+ * \param sig destination buffer.
+ * \return the signature length (in bytes), or 0 on error.
+ */
+size_t br_ecdsa_i15_sign_raw(const br_ec_impl *impl,
+ const br_hash_class *hf, const void *hash_value,
+ const br_ec_private_key *sk, void *sig);
+
+/**
+ * \brief ECDSA signature verifier, "i15" implementation, "asn1" format.
+ *
+ * \see br_ecdsa_vrfy()
+ *
+ * \param impl EC implementation to use.
+ * \param hash signed data (hashed).
+ * \param hash_len hash value length (in bytes).
+ * \param pk EC public key.
+ * \param sig signature.
+ * \param sig_len signature length (in bytes).
+ * \return 1 on success, 0 on error.
+ */
+uint32_t br_ecdsa_i15_vrfy_asn1(const br_ec_impl *impl,
+ const void *hash, size_t hash_len,
+ const br_ec_public_key *pk, const void *sig, size_t sig_len);
+
+/**
+ * \brief ECDSA signature verifier, "i15" implementation, "raw" format.
+ *
+ * \see br_ecdsa_vrfy()
+ *
+ * \param impl EC implementation to use.
+ * \param hash signed data (hashed).
+ * \param hash_len hash value length (in bytes).
+ * \param pk EC public key.
+ * \param sig signature.
+ * \param sig_len signature length (in bytes).
+ * \return 1 on success, 0 on error.
+ */
+uint32_t br_ecdsa_i15_vrfy_raw(const br_ec_impl *impl,
+ const void *hash, size_t hash_len,
+ const br_ec_public_key *pk, const void *sig, size_t sig_len);
+
#endif
projects / BearSSL / blobdiff