-/**
- * @file decaf/point_448.h
- * @author Mike Hamburg
+/*
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2015-2016 Cryptography Research, Inc.
*
- * @copyright
- * Copyright (c) 2015-2016 Cryptography Research, Inc. \n
- * Released under the MIT License. See LICENSE.txt for license information.
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*
- * @brief A group of prime order p, based on Ed448-Goldilocks.
- *
- * @warning This file was automatically generated in Python.
- * Please do not edit it.
+ * Originally written by Mike Hamburg
*/
-#ifndef __DECAF_POINT_448_H__
-#define __DECAF_POINT_448_H__ 1
-
-#include "curve448utils.h"
-#include "field.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
+#ifndef HEADER_POINT_448_H
+# define HEADER_POINT_448_H
-/** @cond internal */
-#define DECAF_448_SCALAR_LIMBS ((446-1)/DECAF_WORD_BITS+1)
-/** @endcond */
+# include "curve448utils.h"
+# include "field.h"
-/** The number of bits in a scalar */
-#define DECAF_448_SCALAR_BITS 446
+/* Comb config: number of combs, n, t, s. */
+#define COMBS_N 5
+#define COMBS_T 5
+#define COMBS_S 18
-/** Number of bytes in a serialized point. */
-#define DECAF_448_SER_BYTES 56
+/* Projective Niels coordinates */
+typedef struct {
+ gf a, b, c;
+} niels_s, niels_t[1];
+typedef struct {
+ niels_t n;
+ gf z;
+} pniels_t[1];
-/** Number of bytes in an elligated point. For now set the same as SER_BYTES
- * but could be different for other curves.
- */
-#define DECAF_448_HASH_BYTES 56
-
-/** Number of bytes in a serialized scalar. */
-#define DECAF_448_SCALAR_BYTES 56
+/* Precomputed base */
+struct curve448_precomputed_s {
+ niels_t table[COMBS_N << (COMBS_T - 1)];
+};
-/** Number of bits in the "which" field of an elligator inverse */
-#define DECAF_448_INVERT_ELLIGATOR_WHICH_BITS 3
+# define C448_SCALAR_LIMBS ((446-1)/C448_WORD_BITS+1)
-/** The cofactor the curve would have, if we hadn't removed it */
-#define DECAF_448_REMOVED_COFACTOR 4
+/* The number of bits in a scalar */
+# define C448_SCALAR_BITS 446
-/** X448 encoding ratio. */
-#define DECAF_X448_ENCODE_RATIO 2
+/* Number of bytes in a serialized scalar. */
+# define C448_SCALAR_BYTES 56
-/** Number of bytes in an x448 public key */
-#define DECAF_X448_PUBLIC_BYTES 56
+/* X448 encoding ratio. */
+# define X448_ENCODE_RATIO 2
-/** Number of bytes in an x448 private key */
-#define DECAF_X448_PRIVATE_BYTES 56
+/* Number of bytes in an x448 public key */
+# define X448_PUBLIC_BYTES 56
-/** Twisted Edwards extended homogeneous coordinates */
-typedef struct decaf_448_point_s {
- /** @cond internal */
- gf_448_t x,y,z,t;
- /** @endcond */
-} decaf_448_point_t[1];
+/* Number of bytes in an x448 private key */
+# define X448_PRIVATE_BYTES 56
-/** Precomputed table based on a point. Can be trivial implementation. */
-struct decaf_448_precomputed_s;
+/* Twisted Edwards extended homogeneous coordinates */
+typedef struct curve448_point_s {
+ gf x, y, z, t;
+} curve448_point_t[1];
-/** Precomputed table based on a point. Can be trivial implementation. */
-typedef struct decaf_448_precomputed_s decaf_448_precomputed_s;
+/* Precomputed table based on a point. Can be trivial implementation. */
+struct curve448_precomputed_s;
-/** Scalar is stored packed, because we don't need the speed. */
-typedef struct decaf_448_scalar_s {
- /** @cond internal */
- decaf_word_t limb[DECAF_448_SCALAR_LIMBS];
- /** @endcond */
-} decaf_448_scalar_t[1];
+/* Precomputed table based on a point. Can be trivial implementation. */
+typedef struct curve448_precomputed_s curve448_precomputed_s;
-/** A scalar equal to 1. */
-extern const decaf_448_scalar_t decaf_448_scalar_one DECAF_API_VIS;
+/* Scalar is stored packed, because we don't need the speed. */
+typedef struct curve448_scalar_s {
+ c448_word_t limb[C448_SCALAR_LIMBS];
+} curve448_scalar_t[1];
-/** A scalar equal to 0. */
-extern const decaf_448_scalar_t decaf_448_scalar_zero DECAF_API_VIS;
+/* A scalar equal to 1. */
+extern const curve448_scalar_t curve448_scalar_one;
-/** The identity point on the curve. */
-extern const decaf_448_point_t decaf_448_point_identity DECAF_API_VIS;
+/* A scalar equal to 0. */
+extern const curve448_scalar_t curve448_scalar_zero;
-/** An arbitrarily chosen base point on the curve. */
-extern const decaf_448_point_t decaf_448_point_base DECAF_API_VIS;
+/* The identity point on the curve. */
+extern const curve448_point_t curve448_point_identity;
-/** Precomputed table for the base point on the curve. */
-extern const struct decaf_448_precomputed_s *decaf_448_precomputed_base DECAF_API_VIS;
+/* Precomputed table for the base point on the curve. */
+extern const struct curve448_precomputed_s *curve448_precomputed_base;
+extern const niels_t *curve448_wnaf_base;
-/**
- * @brief Read a scalar from wire format or from bytes.
+/*
+ * Read a scalar from wire format or from bytes.
*
- * @param [in] ser Serialized form of a scalar.
- * @param [out] out Deserialized form.
+ * ser (in): Serialized form of a scalar.
+ * out (out): Deserialized form.
*
- * @retval DECAF_SUCCESS The scalar was correctly encoded.
- * @retval DECAF_FAILURE The scalar was greater than the modulus,
- * and has been reduced modulo that modulus.
+ * Returns:
+ * C448_SUCCESS: The scalar was correctly encoded.
+ * C448_FAILURE: The scalar was greater than the modulus, and has been reduced
+ * modulo that modulus.
*/
-decaf_error_t decaf_448_scalar_decode (
- decaf_448_scalar_t out,
- const unsigned char ser[DECAF_448_SCALAR_BYTES]
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Read a scalar from wire format or from bytes. Reduces mod
- * scalar prime.
+c448_error_t curve448_scalar_decode(curve448_scalar_t out,
+ const unsigned char ser[C448_SCALAR_BYTES]);
+
+/*
+ * Read a scalar from wire format or from bytes. Reduces mod scalar prime.
*
- * @param [in] ser Serialized form of a scalar.
- * @param [in] ser_len Length of serialized form.
- * @param [out] out Deserialized form.
+ * ser (in): Serialized form of a scalar.
+ * ser_len (in): Length of serialized form.
+ * out (out): Deserialized form.
*/
-void decaf_448_scalar_decode_long (
- decaf_448_scalar_t out,
- const unsigned char *ser,
- size_t ser_len
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Serialize a scalar to wire format.
+void curve448_scalar_decode_long(curve448_scalar_t out,
+ const unsigned char *ser, size_t ser_len);
+
+/*
+ * Serialize a scalar to wire format.
*
- * @param [out] ser Serialized form of a scalar.
- * @param [in] s Deserialized scalar.
+ * ser (out): Serialized form of a scalar.
+ * s (in): Deserialized scalar.
+ */
+void curve448_scalar_encode(unsigned char ser[C448_SCALAR_BYTES],
+ const curve448_scalar_t s);
+
+/*
+ * Add two scalars. |a|, |b| and |out| may alias each other.
+ *
+ * a (in): One scalar.
+ * b (in): Another scalar.
+ * out (out): a+b.
+ */
+void curve448_scalar_add(curve448_scalar_t out,
+ const curve448_scalar_t a, const curve448_scalar_t b);
+
+/*
+ * Subtract two scalars. |a|, |b| and |out| may alias each other.
+ * a (in): One scalar.
+ * b (in): Another scalar.
+ * out (out): a-b.
*/
-void decaf_448_scalar_encode (
- unsigned char ser[DECAF_448_SCALAR_BYTES],
- const decaf_448_scalar_t s
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE DECAF_NOINLINE;
-
-/**
- * @brief Add two scalars. The scalars may use the same memory.
- * @param [in] a One scalar.
- * @param [in] b Another scalar.
- * @param [out] out a+b.
+void curve448_scalar_sub(curve448_scalar_t out,
+ const curve448_scalar_t a, const curve448_scalar_t b);
+
+/*
+ * Multiply two scalars. |a|, |b| and |out| may alias each other.
+ *
+ * a (in): One scalar.
+ * b (in): Another scalar.
+ * out (out): a*b.
*/
-void decaf_448_scalar_add (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a,
- const decaf_448_scalar_t b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Compare two scalars.
- * @param [in] a One scalar.
- * @param [in] b Another scalar.
- * @retval DECAF_TRUE The scalars are equal.
- * @retval DECAF_FALSE The scalars are not equal.
- */
-decaf_bool_t decaf_448_scalar_eq (
- const decaf_448_scalar_t a,
- const decaf_448_scalar_t b
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Subtract two scalars. The scalars may use the same memory.
- * @param [in] a One scalar.
- * @param [in] b Another scalar.
- * @param [out] out a-b.
- */
-void decaf_448_scalar_sub (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a,
- const decaf_448_scalar_t b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Multiply two scalars. The scalars may use the same memory.
- * @param [in] a One scalar.
- * @param [in] b Another scalar.
- * @param [out] out a*b.
- */
-void decaf_448_scalar_mul (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a,
- const decaf_448_scalar_t b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
-* @brief Halve a scalar. The scalars may use the same memory.
-* @param [in] a A scalar.
-* @param [out] out a/2.
+void curve448_scalar_mul(curve448_scalar_t out,
+ const curve448_scalar_t a, const curve448_scalar_t b);
+
+/*
+* Halve a scalar. |a| and |out| may alias each other.
+*
+* a (in): A scalar.
+* out (out): a/2.
*/
-void decaf_448_scalar_halve (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Invert a scalar. When passed zero, return 0. The input and output may alias.
- * @param [in] a A scalar.
- * @param [out] out 1/a.
- * @return DECAF_SUCCESS The input is nonzero.
- */
-decaf_error_t decaf_448_scalar_invert (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Copy a scalar. The scalars may use the same memory, in which
- * case this function does nothing.
- * @param [in] a A scalar.
- * @param [out] out Will become a copy of a.
+void curve448_scalar_halve(curve448_scalar_t out, const curve448_scalar_t a);
+
+/*
+ * Copy a scalar. The scalars may use the same memory, in which case this
+ * function does nothing.
+ *
+ * a (in): A scalar.
+ * out (out): Will become a copy of a.
*/
-static inline void DECAF_NONNULL decaf_448_scalar_copy (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a
-) {
+static ossl_inline void curve448_scalar_copy(curve448_scalar_t out,
+ const curve448_scalar_t a)
+{
*out = *a;
}
-/**
- * @brief Set a scalar to an unsigned 64-bit integer.
- * @param [in] a An integer.
- * @param [out] out Will become equal to a.
- */
-void decaf_448_scalar_set_unsigned (
- decaf_448_scalar_t out,
- uint64_t a
-) DECAF_API_VIS DECAF_NONNULL;
-
-/**
- * @brief Copy a point. The input and output may alias,
- * in which case this function does nothing.
+/*
+ * Copy a point. The input and output may alias, in which case this function
+ * does nothing.
*
- * @param [out] a A copy of the point.
- * @param [in] b Any point.
+ * a (out): A copy of the point.
+ * b (in): Any point.
*/
-static inline void DECAF_NONNULL decaf_448_point_copy (
- decaf_448_point_t a,
- const decaf_448_point_t b
-) {
- *a=*b;
+static ossl_inline void curve448_point_copy(curve448_point_t a,
+ const curve448_point_t b)
+{
+ *a = *b;
}
-/**
- * @brief Test whether two points are equal. If yes, return
- * DECAF_TRUE, else return DECAF_FALSE.
+/*
+ * Test whether two points are equal. If yes, return C448_TRUE, else return
+ * C448_FALSE.
*
- * @param [in] a A point.
- * @param [in] b Another point.
- * @retval DECAF_TRUE The points are equal.
- * @retval DECAF_FALSE The points are not equal.
+ * a (in): A point.
+ * b (in): Another point.
+ *
+ * Returns:
+ * C448_TRUE: The points are equal.
+ * C448_FALSE: The points are not equal.
*/
-decaf_bool_t decaf_448_point_eq (
- const decaf_448_point_t a,
- const decaf_448_point_t b
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Double a point. Equivalent to
- * decaf_448_point_add(two_a,a,a), but potentially faster.
+__owur c448_bool_t curve448_point_eq(const curve448_point_t a,
+ const curve448_point_t b);
+
+/*
+ * Double a point. Equivalent to curve448_point_add(two_a,a,a), but potentially
+ * faster.
*
- * @param [out] two_a The sum a+a.
- * @param [in] a A point.
+ * two_a (out): The sum a+a.
+ * a (in): A point.
*/
-void decaf_448_point_double (
- decaf_448_point_t two_a,
- const decaf_448_point_t a
-) DECAF_API_VIS DECAF_NONNULL;
+void curve448_point_double(curve448_point_t two_a, const curve448_point_t a);
-/**
- * @brief RFC 7748 Diffie-Hellman scalarmul. This function uses a different
+/*
+ * RFC 7748 Diffie-Hellman scalarmul. This function uses a different
* (non-Decaf) encoding.
*
- * @param [out] scaled The scaled point base*scalar
- * @param [in] base The point to be scaled.
- * @param [in] scalar The scalar to multiply by.
+ * out (out): The scaled point base*scalar
+ * base (in): The point to be scaled.
+ * scalar (in): The scalar to multiply by.
*
- * @retval DECAF_SUCCESS The scalarmul succeeded.
- * @retval DECAF_FAILURE The scalarmul didn't succeed, because the base
- * point is in a small subgroup.
+ * Returns:
+ * C448_SUCCESS: The scalarmul succeeded.
+ * C448_FAILURE: The scalarmul didn't succeed, because the base point is in a
+ * small subgroup.
*/
-decaf_error_t decaf_x448 (
- uint8_t out[DECAF_X448_PUBLIC_BYTES],
- const uint8_t base[DECAF_X448_PUBLIC_BYTES],
- const uint8_t scalar[DECAF_X448_PRIVATE_BYTES]
-) DECAF_API_VIS DECAF_NONNULL DECAF_WARN_UNUSED DECAF_NOINLINE;
-
-/**
- * @brief Multiply a point by DECAF_X448_ENCODE_RATIO,
- * then encode it like RFC 7748.
+__owur c448_error_t x448_int(uint8_t out[X448_PUBLIC_BYTES],
+ const uint8_t base[X448_PUBLIC_BYTES],
+ const uint8_t scalar[X448_PRIVATE_BYTES]);
+
+/*
+ * Multiply a point by X448_ENCODE_RATIO, then encode it like RFC 7748.
*
* This function is mainly used internally, but is exported in case
* it will be useful.
*
* The ratio is necessary because the internal representation doesn't
* track the cofactor information, so on output we must clear the cofactor.
- * This would multiply by the cofactor, but in fact internally libdecaf's
- * points are always even, so it multiplies by half the cofactor instead.
+ * This would multiply by the cofactor, but in fact internally points are always
+ * even, so it multiplies by half the cofactor instead.
*
* As it happens, this aligns with the base point definitions; that is,
* if you pass the Decaf/Ristretto base point to this function, the result
- * will be DECAF_X448_ENCODE_RATIO times the X448
+ * will be X448_ENCODE_RATIO times the X448
* base point.
*
- * @param [out] out The scaled and encoded point.
- * @param [in] p The point to be scaled and encoded.
+ * out (out): The scaled and encoded point.
+ * p (in): The point to be scaled and encoded.
*/
-void decaf_448_point_mul_by_ratio_and_encode_like_x448 (
- uint8_t out[DECAF_X448_PUBLIC_BYTES],
- const decaf_448_point_t p
-) DECAF_API_VIS DECAF_NONNULL;
-
-/** The base point for X448 Diffie-Hellman */
-extern const uint8_t decaf_x448_base_point[DECAF_X448_PUBLIC_BYTES] DECAF_API_VIS;
-
-/**
- * @brief RFC 7748 Diffie-Hellman base point scalarmul. This function uses
- * a different (non-Decaf) encoding.
- *
- * Does exactly the same thing as decaf_x448_generate_key,
- * but has a better name.
- *
- * @param [out] scaled The scaled point base*scalar
- * @param [in] scalar The scalar to multiply by.
- */
-void decaf_x448_derive_public_key (
- uint8_t out[DECAF_X448_PUBLIC_BYTES],
- const uint8_t scalar[DECAF_X448_PRIVATE_BYTES]
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/* FUTURE: uint8_t decaf_448_encode_like_curve448) */
-
-/**
- * @brief Precompute a table for fast scalar multiplication.
- * Some implementations do not include precomputed points; for
- * those implementations, this implementation simply copies the
- * point.
- *
- * @param [out] a A precomputed table of multiples of the point.
- * @param [in] b Any point.
+void curve448_point_mul_by_ratio_and_encode_like_x448(
+ uint8_t out[X448_PUBLIC_BYTES],
+ const curve448_point_t p);
+
+/*
+ * RFC 7748 Diffie-Hellman base point scalarmul. This function uses a different
+ * (non-Decaf) encoding.
+ *
+ * out (out): The scaled point base*scalar
+ * scalar (in): The scalar to multiply by.
*/
-void decaf_448_precompute (
- decaf_448_precomputed_s *a,
- const decaf_448_point_t b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Multiply a precomputed base point by a scalar:
- * scaled = scalar*base.
- * Some implementations do not include precomputed points; for
- * those implementations, this function is the same as
- * decaf_448_point_scalarmul
+void x448_derive_public_key(uint8_t out[X448_PUBLIC_BYTES],
+ const uint8_t scalar[X448_PRIVATE_BYTES]);
+
+/*
+ * Multiply a precomputed base point by a scalar: out = scalar*base.
*
- * @param [out] scaled The scaled point base*scalar
- * @param [in] base The point to be scaled.
- * @param [in] scalar The scalar to multiply by.
+ * scaled (out): The scaled point base*scalar
+ * base (in): The point to be scaled.
+ * scalar (in): The scalar to multiply by.
*/
-void decaf_448_precomputed_scalarmul (
- decaf_448_point_t scaled,
- const decaf_448_precomputed_s *base,
- const decaf_448_scalar_t scalar
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
+void curve448_precomputed_scalarmul(curve448_point_t scaled,
+ const curve448_precomputed_s * base,
+ const curve448_scalar_t scalar);
-/**
- * @brief Multiply two base points by two scalars:
- * scaled = scalar1*decaf_448_point_base + scalar2*base2.
+/*
+ * Multiply two base points by two scalars:
+ * combo = scalar1*curve448_point_base + scalar2*base2.
*
- * Otherwise equivalent to decaf_448_point_double_scalarmul, but may be
+ * Otherwise equivalent to curve448_point_double_scalarmul, but may be
* faster at the expense of being variable time.
*
- * @param [out] combo The linear combination scalar1*base + scalar2*base2.
- * @param [in] scalar1 A first scalar to multiply by.
- * @param [in] base2 A second point to be scaled.
- * @param [in] scalar2 A second scalar to multiply by.
- *
- * @warning: This function takes variable time, and may leak the scalars
- * used. It is designed for signature verification.
- */
-void decaf_448_base_double_scalarmul_non_secret (
- decaf_448_point_t combo,
- const decaf_448_scalar_t scalar1,
- const decaf_448_point_t base2,
- const decaf_448_scalar_t scalar2
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Constant-time decision between two scalars. If pick_b
- * is zero, out = a; else out = b.
- *
- * @param [out] out The output. It may be the same as either input.
- * @param [in] a Any scalar.
- * @param [in] b Any scalar.
- * @param [in] pick_b If nonzero, choose scalar b.
- */
-void decaf_448_scalar_cond_sel (
- decaf_448_scalar_t out,
- const decaf_448_scalar_t a,
- const decaf_448_scalar_t b,
- decaf_word_t pick_b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Test that a point is valid, for debugging purposes.
+ * combo (out): The linear combination scalar1*base + scalar2*base2.
+ * scalar1 (in): A first scalar to multiply by.
+ * base2 (in): A second point to be scaled.
+ * scalar2 (in) A second scalar to multiply by.
*
- * @param [in] to_test The point to test.
- * @retval DECAF_TRUE The point is valid.
- * @retval DECAF_FALSE The point is invalid.
+ * Warning: This function takes variable time, and may leak the scalars used.
+ * It is designed for signature verification.
*/
-decaf_bool_t decaf_448_point_valid (
- const decaf_448_point_t to_test
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
+void curve448_base_double_scalarmul_non_secret(curve448_point_t combo,
+ const curve448_scalar_t scalar1,
+ const curve448_point_t base2,
+ const curve448_scalar_t scalar2);
-/**
- * @brief Almost-Elligator-like hash to curve.
- *
- * Call this function with the output of a hash to make a hash to the curve.
- *
- * This function runs Elligator2 on the decaf_448 Jacobi quartic model. It then
- * uses the isogeny to put the result in twisted Edwards form. As a result,
- * it is safe (cannot produce points of order 4), and would be compatible with
- * hypothetical other implementations of Decaf using a Montgomery or untwisted
- * Edwards model.
- *
- * Unlike Elligator, this function may be up to 4:1 on [0,(p-1)/2]:
- * A factor of 2 due to the isogeny.
- * A factor of 2 because we quotient out the 2-torsion.
+/*
+ * Test that a point is valid, for debugging purposes.
*
- * This makes it about 8:1 overall, or 16:1 overall on curves with cofactor 8.
+ * to_test (in): The point to test.
*
- * Negating the input (mod q) results in the same point. Inverting the input
- * (mod q) results in the negative point. This is the same as Elligator.
- *
- * This function isn't quite indifferentiable from a random oracle.
- * However, it is suitable for many protocols, including SPEKE and SPAKE2 EE.
- * Furthermore, calling it twice with independent seeds and adding the results
- * is indifferentiable from a random oracle.
- *
- * @param [in] hashed_data Output of some hash function.
- * @param [out] pt The data hashed to the curve.
+ * Returns:
+ * C448_TRUE The point is valid.
+ * C448_FALSE The point is invalid.
*/
-void
-decaf_448_point_from_hash_nonuniform (
- decaf_448_point_t pt,
- const unsigned char hashed_data[DECAF_448_HASH_BYTES]
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Indifferentiable hash function encoding to curve.
- *
- * Equivalent to calling decaf_448_point_from_hash_nonuniform twice and adding.
- *
- * @param [in] hashed_data Output of some hash function.
- * @param [out] pt The data hashed to the curve.
- */
-void decaf_448_point_from_hash_uniform (
- decaf_448_point_t pt,
- const unsigned char hashed_data[2*DECAF_448_HASH_BYTES]
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Inverse of elligator-like hash to curve.
- *
- * This function writes to the buffer, to make it so that
- * decaf_448_point_from_hash_nonuniform(buffer) = pt if
- * possible. Since there may be multiple preimages, the
- * "which" parameter chooses between them. To ensure uniform
- * inverse sampling, this function succeeds or fails
- * independently for different "which" values.
- *
- * This function isn't guaranteed to find every possible
- * preimage, but it finds all except a small finite number.
- * In particular, when the number of bits in the modulus isn't
- * a multiple of 8 (i.e. for curve25519), it sets the high bits
- * independently, which enables the generated data to be uniform.
- * But it doesn't add p, so you'll never get exactly p from this
- * function. This might change in the future, especially if
- * we ever support eg Brainpool curves, where this could cause
- * real nonuniformity.
- *
- * @param [out] recovered_hash Encoded data.
- * @param [in] pt The point to encode.
- * @param [in] which A value determining which inverse point
- * to return.
- *
- * @retval DECAF_SUCCESS The inverse succeeded.
- * @retval DECAF_FAILURE The inverse failed.
- */
-decaf_error_t
-decaf_448_invert_elligator_nonuniform (
- unsigned char recovered_hash[DECAF_448_HASH_BYTES],
- const decaf_448_point_t pt,
- uint32_t which
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE DECAF_WARN_UNUSED;
-
-/**
- * @brief Inverse of elligator-like hash to curve.
- *
- * This function writes to the buffer, to make it so that
- * decaf_448_point_from_hash_uniform(buffer) = pt if
- * possible. Since there may be multiple preimages, the
- * "which" parameter chooses between them. To ensure uniform
- * inverse sampling, this function succeeds or fails
- * independently for different "which" values.
- *
- * @param [out] recovered_hash Encoded data.
- * @param [in] pt The point to encode.
- * @param [in] which A value determining which inverse point
- * to return.
- *
- * @retval DECAF_SUCCESS The inverse succeeded.
- * @retval DECAF_FAILURE The inverse failed.
- */
-decaf_error_t
-decaf_448_invert_elligator_uniform (
- unsigned char recovered_hash[2*DECAF_448_HASH_BYTES],
- const decaf_448_point_t pt,
- uint32_t which
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE DECAF_WARN_UNUSED;
-
-/**
- * @brief Overwrite scalar with zeros.
- */
-void decaf_448_scalar_destroy (
- decaf_448_scalar_t scalar
-) DECAF_NONNULL DECAF_API_VIS;
+__owur c448_bool_t curve448_point_valid(const curve448_point_t to_test);
-/**
- * @brief Overwrite point with zeros.
- */
-void decaf_448_point_destroy (
- decaf_448_point_t point
-) DECAF_NONNULL DECAF_API_VIS;
+/* Overwrite scalar with zeros. */
+void curve448_scalar_destroy(curve448_scalar_t scalar);
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
+/* Overwrite point with zeros. */
+void curve448_point_destroy(curve448_point_t point);
-#endif /* __DECAF_POINT_448_H__ */
+#endif /* HEADER_POINT_448_H */