/*
- * Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
* Copyright 2015-2016 Cryptography Research, Inc.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* Originally written by Mike Hamburg
*/
-#ifndef __DECAF_POINT_448_H__
-# define __DECAF_POINT_448_H__ 1
+#ifndef HEADER_POINT_448_H
+# define HEADER_POINT_448_H
# include "curve448utils.h"
# include "field.h"
-#ifdef __cplusplus
-extern "C" {
-#endif
+/* Comb config: number of combs, n, t, s. */
+#define COMBS_N 5
+#define COMBS_T 5
+#define COMBS_S 18
-/** @cond internal */
-# define DECAF_448_SCALAR_LIMBS ((446-1)/DECAF_WORD_BITS+1)
-/** @endcond */
+/* Projective Niels coordinates */
+typedef struct {
+ gf a, b, c;
+} niels_s, niels_t[1];
+typedef struct {
+ niels_t n;
+ gf z;
+} pniels_t[1];
-/** The number of bits in a scalar */
-# define DECAF_448_SCALAR_BITS 446
+/* Precomputed base */
+struct curve448_precomputed_s {
+ niels_t table[COMBS_N << (COMBS_T - 1)];
+};
-/** Number of bytes in a serialized point. */
-# define DECAF_448_SER_BYTES 56
+# define C448_SCALAR_LIMBS ((446-1)/C448_WORD_BITS+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
+/* The number of bits in a scalar */
+# define C448_SCALAR_BITS 446
-/** Number of bits in the "which" field of an elligator inverse */
-# define DECAF_448_INVERT_ELLIGATOR_WHICH_BITS 3
+/* Number of bytes in a serialized scalar. */
+# define C448_SCALAR_BYTES 56
-/** The cofactor the curve would have, if we hadn't removed it */
-# define DECAF_448_REMOVED_COFACTOR 4
+/* X448 encoding ratio. */
+# define X448_ENCODE_RATIO 2
-/** X448 encoding ratio. */
-# define DECAF_X448_ENCODE_RATIO 2
+/* Number of bytes in an x448 public key */
+# define X448_PUBLIC_BYTES 56
-/** Number of bytes in an x448 public key */
-# define DECAF_X448_PUBLIC_BYTES 56
+/* Number of bytes in an x448 private key */
+# define X448_PRIVATE_BYTES 56
-/** Number of bytes in an x448 private key */
-# define DECAF_X448_PRIVATE_BYTES 56
-
-/** Twisted Edwards extended homogeneous coordinates */
+/* Twisted Edwards extended homogeneous coordinates */
typedef struct curve448_point_s {
- /** @cond internal */
- gf_448_t x, y, z, t;
- /** @endcond */
+ gf x, y, z, t;
} curve448_point_t[1];
-/** Precomputed table based on a point. Can be trivial implementation. */
+/* Precomputed table based on a point. Can be trivial implementation. */
struct curve448_precomputed_s;
-/** Precomputed table based on a point. Can be trivial implementation. */
+/* Precomputed table based on a point. Can be trivial implementation. */
typedef struct curve448_precomputed_s curve448_precomputed_s;
-/** Scalar is stored packed, because we don't need the speed. */
+/* Scalar is stored packed, because we don't need the speed. */
typedef struct curve448_scalar_s {
- /** @cond internal */
- decaf_word_t limb[DECAF_448_SCALAR_LIMBS];
- /** @endcond */
+ c448_word_t limb[C448_SCALAR_LIMBS];
} curve448_scalar_t[1];
-/** A scalar equal to 1. */
+/* A scalar equal to 1. */
extern const curve448_scalar_t curve448_scalar_one;
-/** A scalar equal to 0. */
+/* A scalar equal to 0. */
extern const curve448_scalar_t curve448_scalar_zero;
-/** The identity point on the curve. */
+/* The identity point on the curve. */
extern const curve448_point_t curve448_point_identity;
-/** An arbitrarily chosen base point on the curve. */
-extern const curve448_point_t curve448_point_base;
-
-/** Precomputed table for the base point on the curve. */
+/* Precomputed table for the base point on the curve. */
extern const struct curve448_precomputed_s *curve448_precomputed_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.
*/
-__owur decaf_error_t curve448_scalar_decode(curve448_scalar_t out,
- const unsigned char
- ser[DECAF_448_SCALAR_BYTES]
- );
-
-/**
- * @brief Read a scalar from wire format or from bytes. Reduces mod
- * scalar prime.
+__owur 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 curve448_scalar_decode_long(curve448_scalar_t out,
const unsigned char *ser, size_t ser_len);
-/**
- * @brief Serialize a scalar to wire format.
+/*
+ * 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[DECAF_448_SCALAR_BYTES],
+void curve448_scalar_encode(unsigned char ser[C448_SCALAR_BYTES],
const curve448_scalar_t s);
-/**
- * @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.
+/*
+ * 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);
-/**
- * @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.
+/*
+ * Subtract 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_sub(curve448_scalar_t out,
const curve448_scalar_t a, const curve448_scalar_t b);
-/**
- * @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.
+/*
+ * Multiply 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_mul(curve448_scalar_t out,
const curve448_scalar_t a, const curve448_scalar_t b);
-/**
-* @brief Halve a scalar. The scalars may use the same memory.
-* @param [in] a A scalar.
-* @param [out] out a/2.
+/*
+* Halve a scalar. |a| and |out| may alias each other.
+*
+* a (in): A scalar.
+* out (out): a/2.
*/
void curve448_scalar_halve(curve448_scalar_t out, const curve448_scalar_t a);
-/**
- * @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.
+/*
+ * 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 ossl_inline void curve448_scalar_copy(curve448_scalar_t out,
const curve448_scalar_t a)
*out = *a;
}
-/**
- * @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 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.
*/
-__owur decaf_bool_t curve448_point_eq(const curve448_point_t a,
- const curve448_point_t b);
+__owur c448_bool_t curve448_point_eq(const curve448_point_t a,
+ const curve448_point_t b);
-/**
- * @brief Double a point. Equivalent to
- * curve448_point_add(two_a,a,a), but potentially faster.
+/*
+ * 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 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.
*/
-__owur 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]
- );
-
-/**
- * @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 curve448_point_mul_by_ratio_and_encode_like_x448(uint8_t
- out
- [DECAF_X448_PUBLIC_BYTES],
- const curve448_point_t p);
-
-/** The base point for X448 Diffie-Hellman */
-extern const uint8_t decaf_x448_base_point[DECAF_X448_PUBLIC_BYTES];
+void curve448_point_mul_by_ratio_and_encode_like_x448(
+ uint8_t out[X448_PUBLIC_BYTES],
+ const curve448_point_t p);
-/**
- * @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.
+/*
+ * 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_x448_derive_public_key(uint8_t out[DECAF_X448_PUBLIC_BYTES],
- const uint8_t scalar[DECAF_X448_PRIVATE_BYTES]
- );
-
-/**
- * @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
- * curve448_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 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*curve448_point_base + scalar2*base2.
+/*
+ * Multiply two base points by two scalars:
+ * combo = scalar1*curve448_point_base + scalar2*base2.
*
* 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.
+ * 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.
*
- * @warning: This function takes variable time, and may leak the scalars
- * used. It is designed for signature verification.
+ * Warning: This function takes variable time, and may leak the scalars used.
+ * It is designed for signature verification.
*/
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 Test that a point is valid, for debugging purposes.
+/*
+ * Test that a point is valid, for debugging purposes.
*
- * @param [in] to_test The point to test.
- * @retval DECAF_TRUE The point is valid.
- * @retval DECAF_FALSE The point is invalid.
+ * to_test (in): The point to test.
+ *
+ * Returns:
+ * C448_TRUE The point is valid.
+ * C448_FALSE The point is invalid.
*/
-__owur decaf_bool_t curve448_point_valid(const curve448_point_t to_test);
+__owur c448_bool_t curve448_point_valid(const curve448_point_t to_test);
-/**
- * @brief Overwrite scalar with zeros.
- */
+/* Overwrite scalar with zeros. */
void curve448_scalar_destroy(curve448_scalar_t scalar);
-/**
- * @brief Overwrite point with zeros.
- */
+/* Overwrite point with zeros. */
void curve448_point_destroy(curve448_point_t point);
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-#endif /* __DECAF_POINT_448_H__ */
+#endif /* HEADER_POINT_448_H */
projects / openssl.git / blobdiff