Update ecp.h
Reviewed and standardized
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index e024da8..89c756b 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -1,10 +1,20 @@
/**
* \file ecp.h
*
- * \brief Elliptic curves over GF(p)
+ * \brief This file contains ECP definitions and functions.
+ *
+ * The Elliptic Curve over P (ECP) is defined in <em>Standards for Efficient
+ * Cryptography Group (SECG): SEC1 Elliptic Curve Cryptography</em> and
+ * <em>RFC-4492: Elliptic Curve Cryptography (ECC) Cipher Suites
+ * for Transport Layer Security (TLS)</em>.
+ *
+ * <em>RFC-2409: The Internet Key Exchange (IKE)</em> defines ECP
+ * group types.
+ *
*/
-/*
- * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+
+/*
+ * Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -19,8 +29,9 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*
- * This file is part of mbed TLS (https://tls.mbed.org)
+ * This file is part of Mbed TLS (https://tls.mbed.org)
*/
+
#ifndef MBEDTLS_ECP_H
#define MBEDTLS_ECP_H
@@ -31,13 +42,13 @@
*/
#define MBEDTLS_ERR_ECP_BAD_INPUT_DATA -0x4F80 /**< Bad input parameters to function. */
#define MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL -0x4F00 /**< The buffer is too small to write to. */
-#define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE -0x4E80 /**< Requested curve not available. */
+#define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE -0x4E80 /**< The requested curve not available. */
#define MBEDTLS_ERR_ECP_VERIFY_FAILED -0x4E00 /**< The signature is not valid. */
#define MBEDTLS_ERR_ECP_ALLOC_FAILED -0x4D80 /**< Memory allocation failed. */
-#define MBEDTLS_ERR_ECP_RANDOM_FAILED -0x4D00 /**< Generation of random value, such as (ephemeral) key, failed. */
+#define MBEDTLS_ERR_ECP_RANDOM_FAILED -0x4D00 /**< Generation of random value, such as ephemeral key, failed. */
#define MBEDTLS_ERR_ECP_INVALID_KEY -0x4C80 /**< Invalid private or public key. */
#define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH -0x4C00 /**< The buffer contains a valid signature followed by more data. */
-#define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED -0x4B80 /**< ECP hardware accelerator failed. */
+#define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED -0x4B80 /**< The ECP hardware accelerator failed. */
#if !defined(MBEDTLS_ECP_ALT)
/*
@@ -53,9 +64,9 @@
#endif
/**
- * Domain parameters (curve, subgroup and generator) identifiers.
+ * Definition of domain parameter identifiers: curve, subgroup and generator.
*
- * Only curves over prime fields are supported.
+ * \note Only curves over prime fields are supported.
*
* \warning This library does not support validation of arbitrary domain
* parameters. Therefore, only well-known domain parameters from trusted
@@ -63,113 +74,119 @@
*/
typedef enum
{
- MBEDTLS_ECP_DP_NONE = 0,
- MBEDTLS_ECP_DP_SECP192R1, /*!< 192-bits NIST curve */
- MBEDTLS_ECP_DP_SECP224R1, /*!< 224-bits NIST curve */
- MBEDTLS_ECP_DP_SECP256R1, /*!< 256-bits NIST curve */
- MBEDTLS_ECP_DP_SECP384R1, /*!< 384-bits NIST curve */
- MBEDTLS_ECP_DP_SECP521R1, /*!< 521-bits NIST curve */
- MBEDTLS_ECP_DP_BP256R1, /*!< 256-bits Brainpool curve */
- MBEDTLS_ECP_DP_BP384R1, /*!< 384-bits Brainpool curve */
- MBEDTLS_ECP_DP_BP512R1, /*!< 512-bits Brainpool curve */
- MBEDTLS_ECP_DP_CURVE25519, /*!< Curve25519 */
- MBEDTLS_ECP_DP_CURVE448, /*!< Curve448 */
- MBEDTLS_ECP_DP_SECP192K1, /*!< 192-bits "Koblitz" curve */
- MBEDTLS_ECP_DP_SECP224K1, /*!< 224-bits "Koblitz" curve */
- MBEDTLS_ECP_DP_SECP256K1, /*!< 256-bits "Koblitz" curve */
+ MBEDTLS_ECP_DP_NONE = 0, /*!< Curve not defined. */
+ MBEDTLS_ECP_DP_SECP192R1, /*!< Domain parameters for 192-bit NIST curve. */
+ MBEDTLS_ECP_DP_SECP224R1, /*!< Domain parameters for 224-bit NIST curve. */
+ MBEDTLS_ECP_DP_SECP256R1, /*!< Domain parameters for 256-bit NIST curve. */
+ MBEDTLS_ECP_DP_SECP384R1, /*!< Domain parameters for 384-bit NIST curve. */
+ MBEDTLS_ECP_DP_SECP521R1, /*!< Domain parameters for 521-bit NIST curve. */
+ MBEDTLS_ECP_DP_BP256R1, /*!< Domain parameters for 256-bit Brainpool curve. */
+ MBEDTLS_ECP_DP_BP384R1, /*!< Domain parameters for 384-bit Brainpool curve. */
+ MBEDTLS_ECP_DP_BP512R1, /*!< Domain parameters for 512-bit Brainpool curve. */
+ MBEDTLS_ECP_DP_CURVE25519, /*!< Domain parameters for a Curve25519 curve. */
+ MBEDTLS_ECP_DP_CURVE448, /*!< Domain parameters for a Curve448 curve. */
+ MBEDTLS_ECP_DP_SECP192K1, /*!< Domain parameters for 192-bit "Koblitz" curve. */
+ MBEDTLS_ECP_DP_SECP224K1, /*!< Domain parameters for 224-bit "Koblitz" curve. */
+ MBEDTLS_ECP_DP_SECP256K1, /*!< Domain parameters for 256-bit "Koblitz" curve. */
} mbedtls_ecp_group_id;
/**
- * Number of supported curves (plus one for NONE).
+ * The number of supported curves, plus one for none.
*
- * (Montgomery curves excluded for now.)
+ * \note Montgomery curves are currently excluded.
*/
#define MBEDTLS_ECP_DP_MAX 12
/**
- * Curve information for use by other modules
+ * Curve information, for use by other modules.
*/
typedef struct
{
- mbedtls_ecp_group_id grp_id; /*!< Internal identifier */
- uint16_t tls_id; /*!< TLS NamedCurve identifier */
- uint16_t bit_size; /*!< Curve size in bits */
- const char *name; /*!< Human-friendly name */
+ mbedtls_ecp_group_id grp_id; /*!< An internal identifier. */
+ uint16_t tls_id; /*!< The TLS NamedCurve identifier. */
+ uint16_t bit_size; /*!< The size of the curve in bits. */
+ const char *name; /*!< A human-friendly name. */
} mbedtls_ecp_curve_info;
/**
- * \brief ECP point structure (jacobian coordinates)
+ * \brief The ECP point structure, in jacobian coordinates.
*
* \note All functions expect and return points satisfying
- * the following condition: Z == 0 or Z == 1. (Other
- * values of Z are used by internal functions only.)
+ * the following condition: \p Z == 0 or \p Z == 1. Other
+ * values of \p Z are used only by internal functions.
* The point is zero, or "at infinity", if Z == 0.
* Otherwise, X and Y are its standard (affine) coordinates.
*/
typedef struct
{
- mbedtls_mpi X; /*!< the point's X coordinate */
- mbedtls_mpi Y; /*!< the point's Y coordinate */
- mbedtls_mpi Z; /*!< the point's Z coordinate */
+ mbedtls_mpi X; /*!< The X coordinate of the ECP point. */
+ mbedtls_mpi Y; /*!< The Y coordinate of the ECP point. */
+ mbedtls_mpi Z; /*!< The Z coordinate of the ECP point. */
}
mbedtls_ecp_point;
/**
- * \brief ECP group structure
+ * \brief The ECP group structure.
*
- * We consider two types of curves equations:
- * 1. Short Weierstrass y^2 = x^3 + A x + B mod P (SEC1 + RFC 4492)
- * 2. Montgomery, y^2 = x^3 + A x^2 + x mod P (Curve25519 + draft)
- * In both cases, a generator G for a prime-order subgroup is fixed. In the
- * short weierstrass, this subgroup is actually the whole curve, and its
- * cardinal is denoted by N.
+ * We consider two types of curve equations:
+ * <ul><li>Short Weierstrass: y^2 = x^3 + \p A x + \p B mod P
+ * (SEC1 + RFC-4492)</li>
+ * <li>Montgomery: y^2 = x^3 + A x^2 + x mod P (Curve25519 + draft)</li></ul>
+ * In both cases, the generator (G) for a prime-order subgroup is fixed.
*
- * In the case of Short Weierstrass curves, our code requires that N is an odd
- * prime. (Use odd in mbedtls_ecp_mul() and prime in mbedtls_ecdsa_sign() for blinding.)
+ * For Short Weierstrass, this subgroup is the whole curve, and its
+ * cardinal is denoted by \p N. Our code requires that \p N is an odd prime.
*
- * In the case of Montgomery curves, we don't store A but (A + 2) / 4 which is
- * the quantity actually used in the formulas. Also, nbits is not the size of N
- * but the required size for private keys.
+ * \note For blinding, use odd in mbedtls_ecp_mul() and prime in
+ * mbedtls_ecdsa_sign().
*
- * If modp is NULL, reduction modulo P is done using a generic algorithm.
- * Otherwise, it must point to a function that takes an mbedtls_mpi in the range
- * 0..2^(2*pbits)-1 and transforms it in-place in an integer of little more
- * than pbits, so that the integer may be efficiently brought in the 0..P-1
- * range by a few additions or substractions. It must return 0 on success and
- * non-zero on failure.
+ * For Montgomery curves, we do not store \p A, but (A + 2) / 4, which is
+ * the quantity used in the formulas. Additionally, \p nbits is not the
+ * size of \p N but the required size for private keys.
+ *
+ * If \p modp is NULL, reduction modulo \p P is done using a generic algorithm.
+ * Otherwise, it must point to a function that takes an \p mbedtls_mpi in the
+ * range of 0..2^(2*pbits)-1, and transforms it in-place in an integer of
+ * little more than \p pbits, so that the integer may be efficiently brought
+ * in the 0..P-1 range by a few additions or substractions.
+ *
+ * \return \c 0 on success
+ * \return Non-zero on failure.
*/
typedef struct
{
- mbedtls_ecp_group_id id; /*!< internal group identifier */
- mbedtls_mpi P; /*!< prime modulus of the base field */
- mbedtls_mpi A; /*!< 1. A in the equation, or 2. (A + 2) / 4 */
- mbedtls_mpi B; /*!< 1. B in the equation, or 2. unused */
- mbedtls_ecp_point G; /*!< generator of the (sub)group used */
- mbedtls_mpi N; /*!< the order of G */
- size_t pbits; /*!< number of bits in P */
- size_t nbits; /*!< number of bits in 1. P, or 2. private keys */
- unsigned int h; /*!< internal: 1 if the constants are static */
- int (*modp)(mbedtls_mpi *); /*!< function for fast reduction mod P */
- int (*t_pre)(mbedtls_ecp_point *, void *); /*!< unused */
- int (*t_post)(mbedtls_ecp_point *, void *); /*!< unused */
- void *t_data; /*!< unused */
- mbedtls_ecp_point *T; /*!< pre-computed points for ecp_mul_comb() */
- size_t T_size; /*!< number for pre-computed points */
+ mbedtls_ecp_group_id id; /*!< An internal group identifier. */
+ mbedtls_mpi P; /*!< A prime modulus of the base field. */
+ mbedtls_mpi A; /*!< \p A in the equation or <code>(A + 2) / 4</code>. */
+ mbedtls_mpi B; /*!< \p B in the equation or unused. */
+ mbedtls_ecp_point G; /*!< The generator of the (sub)group used. */
+ mbedtls_mpi N; /*!< The order of \p G. */
+ size_t pbits; /*!< The number of bits in \p P.*/
+ size_t nbits; /*!< The number of bits in \p P, or the private
+ keys. */
+ unsigned int h; /*!< \internal 1 if the constants are static. */
+ int (*modp)(mbedtls_mpi *); /*!< The function for fast reduction mod P.*/
+ int (*t_pre)(mbedtls_ecp_point *, void *); /*!< Unused. */
+ int (*t_post)(mbedtls_ecp_point *, void *); /*!< Unused. */
+ void *t_data; /*!< Unused. */
+ mbedtls_ecp_point *T; /*!< Pre-computed points for ecp_mul_comb(). */
+ size_t T_size; /*!< The number for pre-computed points. */
}
mbedtls_ecp_group;
/**
- * \brief ECP key pair structure
+ * \brief The ECP key-pair structure.
*
- * A generic key pair that could be used for ECDSA, fixed ECDH, etc.
+ * A generic key-pair that may be used for ECDSA and fixed ECDH, for example.
*
- * \note Members purposefully in the same order as struc mbedtls_ecdsa_context.
+ * \note Members are deliberately in the same order as in the
+ * #mbedtls_ecdsa_context structure.
*/
typedef struct
{
- mbedtls_ecp_group grp; /*!< Elliptic curve and base point */
- mbedtls_mpi d; /*!< our secret value */
- mbedtls_ecp_point Q; /*!< our public value */
+ mbedtls_ecp_group grp; /*!< The elliptic curve and base point. */
+ mbedtls_mpi d; /*!< Our secret value. */
+ mbedtls_ecp_point Q; /*!< Our public value. */
}
mbedtls_ecp_keypair;
@@ -177,15 +194,15 @@
* \name SECTION: Module settings
*
* The configuration options you can set for this module are in this section.
- * Either change them in config.h or define them on the compiler command line.
+ * Either change them in config.h, or define them using the compiler command line.
* \{
*/
#if !defined(MBEDTLS_ECP_MAX_BITS)
/**
- * Maximum size of the groups (that is, of N and P)
+ * The maximum size of the groups, that is, of N and P.
*/
-#define MBEDTLS_ECP_MAX_BITS 521 /**< Maximum bit size of groups */
+#define MBEDTLS_ECP_MAX_BITS 521 /**< The maximum size of groups, in bits. */
#endif
#define MBEDTLS_ECP_MAX_BYTES ( ( MBEDTLS_ECP_MAX_BITS + 7 ) / 8 )
@@ -212,7 +229,7 @@
* 224 475 475 453 398 342
* 192 640 640 633 587 476
*/
-#define MBEDTLS_ECP_WINDOW_SIZE 6 /**< Maximum window size used */
+#define MBEDTLS_ECP_WINDOW_SIZE 6 /**< The maximum window size used. */
#endif /* MBEDTLS_ECP_WINDOW_SIZE */
#if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM)
@@ -227,7 +244,7 @@
*
* Change this value to 0 to reduce peak memory usage.
*/
-#define MBEDTLS_ECP_FIXED_POINT_OPTIM 1 /**< Enable fixed-point speed-up */
+#define MBEDTLS_ECP_FIXED_POINT_OPTIM 1 /**< Enable fixed-point speed-up. */
#endif /* MBEDTLS_ECP_FIXED_POINT_OPTIM */
/* \} name SECTION: Module settings */
@@ -235,25 +252,26 @@
/*
* Point formats, from RFC 4492's enum ECPointFormat
*/
-#define MBEDTLS_ECP_PF_UNCOMPRESSED 0 /**< Uncompressed point format */
-#define MBEDTLS_ECP_PF_COMPRESSED 1 /**< Compressed point format */
+#define MBEDTLS_ECP_PF_UNCOMPRESSED 0 /**< Uncompressed point format. */
+#define MBEDTLS_ECP_PF_COMPRESSED 1 /**< Compressed point format. */
/*
* Some other constants from RFC 4492
*/
-#define MBEDTLS_ECP_TLS_NAMED_CURVE 3 /**< ECCurveType's named_curve */
+#define MBEDTLS_ECP_TLS_NAMED_CURVE 3 /**< The named_curve of ECCurveType. */
/**
- * \brief Get the list of supported curves in order of preferrence
- * (full information)
+ * \brief This function retrieves the information defined in
+ * mbedtls_ecp_curve_info()for all supported curves in order
+ * of preference.
*
- * \return A statically allocated array, the last entry is 0.
+ * \return A statically allocated array. The last entry is 0.
*/
const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list( void );
/**
- * \brief Get the list of supported curves in order of preferrence
- * (grp_id only)
+ * \brief This function retrieves the grp_id of all supported curves
+ * in order of preference.
*
* \return A statically allocated array,
* terminated with MBEDTLS_ECP_DP_NONE.
@@ -261,358 +279,390 @@
const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list( void );
/**
- * \brief Get curve information from an internal group identifier
+ * \brief This function retrieves curve information from an internal
+ * group identifier.
*
- * \param grp_id A MBEDTLS_ECP_DP_XXX value
+ * \param grp_id An \c MBEDTLS_ECP_DP_XXX value.
*
- * \return The associated curve information or NULL
+ * \return The associated curve information, or NULL.
*/
const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id( mbedtls_ecp_group_id grp_id );
/**
- * \brief Get curve information from a TLS NamedCurve value
+ * \brief This function retrieves curve information from a TLS
+ * NamedCurve value.
*
- * \param tls_id A MBEDTLS_ECP_DP_XXX value
+ * \param tls_id An \c MBEDTLS_ECP_DP_XXX value.
*
- * \return The associated curve information or NULL
+ * \return The associated curve information, or NULL.
*/
const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id( uint16_t tls_id );
/**
- * \brief Get curve information from a human-readable name
+ * \brief This function retrieves curve information from a
+ * human-readable name.
*
- * \param name The name
+ * \param name The human-readable name.
*
- * \return The associated curve information or NULL
+ * \return The associated curve information, or NULL.
*/
const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name( const char *name );
/**
- * \brief Initialize a point (as zero)
+ * \brief This function initializes a point as zero.
+ *
+ * \param pt The point to initialize.
*/
void mbedtls_ecp_point_init( mbedtls_ecp_point *pt );
/**
- * \brief Initialize a group (to something meaningless)
+ * \brief This function initializes a group to something meaningless.
*/
void mbedtls_ecp_group_init( mbedtls_ecp_group *grp );
/**
- * \brief Initialize a key pair (as an invalid one)
+ * \brief This function initializes a key pair as an invalid one.
+ *
+ * \param key The key pair to initialize.
*/
void mbedtls_ecp_keypair_init( mbedtls_ecp_keypair *key );
/**
- * \brief Free the components of a point
+ * \brief This function frees the components of a point.
+ *
+ * \param pt The point to free.
*/
void mbedtls_ecp_point_free( mbedtls_ecp_point *pt );
/**
- * \brief Free the components of an ECP group
+ * \brief This function frees the components of an ECP group.
+ * \param grp The group to free.
*/
void mbedtls_ecp_group_free( mbedtls_ecp_group *grp );
/**
- * \brief Free the components of a key pair
+ * \brief This function frees the components of a key pair.
+ * \param key The key pair to free.
*/
void mbedtls_ecp_keypair_free( mbedtls_ecp_keypair *key );
/**
- * \brief Copy the contents of point Q into P
+ * \brief This function copies the contents of point \p Q into
+ * point \p P.
*
- * \param P Destination point
- * \param Q Source point
+ * \param P The destination point.
+ * \param Q The source point.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation fails.
*/
int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q );
/**
- * \brief Copy the contents of a group object
+ * \brief This function copies the contents of group \p src into
+ * group \p dst.
*
- * \param dst Destination group
- * \param src Source group
+ * \param dst The destination group.
+ * \param src The source group.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation fails.
*/
int mbedtls_ecp_group_copy( mbedtls_ecp_group *dst, const mbedtls_ecp_group *src );
/**
- * \brief Set a point to zero
+ * \brief This function sets a point to zero.
*
- * \param pt Destination point
+ * \param pt The point to set.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation fails.
*/
int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt );
/**
- * \brief Tell if a point is zero
+ * \brief This function checks if a point is zero.
*
- * \param pt Point to test
+ * \param pt The point to test.
*
- * \return 1 if point is zero, 0 otherwise
+ * \return \c 1 if point is zero.
+ * \return \c 0 if point is non-zero.
*/
int mbedtls_ecp_is_zero( mbedtls_ecp_point *pt );
/**
- * \brief Compare two points
+ * \brief This function compares two points.
*
- * \note This assumes the points are normalized. Otherwise,
+ * \note This assumes that the points are normalized. Otherwise,
* they may compare as "not equal" even if they are.
*
- * \param P First point to compare
- * \param Q Second point to compare
+ * \param P The first point to compare.
+ * \param Q The second point to compare.
*
- * \return 0 if the points are equal,
- * MBEDTLS_ERR_ECP_BAD_INPUT_DATA otherwise
+ * \return \c 0 if the points are equal.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if the points are not equal.
*/
int mbedtls_ecp_point_cmp( const mbedtls_ecp_point *P,
const mbedtls_ecp_point *Q );
/**
- * \brief Import a non-zero point from two ASCII strings
+ * \brief This function imports a non-zero point from two ASCII
+ * strings.
*
- * \param P Destination point
- * \param radix Input numeric base
- * \param x First affine coordinate as a null-terminated string
- * \param y Second affine coordinate as a null-terminated string
+ * \param P The destination point.
+ * \param radix The numeric base of the input.
+ * \param x The first affine coordinate, as a null-terminated string.
+ * \param y The second affine coordinate, as a null-terminated string.
*
- * \return 0 if successful, or a MBEDTLS_ERR_MPI_XXX error code
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_MPI_XXX error code on failure.
*/
int mbedtls_ecp_point_read_string( mbedtls_ecp_point *P, int radix,
const char *x, const char *y );
/**
- * \brief Export a point into unsigned binary data
+ * \brief This function exports a point into unsigned binary data.
*
- * \param grp Group to which the point should belong
- * \param P Point to export
- * \param format Point format, should be a MBEDTLS_ECP_PF_XXX macro
- * \param olen Length of the actual output
- * \param buf Output buffer
- * \param buflen Length of the output buffer
+ * \param grp The group to which the point should belong.
+ * \param P The point to export.
+ * \param format The point format. Should be an \c MBEDTLS_ECP_PF_XXX macro.
+ * \param olen The length of the output.
+ * \param buf The output buffer.
+ * \param buflen The length of the output buffer.
*
- * \return 0 if successful,
- * or MBEDTLS_ERR_ECP_BAD_INPUT_DATA
- * or MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA
+ * or #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL on failure.
*/
int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *P,
int format, size_t *olen,
unsigned char *buf, size_t buflen );
/**
- * \brief Import a point from unsigned binary data
+ * \brief This function imports a point from unsigned binary data.
*
- * \param grp Group to which the point should belong
- * \param P Point to import
- * \param buf Input buffer
- * \param ilen Actual length of input
+ * \note This function does not check that the point actually
+ * belongs to the given group, see mbedtls_ecp_check_pubkey()
+ * for that.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed,
- * MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the point format
+ * \param grp The group to which the point should belong.
+ * \param P The point to import.
+ * \param buf The input buffer.
+ * \param ilen The length of the input.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed.
+ * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the point format
* is not implemented.
*
- * \note This function does NOT check that the point actually
- * belongs to the given group, see mbedtls_ecp_check_pubkey() for
- * that.
*/
int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp, mbedtls_ecp_point *P,
const unsigned char *buf, size_t ilen );
/**
- * \brief Import a point from a TLS ECPoint record
+ * \brief This function imports a point from a TLS ECPoint record.
*
- * \param grp ECP group used
- * \param pt Destination point
- * \param buf $(Start of input buffer)
- * \param len Buffer length
+ * \note On function return, \p buf is updated to point to immediately
+ * after the ECPoint.
*
- * \note buf is updated to point right after the ECPoint on exit
+ * \param grp The ECP group used.
+ * \param pt The destination point.
+ * \param buf The address of the pointer to the start of input buffer.
+ * \param len The length of the buffer.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_XXX if initialization failed
- * MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_MPI_XXX error code if initialization failed.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid.
*/
int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp, mbedtls_ecp_point *pt,
const unsigned char **buf, size_t len );
/**
- * \brief Export a point as a TLS ECPoint record
+ * \brief This function exports a point as a TLS ECPoint record.
*
- * \param grp ECP group used
- * \param pt Point to export
- * \param format Export format
- * \param olen length of data written
- * \param buf Buffer to write to
- * \param blen Buffer length
+ * \param grp The ECP group used.
+ * \param pt The point to export.
+ * \param format The export format.
+ * \param olen The length of data written.
+ * \param buf The Buffer to write to.
+ * \param blen The length of the Buffer.
*
- * \return 0 if successful,
- * or MBEDTLS_ERR_ECP_BAD_INPUT_DATA
- * or MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA or
+ * #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL on failure.
*/
int mbedtls_ecp_tls_write_point( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt,
int format, size_t *olen,
unsigned char *buf, size_t blen );
/**
- * \brief Set a group using well-known domain parameters
+ * \brief This function sets a group using well-known domain parameters.
*
- * \param grp Destination group
- * \param id Index in the list of well-known domain parameters
+ * \note The index should be a value of the NamedCurve enum,
+ * as defined in <em>RFC-4492: Elliptic Curve Cryptography
+ * (ECC) Cipher Suites for Transport Layer Security (TLS)</em>,
+ * usually in the form of an \c MBEDTLS_ECP_DP_XXX macro.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_XXX if initialization failed
- * MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE for unkownn groups
+ * \param grp The destination group.
+ * \param id The index in the list of well-known domain parameters.
*
- * \note Index should be a value of RFC 4492's enum NamedCurve,
- * usually in the form of a MBEDTLS_ECP_DP_XXX macro.
+ * \return \c 0 on success,
+ * \return An \c MBEDTLS_ERR_MPI_XXX error code if initialization fails.
+ * \return #MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE for unkownn groups.
+
*/
int mbedtls_ecp_group_load( mbedtls_ecp_group *grp, mbedtls_ecp_group_id id );
/**
- * \brief Set a group from a TLS ECParameters record
+ * \brief This function sets a group from a TLS ECParameters record.
*
- * \param grp Destination group
- * \param buf &(Start of input buffer)
- * \param len Buffer length
+ * \note \p buf is updated to point right after ECParameters on exit.
*
- * \note buf is updated to point right after ECParameters on exit
+ * \param grp The destination group.
+ * \param buf The address of the pointer to the start of input buffer.
+ * \param len The length of the buffer.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_MPI_XXX if initialization failed
- * MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_MPI_XXX error code if initialization fails.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if input is invalid.
*/
int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp, const unsigned char **buf, size_t len );
/**
- * \brief Write the TLS ECParameters record for a group
+ * \brief This function writes the TLS ECParameters record for a group.
*
- * \param grp ECP group used
- * \param olen Number of bytes actually written
- * \param buf Buffer to write to
- * \param blen Buffer length
+ * \param grp The ECP group used.
+ * \param olen The number of Bytes written.
+ * \param buf The buffer to write to.
+ * \param blen The length of the buffer.
*
- * \return 0 if successful,
- * or MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL on failure.
*/
int mbedtls_ecp_tls_write_group( const mbedtls_ecp_group *grp, size_t *olen,
unsigned char *buf, size_t blen );
/**
- * \brief Multiplication by an integer: R = m * P
- * (Not thread-safe to use same group in multiple threads)
+ * \brief This function performs multiplication of a point by
+ * an integer: \p R = \p m * \p P.
*
- * \note In order to prevent timing attacks, this function
- * executes the exact same sequence of (base field)
- * operations for any valid m. It avoids any if-branch or
- * array index depending on the value of m.
+ * It is not thread-safe to use same group in multiple threads.
*
- * \note If f_rng is not NULL, it is used to randomize intermediate
- * results in order to prevent potential timing attacks
- * targeting these results. It is recommended to always
- * provide a non-NULL f_rng (the overhead is negligible).
+ * \note To prevent timing attacks, this function
+ * executes the exact same sequence of base-field
+ * operations for any valid \p m. It avoids any if-branch or
+ * array index depending on the value of \p m.
*
- * \param grp ECP group
- * \param R Destination point
- * \param m Integer by which to multiply
- * \param P Point to multiply
- * \param f_rng RNG function (see notes)
- * \param p_rng RNG parameter
+ * \note If \p f_rng is not NULL, it is used to randomize
+ * intermediate results to prevent potential timing attacks
+ * targeting these results. We recommend always providing
+ * a non-NULL \p f_rng. The overhead is negligible.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_ECP_INVALID_KEY if m is not a valid privkey
- * or P is not a valid pubkey,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ * \param grp The ECP group.
+ * \param R The destination point.
+ * \param m The integer by which to multiply.
+ * \param P The point to multiply.
+ * \param f_rng The RNG function.
+ * \param p_rng The RNG context.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m is not a valid privkey,
+ * or \p P is not a valid pubkey.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure.
*/
int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
- * \brief Multiplication and addition of two points by integers:
- * R = m * P + n * Q
- * (Not thread-safe to use same group in multiple threads)
+ * \brief This function performs multiplication and addition of two
+ * points by integers: \p R = \p m * \p P + \p n * \p Q
+
+ * It is not thread-safe to use same group in multiple threads.
*
- * \note In contrast to mbedtls_ecp_mul(), this function does not guarantee
- * a constant execution flow and timing.
+ * \note In contrast to mbedtls_ecp_mul(), this function does not
+ * guarantee a constant execution flow and timing.
*
- * \param grp ECP group
- * \param R Destination point
- * \param m Integer by which to multiply P
- * \param P Point to multiply by m
- * \param n Integer by which to multiply Q
- * \param Q Point to be multiplied by n
+ * \param grp The ECP group.
+ * \param R The destination point.
+ * \param m The integer by which to multiply \p P.
+ * \param P The point to multiply by \p m.
+ * \param n The integer by which to multiply \p Q.
+ * \param Q The point to be multiplied by \p n.
*
- * \return 0 if successful,
- * MBEDTLS_ERR_ECP_INVALID_KEY if m or n is not a valid privkey
- * or P or Q is not a valid pubkey,
- * MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_ECP_INVALID_KEY if \p m or \p n are not
+ * valid private keys, or \p P or \p Q are not valid public
+ * keys.
+ * \return #MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure.
*/
int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
const mbedtls_mpi *n, const mbedtls_ecp_point *Q );
/**
- * \brief Check that a point is a valid public key on this curve
+ * \brief This function checks that a point is a valid public key
+ * on this curve.
*
- * \param grp Curve/group the point should belong to
- * \param pt Point to check
+ * It only checks that the point is non-zero, has
+ * valid coordinates and lies on the curve. It does not verify
+ * that it is indeed a multiple of \p G. This additional
+ * check is computationally more expensive, is not required
+ * by standards, and should not be necessary if the group
+ * used has a small cofactor. In particular, it is useless for
+ * the NIST groups which all have a cofactor of 1.
*
- * \return 0 if point is a valid public key,
- * MBEDTLS_ERR_ECP_INVALID_KEY otherwise.
+ * \note This function uses bare components rather than an
+ * mbedtls_ecp_keypair() structure, to ease use with other
+ * structures. For example, mbedtls_ecdh_context() or
+ * mbedtls_ecdsa_context().
*
- * \note This function only checks the point is non-zero, has valid
- * coordinates and lies on the curve, but not that it is
- * indeed a multiple of G. This is additional check is more
- * expensive, isn't required by standards, and shouldn't be
- * necessary if the group used has a small cofactor. In
- * particular, it is useless for the NIST groups which all
- * have a cofactor of 1.
+ * \param grp The curve or group the point should belong to.
+ * \param pt The point to check.
*
- * \note Uses bare components rather than an mbedtls_ecp_keypair structure
- * in order to ease use with other structures such as
- * mbedtls_ecdh_context of mbedtls_ecdsa_context.
+ * \return \c 0 if the point is a valid public key.
+ * \return #MBEDTLS_ERR_ECP_INVALID_KEY otherwise.
*/
int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *pt );
/**
- * \brief Check that an mbedtls_mpi is a valid private key for this curve
+ * \brief This function checks that an \p mbedtls_mpi is a valid private
+ * key for this curve.
*
- * \param grp Group used
- * \param d Integer to check
+ * \note This function uses bare components rather than an
+ * mbedtls_ecp_keypair() structure to ease use with other
+ * structures such as mbedtls_ecdh_context() or
+ * mbedtls_ecdsa_context().
*
- * \return 0 if point is a valid private key,
- * MBEDTLS_ERR_ECP_INVALID_KEY otherwise.
+ * \param grp The group used.
+ * \param d The integer to check.
*
- * \note Uses bare components rather than an mbedtls_ecp_keypair structure
- * in order to ease use with other structures such as
- * mbedtls_ecdh_context of mbedtls_ecdsa_context.
+ * \return \c 0 if the point is a valid private key.
+ * \return #MBEDTLS_ERR_ECP_INVALID_KEY otherwise.
*/
int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *d );
/**
- * \brief Generate a keypair with configurable base point
+ * \brief This function generates a keypair with a configurable base
+ * point.
*
- * \param grp ECP group
- * \param G Chosen base point
- * \param d Destination MPI (secret part)
- * \param Q Destination point (public part)
- * \param f_rng RNG function
- * \param p_rng RNG parameter
+ * \note This function uses bare components rather than an
+ * mbedtls_ecp_keypair() structure to ease use with other
+ * structures such as mbedtls_ecdh_context() or
+ * mbedtls_ecdsa_context().
+*
+ * \param grp The ECP group.
+ * \param G The chosen base point.
+ * \param d The destination MPI (secret part).
+ * \param Q The destination point (public part).
+ * \param f_rng The RNG function.
+ * \param p_rng The RNG context.
*
- * \return 0 if successful,
- * or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
- *
- * \note Uses bare components rather than an mbedtls_ecp_keypair structure
- * in order to ease use with other structures such as
- * mbedtls_ecdh_context of mbedtls_ecdsa_context.
- */
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code
+ * on failure.
+ */
int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
const mbedtls_ecp_point *G,
mbedtls_mpi *d, mbedtls_ecp_point *Q,
@@ -620,57 +670,64 @@
void *p_rng );
/**
- * \brief Generate a keypair
+ * \brief This function generates a keypair.
*
- * \param grp ECP group
- * \param d Destination MPI (secret part)
- * \param Q Destination point (public part)
- * \param f_rng RNG function
- * \param p_rng RNG parameter
+ * \note This function uses bare components rather than an
+ * mbedtls_ecp_keypair() structure to ease use with other
+ * structures such as mbedtls_ecdh_context() or
+ * mbedtls_ecdsa_context().
*
- * \return 0 if successful,
- * or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
+ * \param grp The ECP group.
+ * \param d The destination MPI (secret part).
+ * \param Q The destination point (public part).
+ * \param f_rng The RNG function.
+ * \param p_rng The RNG context.
*
- * \note Uses bare components rather than an mbedtls_ecp_keypair structure
- * in order to ease use with other structures such as
- * mbedtls_ecdh_context of mbedtls_ecdsa_context.
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code
+ * on failure.
*/
int mbedtls_ecp_gen_keypair( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng );
/**
- * \brief Generate a keypair
+ * \brief This function generates a key.
*
- * \param grp_id ECP group identifier
- * \param key Destination keypair
- * \param f_rng RNG function
- * \param p_rng RNG parameter
+ * \param grp_id The ECP group identifier.
+ * \param key The destination key.
+ * \param f_rng The RNG function.
+ * \param p_rng The RNG context.
*
- * \return 0 if successful,
- * or a MBEDTLS_ERR_ECP_XXX or MBEDTLS_MPI_XXX error code
+ * \return \c 0 on success.
+ * \return An \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_MPI_XXX error code
+ * on failure.
*/
int mbedtls_ecp_gen_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
- * \brief Check a public-private key pair
+ * \brief This function checks a public-private key pair.
*
- * \param pub Keypair structure holding a public key
- * \param prv Keypair structure holding a private (plus public) key
+ * \param pub The keypair structure holding the public key.
+ * \param prv The keypair structure holding the private key.
*
- * \return 0 if successful (keys are valid and match), or
- * MBEDTLS_ERR_ECP_BAD_INPUT_DATA, or
- * a MBEDTLS_ERR_ECP_XXX or MBEDTLS_ERR_MPI_XXX code.
+ * \note The both are keypairs, and may optionally hold the corresponding other key, but the public key passed in thee pub is checked against the private key passed in prv.
+ *
+ * \return \c 0 on success - the keys are valid and match.
+ * \return #MBEDTLS_ERR_ECP_BAD_INPUT_DATA, or an \c
+ * MBEDTLS_ERR_ECP_XXX or an \c MBEDTLS_ERR_MPI_XXX
+ * error code on failure.
*/
int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv );
#if defined(MBEDTLS_SELF_TEST)
/**
- * \brief Checkup routine
+ * \brief The ECP checkup routine.
*
- * \return 0 if successful, or 1 if a test failed
+ * \return \c 0 on success.
+ * \return \c 1 on failure.
*/
int mbedtls_ecp_self_test( int verbose );