pk.h

00001 /**
00002  * \file pk.h
00003  *
00004  * \brief Public Key abstraction layer
00005  *
00006  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00007  *  SPDX-License-Identifier: Apache-2.0
00008  *
00009  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00010  *  not use this file except in compliance with the License.
00011  *  You may obtain a copy of the License at
00012  *
00013  *  http://www.apache.org/licenses/LICENSE-2.0
00014  *
00015  *  Unless required by applicable law or agreed to in writing, software
00016  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00017  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00018  *  See the License for the specific language governing permissions and
00019  *  limitations under the License.
00020  *
00021  *  This file is part of mbed TLS (https://tls.mbed.org)
00022  */
00023 
00024 #ifndef MBEDTLS_PK_H
00025 #define MBEDTLS_PK_H
00026 
00027 #if !defined(MBEDTLS_CONFIG_FILE)
00028 #include "config.h"
00029 #else
00030 #include MBEDTLS_CONFIG_FILE
00031 #endif
00032 
00033 #include "md.h"
00034 
00035 #if defined(MBEDTLS_RSA_C)
00036 #include "rsa.h"
00037 #endif
00038 
00039 #if defined(MBEDTLS_ECP_C)
00040 #include "ecp.h"
00041 #endif
00042 
00043 #if defined(MBEDTLS_ECDSA_C)
00044 #include "ecdsa.h"
00045 #endif
00046 
00047 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
00048     !defined(inline) && !defined(__cplusplus)
00049 #define inline __inline
00050 #endif
00051 
00052 #define MBEDTLS_ERR_PK_ALLOC_FAILED        -0x3F80  /**< Memory allocation failed. */
00053 #define MBEDTLS_ERR_PK_TYPE_MISMATCH       -0x3F00  /**< Type mismatch, eg attempt to encrypt with an ECDSA key */
00054 #define MBEDTLS_ERR_PK_BAD_INPUT_DATA      -0x3E80  /**< Bad input parameters to function. */
00055 #define MBEDTLS_ERR_PK_FILE_IO_ERROR       -0x3E00  /**< Read/write of file failed. */
00056 #define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80  /**< Unsupported key version */
00057 #define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT  -0x3D00  /**< Invalid key tag or value. */
00058 #define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG      -0x3C80  /**< Key algorithm is unsupported (only RSA and EC are supported). */
00059 #define MBEDTLS_ERR_PK_PASSWORD_REQUIRED   -0x3C00  /**< Private key password can't be empty. */
00060 #define MBEDTLS_ERR_PK_PASSWORD_MISMATCH   -0x3B80  /**< Given private key password does not allow for correct decryption. */
00061 #define MBEDTLS_ERR_PK_INVALID_PUBKEY      -0x3B00  /**< The pubkey tag or value is invalid (only RSA and EC are supported). */
00062 #define MBEDTLS_ERR_PK_INVALID_ALG         -0x3A80  /**< The algorithm tag or value is invalid. */
00063 #define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00  /**< Elliptic curve is unsupported (only NIST curves are supported). */
00064 #define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980  /**< Unavailable feature, e.g. RSA disabled for RSA key. */
00065 #define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900  /**< The signature is valid but its length is less than expected. */
00066 
00067 #ifdef __cplusplus
00068 extern "C" {
00069 #endif
00070 
00071 /**
00072  * \brief          Public key types
00073  */
00074 typedef enum {
00075     MBEDTLS_PK_NONE=0,
00076     MBEDTLS_PK_RSA,
00077     MBEDTLS_PK_ECKEY,
00078     MBEDTLS_PK_ECKEY_DH,
00079     MBEDTLS_PK_ECDSA,
00080     MBEDTLS_PK_RSA_ALT,
00081     MBEDTLS_PK_RSASSA_PSS,
00082 } mbedtls_pk_type_t;
00083 
00084 /**
00085  * \brief           Options for RSASSA-PSS signature verification.
00086  *                  See \c mbedtls_rsa_rsassa_pss_verify_ext()
00087  */
00088 typedef struct
00089 {
00090     mbedtls_md_type_t mgf1_hash_id;
00091     int expected_salt_len;
00092 
00093 } mbedtls_pk_rsassa_pss_options;
00094 
00095 /**
00096  * \brief           Types for interfacing with the debug module
00097  */
00098 typedef enum
00099 {
00100     MBEDTLS_PK_DEBUG_NONE = 0,
00101     MBEDTLS_PK_DEBUG_MPI,
00102     MBEDTLS_PK_DEBUG_ECP,
00103 } mbedtls_pk_debug_type;
00104 
00105 /**
00106  * \brief           Item to send to the debug module
00107  */
00108 typedef struct
00109 {
00110     mbedtls_pk_debug_type type;
00111     const char *name;
00112     void *value;
00113 } mbedtls_pk_debug_item;
00114 
00115 /** Maximum number of item send for debugging, plus 1 */
00116 #define MBEDTLS_PK_DEBUG_MAX_ITEMS 3
00117 
00118 /**
00119  * \brief           Public key information and operations
00120  */
00121 typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
00122 
00123 /**
00124  * \brief           Public key container
00125  */
00126 typedef struct
00127 {
00128     const mbedtls_pk_info_t *   pk_info; /**< Public key informations        */
00129     void *                      pk_ctx;  /**< Underlying public key context  */
00130 } mbedtls_pk_context;
00131 
00132 #if defined(MBEDTLS_RSA_C)
00133 /**
00134  * Quick access to an RSA context inside a PK context.
00135  *
00136  * \warning You must make sure the PK context actually holds an RSA context
00137  * before using this function!
00138  */
00139 static inline mbedtls_rsa_context *mbedtls_pk_rsa( const mbedtls_pk_context pk )
00140 {
00141     return( (mbedtls_rsa_context *) (pk).pk_ctx );
00142 }
00143 #endif /* MBEDTLS_RSA_C */
00144 
00145 #if defined(MBEDTLS_ECP_C)
00146 /**
00147  * Quick access to an EC context inside a PK context.
00148  *
00149  * \warning You must make sure the PK context actually holds an EC context
00150  * before using this function!
00151  */
00152 static inline mbedtls_ecp_keypair *mbedtls_pk_ec( const mbedtls_pk_context pk )
00153 {
00154     return( (mbedtls_ecp_keypair *) (pk).pk_ctx );
00155 }
00156 #endif /* MBEDTLS_ECP_C */
00157 
00158 #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
00159 /**
00160  * \brief           Types for RSA-alt abstraction
00161  */
00162 typedef int (*mbedtls_pk_rsa_alt_decrypt_func)( void *ctx, int mode, size_t *olen,
00163                     const unsigned char *input, unsigned char *output,
00164                     size_t output_max_len );
00165 typedef int (*mbedtls_pk_rsa_alt_sign_func)( void *ctx,
00166                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
00167                     int mode, mbedtls_md_type_t md_alg, unsigned int hashlen,
00168                     const unsigned char *hash, unsigned char *sig );
00169 typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)( void *ctx );
00170 #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
00171 
00172 /**
00173  * \brief           Return information associated with the given PK type
00174  *
00175  * \param pk_type   PK type to search for.
00176  *
00177  * \return          The PK info associated with the type or NULL if not found.
00178  */
00179 const mbedtls_pk_info_t *mbedtls_pk_info_from_type( mbedtls_pk_type_t pk_type );
00180 
00181 /**
00182  * \brief           Initialize a mbedtls_pk_context (as NONE)
00183  */
00184 void mbedtls_pk_init( mbedtls_pk_context *ctx );
00185 
00186 /**
00187  * \brief           Free a mbedtls_pk_context
00188  */
00189 void mbedtls_pk_free( mbedtls_pk_context *ctx );
00190 
00191 /**
00192  * \brief           Initialize a PK context with the information given
00193  *                  and allocates the type-specific PK subcontext.
00194  *
00195  * \param ctx       Context to initialize. Must be empty (type NONE).
00196  * \param info      Information to use
00197  *
00198  * \return          0 on success,
00199  *                  MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input,
00200  *                  MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
00201  *
00202  * \note            For contexts holding an RSA-alt key, use
00203  *                  \c mbedtls_pk_setup_rsa_alt() instead.
00204  */
00205 int mbedtls_pk_setup( mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info );
00206 
00207 #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
00208 /**
00209  * \brief           Initialize an RSA-alt context
00210  *
00211  * \param ctx       Context to initialize. Must be empty (type NONE).
00212  * \param key       RSA key pointer
00213  * \param decrypt_func  Decryption function
00214  * \param sign_func     Signing function
00215  * \param key_len_func  Function returning key length in bytes
00216  *
00217  * \return          0 on success, or MBEDTLS_ERR_PK_BAD_INPUT_DATA if the
00218  *                  context wasn't already initialized as RSA_ALT.
00219  *
00220  * \note            This function replaces \c mbedtls_pk_setup() for RSA-alt.
00221  */
00222 int mbedtls_pk_setup_rsa_alt( mbedtls_pk_context *ctx, void * key,
00223                          mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
00224                          mbedtls_pk_rsa_alt_sign_func sign_func,
00225                          mbedtls_pk_rsa_alt_key_len_func key_len_func );
00226 #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
00227 
00228 /**
00229  * \brief           Get the size in bits of the underlying key
00230  *
00231  * \param ctx       Context to use
00232  *
00233  * \return          Key size in bits, or 0 on error
00234  */
00235 size_t mbedtls_pk_get_bitlen( const mbedtls_pk_context *ctx );
00236 
00237 /**
00238  * \brief           Get the length in bytes of the underlying key
00239  * \param ctx       Context to use
00240  *
00241  * \return          Key length in bytes, or 0 on error
00242  */
00243 static inline size_t mbedtls_pk_get_len( const mbedtls_pk_context *ctx )
00244 {
00245     return( ( mbedtls_pk_get_bitlen( ctx ) + 7 ) / 8 );
00246 }
00247 
00248 /**
00249  * \brief           Tell if a context can do the operation given by type
00250  *
00251  * \param ctx       Context to test
00252  * \param type      Target type
00253  *
00254  * \return          0 if context can't do the operations,
00255  *                  1 otherwise.
00256  */
00257 int mbedtls_pk_can_do( const mbedtls_pk_context *ctx, mbedtls_pk_type_t type );
00258 
00259 /**
00260  * \brief           Verify signature (including padding if relevant).
00261  *
00262  * \param ctx       PK context to use
00263  * \param md_alg    Hash algorithm used (see notes)
00264  * \param hash      Hash of the message to sign
00265  * \param hash_len  Hash length or 0 (see notes)
00266  * \param sig       Signature to verify
00267  * \param sig_len   Signature length
00268  *
00269  * \return          0 on success (signature is valid),
00270  *                  MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if the signature is
00271  *                  valid but its actual length is less than sig_len,
00272  *                  or a specific error code.
00273  *
00274  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
00275  *                  Use \c mbedtls_pk_verify_ext( MBEDTLS_PK_RSASSA_PSS, ... )
00276  *                  to verify RSASSA_PSS signatures.
00277  *
00278  * \note            If hash_len is 0, then the length associated with md_alg
00279  *                  is used instead, or an error returned if it is invalid.
00280  *
00281  * \note            md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
00282  */
00283 int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
00284                const unsigned char *hash, size_t hash_len,
00285                const unsigned char *sig, size_t sig_len );
00286 
00287 /**
00288  * \brief           Verify signature, with options.
00289  *                  (Includes verification of the padding depending on type.)
00290  *
00291  * \param type      Signature type (inc. possible padding type) to verify
00292  * \param options   Pointer to type-specific options, or NULL
00293  * \param ctx       PK context to use
00294  * \param md_alg    Hash algorithm used (see notes)
00295  * \param hash      Hash of the message to sign
00296  * \param hash_len  Hash length or 0 (see notes)
00297  * \param sig       Signature to verify
00298  * \param sig_len   Signature length
00299  *
00300  * \return          0 on success (signature is valid),
00301  *                  MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be
00302  *                  used for this type of signatures,
00303  *                  MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if the signature is
00304  *                  valid but its actual length is less than sig_len,
00305  *                  or a specific error code.
00306  *
00307  * \note            If hash_len is 0, then the length associated with md_alg
00308  *                  is used instead, or an error returned if it is invalid.
00309  *
00310  * \note            md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
00311  *
00312  * \note            If type is MBEDTLS_PK_RSASSA_PSS, then options must point
00313  *                  to a mbedtls_pk_rsassa_pss_options structure,
00314  *                  otherwise it must be NULL.
00315  */
00316 int mbedtls_pk_verify_ext( mbedtls_pk_type_t type, const void *options,
00317                    mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
00318                    const unsigned char *hash, size_t hash_len,
00319                    const unsigned char *sig, size_t sig_len );
00320 
00321 /**
00322  * \brief           Make signature, including padding if relevant.
00323  *
00324  * \param ctx       PK context to use - must hold a private key
00325  * \param md_alg    Hash algorithm used (see notes)
00326  * \param hash      Hash of the message to sign
00327  * \param hash_len  Hash length or 0 (see notes)
00328  * \param sig       Place to write the signature
00329  * \param sig_len   Number of bytes written
00330  * \param f_rng     RNG function
00331  * \param p_rng     RNG parameter
00332  *
00333  * \return          0 on success, or a specific error code.
00334  *
00335  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
00336  *                  There is no interface in the PK module to make RSASSA-PSS
00337  *                  signatures yet.
00338  *
00339  * \note            If hash_len is 0, then the length associated with md_alg
00340  *                  is used instead, or an error returned if it is invalid.
00341  *
00342  * \note            For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0.
00343  *                  For ECDSA, md_alg may never be MBEDTLS_MD_NONE.
00344  */
00345 int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
00346              const unsigned char *hash, size_t hash_len,
00347              unsigned char *sig, size_t *sig_len,
00348              int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00349 
00350 /**
00351  * \brief           Decrypt message (including padding if relevant).
00352  *
00353  * \param ctx       PK context to use - must hold a private key
00354  * \param input     Input to decrypt
00355  * \param ilen      Input size
00356  * \param output    Decrypted output
00357  * \param olen      Decrypted message length
00358  * \param osize     Size of the output buffer
00359  * \param f_rng     RNG function
00360  * \param p_rng     RNG parameter
00361  *
00362  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
00363  *
00364  * \return          0 on success, or a specific error code.
00365  */
00366 int mbedtls_pk_decrypt( mbedtls_pk_context *ctx,
00367                 const unsigned char *input, size_t ilen,
00368                 unsigned char *output, size_t *olen, size_t osize,
00369                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00370 
00371 /**
00372  * \brief           Encrypt message (including padding if relevant).
00373  *
00374  * \param ctx       PK context to use
00375  * \param input     Message to encrypt
00376  * \param ilen      Message size
00377  * \param output    Encrypted output
00378  * \param olen      Encrypted output length
00379  * \param osize     Size of the output buffer
00380  * \param f_rng     RNG function
00381  * \param p_rng     RNG parameter
00382  *
00383  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
00384  *
00385  * \return          0 on success, or a specific error code.
00386  */
00387 int mbedtls_pk_encrypt( mbedtls_pk_context *ctx,
00388                 const unsigned char *input, size_t ilen,
00389                 unsigned char *output, size_t *olen, size_t osize,
00390                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
00391 
00392 /**
00393  * \brief           Check if a public-private pair of keys matches.
00394  *
00395  * \param pub       Context holding a public key.
00396  * \param prv       Context holding a private (and public) key.
00397  *
00398  * \return          0 on success or MBEDTLS_ERR_PK_BAD_INPUT_DATA
00399  */
00400 int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv );
00401 
00402 /**
00403  * \brief           Export debug information
00404  *
00405  * \param ctx       Context to use
00406  * \param items     Place to write debug items
00407  *
00408  * \return          0 on success or MBEDTLS_ERR_PK_BAD_INPUT_DATA
00409  */
00410 int mbedtls_pk_debug( const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items );
00411 
00412 /**
00413  * \brief           Access the type name
00414  *
00415  * \param ctx       Context to use
00416  *
00417  * \return          Type name on success, or "invalid PK"
00418  */
00419 const char * mbedtls_pk_get_name( const mbedtls_pk_context *ctx );
00420 
00421 /**
00422  * \brief           Get the key type
00423  *
00424  * \param ctx       Context to use
00425  *
00426  * \return          Type on success, or MBEDTLS_PK_NONE
00427  */
00428 mbedtls_pk_type_t mbedtls_pk_get_type( const mbedtls_pk_context *ctx );
00429 
00430 #if defined(MBEDTLS_PK_PARSE_C)
00431 /** \ingroup pk_module */
00432 /**
00433  * \brief           Parse a private key in PEM or DER format
00434  *
00435  * \param ctx       key to be initialized
00436  * \param key       input buffer
00437  * \param keylen    size of the buffer
00438  *                  (including the terminating null byte for PEM data)
00439  * \param pwd       password for decryption (optional)
00440  * \param pwdlen    size of the password
00441  *
00442  * \note            On entry, ctx must be empty, either freshly initialised
00443  *                  with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
00444  *                  specific key type, check the result with mbedtls_pk_can_do().
00445  *
00446  * \note            The key is also checked for correctness.
00447  *
00448  * \return          0 if successful, or a specific PK or PEM error code
00449  */
00450 int mbedtls_pk_parse_key( mbedtls_pk_context *ctx,
00451                   const unsigned char *key, size_t keylen,
00452                   const unsigned char *pwd, size_t pwdlen );
00453 
00454 /** \ingroup pk_module */
00455 /**
00456  * \brief           Parse a public key in PEM or DER format
00457  *
00458  * \param ctx       key to be initialized
00459  * \param key       input buffer
00460  * \param keylen    size of the buffer
00461  *                  (including the terminating null byte for PEM data)
00462  *
00463  * \note            On entry, ctx must be empty, either freshly initialised
00464  *                  with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
00465  *                  specific key type, check the result with mbedtls_pk_can_do().
00466  *
00467  * \note            The key is also checked for correctness.
00468  *
00469  * \return          0 if successful, or a specific PK or PEM error code
00470  */
00471 int mbedtls_pk_parse_public_key( mbedtls_pk_context *ctx,
00472                          const unsigned char *key, size_t keylen );
00473 
00474 #if defined(MBEDTLS_FS_IO)
00475 /** \ingroup pk_module */
00476 /**
00477  * \brief           Load and parse a private key
00478  *
00479  * \param ctx       key to be initialized
00480  * \param path      filename to read the private key from
00481  * \param password  password to decrypt the file (can be NULL)
00482  *
00483  * \note            On entry, ctx must be empty, either freshly initialised
00484  *                  with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a
00485  *                  specific key type, check the result with mbedtls_pk_can_do().
00486  *
00487  * \note            The key is also checked for correctness.
00488  *
00489  * \return          0 if successful, or a specific PK or PEM error code
00490  */
00491 int mbedtls_pk_parse_keyfile( mbedtls_pk_context *ctx,
00492                       const char *path, const char *password );
00493 
00494 /** \ingroup pk_module */
00495 /**
00496  * \brief           Load and parse a public key
00497  *
00498  * \param ctx       key to be initialized
00499  * \param path      filename to read the public key from
00500  *
00501  * \note            On entry, ctx must be empty, either freshly initialised
00502  *                  with mbedtls_pk_init() or reset with mbedtls_pk_free(). If
00503  *                  you need a specific key type, check the result with
00504  *                  mbedtls_pk_can_do().
00505  *
00506  * \note            The key is also checked for correctness.
00507  *
00508  * \return          0 if successful, or a specific PK or PEM error code
00509  */
00510 int mbedtls_pk_parse_public_keyfile( mbedtls_pk_context *ctx, const char *path );
00511 #endif /* MBEDTLS_FS_IO */
00512 #endif /* MBEDTLS_PK_PARSE_C */
00513 
00514 #if defined(MBEDTLS_PK_WRITE_C)
00515 /**
00516  * \brief           Write a private key to a PKCS#1 or SEC1 DER structure
00517  *                  Note: data is written at the end of the buffer! Use the
00518  *                        return value to determine where you should start
00519  *                        using the buffer
00520  *
00521  * \param ctx       private to write away
00522  * \param buf       buffer to write to
00523  * \param size      size of the buffer
00524  *
00525  * \return          length of data written if successful, or a specific
00526  *                  error code
00527  */
00528 int mbedtls_pk_write_key_der( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
00529 
00530 /**
00531  * \brief           Write a public key to a SubjectPublicKeyInfo DER structure
00532  *                  Note: data is written at the end of the buffer! Use the
00533  *                        return value to determine where you should start
00534  *                        using the buffer
00535  *
00536  * \param ctx       public key to write away
00537  * \param buf       buffer to write to
00538  * \param size      size of the buffer
00539  *
00540  * \return          length of data written if successful, or a specific
00541  *                  error code
00542  */
00543 int mbedtls_pk_write_pubkey_der( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
00544 
00545 #if defined(MBEDTLS_PEM_WRITE_C)
00546 /**
00547  * \brief           Write a public key to a PEM string
00548  *
00549  * \param ctx       public key to write away
00550  * \param buf       buffer to write to
00551  * \param size      size of the buffer
00552  *
00553  * \return          0 if successful, or a specific error code
00554  */
00555 int mbedtls_pk_write_pubkey_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
00556 
00557 /**
00558  * \brief           Write a private key to a PKCS#1 or SEC1 PEM string
00559  *
00560  * \param ctx       private to write away
00561  * \param buf       buffer to write to
00562  * \param size      size of the buffer
00563  *
00564  * \return          0 if successful, or a specific error code
00565  */
00566 int mbedtls_pk_write_key_pem( mbedtls_pk_context *ctx, unsigned char *buf, size_t size );
00567 #endif /* MBEDTLS_PEM_WRITE_C */
00568 #endif /* MBEDTLS_PK_WRITE_C */
00569 
00570 /*
00571  * WARNING: Low-level functions. You probably do not want to use these unless
00572  *          you are certain you do ;)
00573  */
00574 
00575 #if defined(MBEDTLS_PK_PARSE_C)
00576 /**
00577  * \brief           Parse a SubjectPublicKeyInfo DER structure
00578  *
00579  * \param p         the position in the ASN.1 data
00580  * \param end       end of the buffer
00581  * \param pk        the key to fill
00582  *
00583  * \return          0 if successful, or a specific PK error code
00584  */
00585 int mbedtls_pk_parse_subpubkey( unsigned char **p, const unsigned char *end,
00586                         mbedtls_pk_context *pk );
00587 #endif /* MBEDTLS_PK_PARSE_C */
00588 
00589 #if defined(MBEDTLS_PK_WRITE_C)
00590 /**
00591  * \brief           Write a subjectPublicKey to ASN.1 data
00592  *                  Note: function works backwards in data buffer
00593  *
00594  * \param p         reference to current position pointer
00595  * \param start     start of the buffer (for bounds-checking)
00596  * \param key       public key to write away
00597  *
00598  * \return          the length written or a negative error code
00599  */
00600 int mbedtls_pk_write_pubkey( unsigned char **p, unsigned char *start,
00601                      const mbedtls_pk_context *key );
00602 #endif /* MBEDTLS_PK_WRITE_C */
00603 
00604 /*
00605  * Internal module functions. You probably do not want to use these unless you
00606  * know you do.
00607  */
00608 #if defined(MBEDTLS_FS_IO)
00609 int mbedtls_pk_load_file( const char *path, unsigned char **buf, size_t *n );
00610 #endif
00611 
00612 #ifdef __cplusplus
00613 }
00614 #endif
00615 
00616 #endif /* MBEDTLS_PK_H */