/** * \file pk.h * * \brief Public Key abstraction layer */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_PK_H #define MBEDTLS_PK_H #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include "mbedtls/md.h" #if defined(MBEDTLS_RSA_C) #include "mbedtls/rsa.h" #endif #if defined(MBEDTLS_ECP_C) #include "mbedtls/ecp.h" #endif #if defined(MBEDTLS_ECDSA_C) #include "mbedtls/ecdsa.h" #endif #if defined(MBEDTLS_PSA_CRYPTO_CLIENT) #include "psa/crypto.h" #endif /** Memory allocation failed. */ #define MBEDTLS_ERR_PK_ALLOC_FAILED -0x3F80 /** Type mismatch, eg attempt to encrypt with an ECDSA key */ #define MBEDTLS_ERR_PK_TYPE_MISMATCH -0x3F00 /** Bad input parameters to function. */ #define MBEDTLS_ERR_PK_BAD_INPUT_DATA -0x3E80 /** Read/write of file failed. */ #define MBEDTLS_ERR_PK_FILE_IO_ERROR -0x3E00 /** Unsupported key version */ #define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80 /** Invalid key tag or value. */ #define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT -0x3D00 /** Key algorithm is unsupported (only RSA and EC are supported). */ #define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG -0x3C80 /** Private key password can't be empty. */ #define MBEDTLS_ERR_PK_PASSWORD_REQUIRED -0x3C00 /** Given private key password does not allow for correct decryption. */ #define MBEDTLS_ERR_PK_PASSWORD_MISMATCH -0x3B80 /** The pubkey tag or value is invalid (only RSA and EC are supported). */ #define MBEDTLS_ERR_PK_INVALID_PUBKEY -0x3B00 /** The algorithm tag or value is invalid. */ #define MBEDTLS_ERR_PK_INVALID_ALG -0x3A80 /** Elliptic curve is unsupported (only NIST curves are supported). */ #define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00 /** Unavailable feature, e.g. RSA disabled for RSA key. */ #define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980 /** The buffer contains a valid signature followed by more data. */ #define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH -0x3900 /** The output buffer is too small. */ #define MBEDTLS_ERR_PK_BUFFER_TOO_SMALL -0x3880 #ifdef __cplusplus extern "C" { #endif /** * \brief Public key types */ typedef enum { MBEDTLS_PK_NONE=0, MBEDTLS_PK_RSA, MBEDTLS_PK_ECKEY, MBEDTLS_PK_ECKEY_DH, MBEDTLS_PK_ECDSA, MBEDTLS_PK_RSA_ALT, MBEDTLS_PK_RSASSA_PSS, MBEDTLS_PK_OPAQUE, } mbedtls_pk_type_t; /** * \brief Options for RSASSA-PSS signature verification. * See \c mbedtls_rsa_rsassa_pss_verify_ext() */ typedef struct mbedtls_pk_rsassa_pss_options { /** The digest to use for MGF1 in PSS. * * \note When #MBEDTLS_USE_PSA_CRYPTO is enabled and #MBEDTLS_RSA_C is * disabled, this must be equal to the \c md_alg argument passed * to mbedtls_pk_verify_ext(). In a future version of the library, * this constraint may apply whenever #MBEDTLS_USE_PSA_CRYPTO is * enabled regardless of the status of #MBEDTLS_RSA_C. */ mbedtls_md_type_t mgf1_hash_id; /** The expected length of the salt, in bytes. This may be * #MBEDTLS_RSA_SALT_LEN_ANY to accept any salt length. * * \note When #MBEDTLS_USE_PSA_CRYPTO is enabled, only * #MBEDTLS_RSA_SALT_LEN_ANY is valid. Any other value may be * ignored (allowing any salt length). */ int expected_salt_len; } mbedtls_pk_rsassa_pss_options; /** * \brief Maximum size of a signature made by mbedtls_pk_sign(). */ /* We need to set MBEDTLS_PK_SIGNATURE_MAX_SIZE to the maximum signature * size among the supported signature types. Do it by starting at 0, * then incrementally increasing to be large enough for each supported * signature mechanism. * * The resulting value can be 0, for example if MBEDTLS_ECDH_C is enabled * (which allows the pk module to be included) but neither MBEDTLS_ECDSA_C * nor MBEDTLS_RSA_C nor any opaque signature mechanism (PSA or RSA_ALT). */ #define MBEDTLS_PK_SIGNATURE_MAX_SIZE 0 #if (defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_RSA_ALT_SUPPORT)) && \ MBEDTLS_MPI_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE /* For RSA, the signature can be as large as the bignum module allows. * For RSA_ALT, the signature size is not necessarily tied to what the * bignum module can do, but in the absence of any specific setting, * we use that (rsa_alt_sign_wrap in library/pk_wrap.h will check). */ #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE #define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE #endif #if defined(MBEDTLS_ECDSA_C) && \ MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_PK_SIGNATURE_MAX_SIZE /* For ECDSA, the ecdsa module exports a constant for the maximum * signature size. */ #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE #define MBEDTLS_PK_SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN #endif #if defined(MBEDTLS_USE_PSA_CRYPTO) #if PSA_SIGNATURE_MAX_SIZE > MBEDTLS_PK_SIGNATURE_MAX_SIZE /* PSA_SIGNATURE_MAX_SIZE is the maximum size of a signature made * through the PSA API in the PSA representation. */ #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE #define MBEDTLS_PK_SIGNATURE_MAX_SIZE PSA_SIGNATURE_MAX_SIZE #endif #if PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11 > MBEDTLS_PK_SIGNATURE_MAX_SIZE /* The Mbed TLS representation is different for ECDSA signatures: * PSA uses the raw concatenation of r and s, * whereas Mbed TLS uses the ASN.1 representation (SEQUENCE of two INTEGERs). * Add the overhead of ASN.1: up to (1+2) + 2 * (1+2+1) for the * types, lengths (represented by up to 2 bytes), and potential leading * zeros of the INTEGERs and the SEQUENCE. */ #undef MBEDTLS_PK_SIGNATURE_MAX_SIZE #define MBEDTLS_PK_SIGNATURE_MAX_SIZE (PSA_VENDOR_ECDSA_SIGNATURE_MAX_SIZE + 11) #endif #endif /* defined(MBEDTLS_USE_PSA_CRYPTO) */ /* Internal helper to define which fields in the pk_context structure below * should be used for EC keys: legacy ecp_keypair or the raw (PSA friendly) * format. It should be noted that this only affects how data is stored, not * which functions are used for various operations. The overall picture looks * like this: * - if USE_PSA is not defined and ECP_C is defined then use ecp_keypair data * structure and legacy functions * - if USE_PSA is defined and * - if ECP_C then use ecp_keypair structure, convert data to a PSA friendly * format and use PSA functions * - if !ECP_C then use new raw data and PSA functions directly. * * The main reason for the "intermediate" (USE_PSA + ECP_C) above is that as long * as ECP_C is defined mbedtls_pk_ec() gives the user a read/write access to the * ecp_keypair structure inside the pk_context so they can modify it using * ECP functions which are not under PK module's control. */ #if defined(MBEDTLS_USE_PSA_CRYPTO) && defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY) && \ !defined(MBEDTLS_ECP_C) #define MBEDTLS_PK_USE_PSA_EC_DATA #endif /** * \brief Types for interfacing with the debug module */ typedef enum { MBEDTLS_PK_DEBUG_NONE = 0, MBEDTLS_PK_DEBUG_MPI, MBEDTLS_PK_DEBUG_ECP, MBEDTLS_PK_DEBUG_PSA_EC, } mbedtls_pk_debug_type; /** * \brief Item to send to the debug module */ typedef struct mbedtls_pk_debug_item { mbedtls_pk_debug_type MBEDTLS_PRIVATE(type); const char *MBEDTLS_PRIVATE(name); void *MBEDTLS_PRIVATE(value); } mbedtls_pk_debug_item; /** Maximum number of item send for debugging, plus 1 */ #define MBEDTLS_PK_DEBUG_MAX_ITEMS 3 /** * \brief Public key information and operations * * \note The library does not support custom pk info structures, * only built-in structures returned by * mbedtls_cipher_info_from_type(). */ typedef struct mbedtls_pk_info_t mbedtls_pk_info_t; #define MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN \ PSA_KEY_EXPORT_ECC_PUBLIC_KEY_MAX_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS) /** * \brief Public key container */ typedef struct mbedtls_pk_context { const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info); /**< Public key information */ void *MBEDTLS_PRIVATE(pk_ctx); /**< Underlying public key context */ /* The following field is used to store the ID of a private key in the * following cases: * - opaque key when MBEDTLS_USE_PSA_CRYPTO is defined * - normal key when MBEDTLS_PK_USE_PSA_EC_DATA is defined. In this case: * - the pk_ctx above is not not used to store the private key anymore. * Actually that field not populated at all in this case because also * the public key will be stored in raw format as explained below * - this ID is used for all private key operations (ex: sign, check * key pair, key write, etc) using PSA functions * * Note: this private key storing solution only affects EC keys, not the * other ones. The latters still use the pk_ctx to store their own * context. */ #if defined(MBEDTLS_USE_PSA_CRYPTO) mbedtls_svc_key_id_t MBEDTLS_PRIVATE(priv_id); /**< Key ID for opaque keys */ #endif /* MBEDTLS_USE_PSA_CRYPTO */ /* The following fields are meant for storing the public key in raw format * which is handy for: * - easily importing it into the PSA context * - reducing the ECP module dependencies in the PK one. * * When MBEDTLS_PK_USE_PSA_EC_DATA is enabled: * - the pk_ctx above is not used anymore for storing the public key * inside the ecp_keypair structure * - the following fields are used for all public key operations: signature * verify, key pair check and key write. * - For a key pair, priv_id contains the private key. For a public key, * priv_id is null. * Of course, when MBEDTLS_PK_USE_PSA_EC_DATA is not enabled, the legacy * ecp_keypair structure is used for storing the public key and performing * all the operations. * * Note: This new public key storing solution only works for EC keys, not * other ones. The latters still use pk_ctx to store their own * context. */ #if defined(MBEDTLS_PK_USE_PSA_EC_DATA) uint8_t MBEDTLS_PRIVATE(pub_raw)[MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN]; /**< Raw public key */ size_t MBEDTLS_PRIVATE(pub_raw_len); /**< Valid bytes in "pub_raw" */ psa_ecc_family_t MBEDTLS_PRIVATE(ec_family); /**< EC family of pk */ size_t MBEDTLS_PRIVATE(ec_bits); /**< Curve's bits of pk */ #endif /* MBEDTLS_PK_USE_PSA_EC_DATA */ } mbedtls_pk_context; #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE) /** * \brief Context for resuming operations */ typedef struct { const mbedtls_pk_info_t *MBEDTLS_PRIVATE(pk_info); /**< Public key information */ void *MBEDTLS_PRIVATE(rs_ctx); /**< Underlying restart context */ } mbedtls_pk_restart_ctx; #else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */ /* Now we can declare functions that take a pointer to that */ typedef void mbedtls_pk_restart_ctx; #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */ #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT) /** * \brief Types for RSA-alt abstraction */ typedef int (*mbedtls_pk_rsa_alt_decrypt_func)(void *ctx, size_t *olen, const unsigned char *input, unsigned char *output, size_t output_max_len); typedef int (*mbedtls_pk_rsa_alt_sign_func)(void *ctx, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, mbedtls_md_type_t md_alg, unsigned int hashlen, const unsigned char *hash, unsigned char *sig); typedef size_t (*mbedtls_pk_rsa_alt_key_len_func)(void *ctx); #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */ /** * \brief Return information associated with the given PK type * * \param pk_type PK type to search for. * * \return The PK info associated with the type or NULL if not found. */ const mbedtls_pk_info_t *mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type); /** * \brief Initialize a #mbedtls_pk_context (as NONE). * * \param ctx The context to initialize. * This must not be \c NULL. */ void mbedtls_pk_init(mbedtls_pk_context *ctx); /** * \brief Free the components of a #mbedtls_pk_context. * * \param ctx The context to clear. It must have been initialized. * If this is \c NULL, this function does nothing. * * \note For contexts that have been set up with * mbedtls_pk_setup_opaque(), this does not free the underlying * PSA key and you still need to call psa_destroy_key() * independently if you want to destroy that key. */ void mbedtls_pk_free(mbedtls_pk_context *ctx); #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE) /** * \brief Initialize a restart context * * \param ctx The context to initialize. * This must not be \c NULL. */ void mbedtls_pk_restart_init(mbedtls_pk_restart_ctx *ctx); /** * \brief Free the components of a restart context * * \param ctx The context to clear. It must have been initialized. * If this is \c NULL, this function does nothing. */ void mbedtls_pk_restart_free(mbedtls_pk_restart_ctx *ctx); #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */ /** * \brief Initialize a PK context with the information given * and allocates the type-specific PK subcontext. * * \param ctx Context to initialize. It must not have been set * up yet (type #MBEDTLS_PK_NONE). * \param info Information to use * * \return 0 on success, * MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input, * MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure. * * \note For contexts holding an RSA-alt key, use * \c mbedtls_pk_setup_rsa_alt() instead. */ int mbedtls_pk_setup(mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info); #if defined(MBEDTLS_USE_PSA_CRYPTO) /** * \brief Initialize a PK context to wrap a PSA key. * * \note This function replaces mbedtls_pk_setup() for contexts * that wrap a (possibly opaque) PSA key instead of * storing and manipulating the key material directly. * * \param ctx The context to initialize. It must be empty (type NONE). * \param key The PSA key to wrap, which must hold an ECC or RSA key * pair (see notes below). * * \note The wrapped key must remain valid as long as the * wrapping PK context is in use, that is at least between * the point this function is called and the point * mbedtls_pk_free() is called on this context. The wrapped * key might then be independently used or destroyed. * * \note This function is currently only available for ECC or RSA * key pairs (that is, keys containing private key material). * Support for other key types may be added later. * * \return \c 0 on success. * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input * (context already used, invalid key identifier). * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the key is not an * ECC key pair. * \return #MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure. */ int mbedtls_pk_setup_opaque(mbedtls_pk_context *ctx, const mbedtls_svc_key_id_t key); #endif /* MBEDTLS_USE_PSA_CRYPTO */ #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT) /** * \brief Initialize an RSA-alt context * * \param ctx Context to initialize. It must not have been set * up yet (type #MBEDTLS_PK_NONE). * \param key RSA key pointer * \param decrypt_func Decryption function * \param sign_func Signing function * \param key_len_func Function returning key length in bytes * * \return 0 on success, or MBEDTLS_ERR_PK_BAD_INPUT_DATA if the * context wasn't already initialized as RSA_ALT. * * \note This function replaces \c mbedtls_pk_setup() for RSA-alt. */ int mbedtls_pk_setup_rsa_alt(mbedtls_pk_context *ctx, void *key, mbedtls_pk_rsa_alt_decrypt_func decrypt_func, mbedtls_pk_rsa_alt_sign_func sign_func, mbedtls_pk_rsa_alt_key_len_func key_len_func); #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */ /** * \brief Get the size in bits of the underlying key * * \param ctx The context to query. It must have been initialized. * * \return Key size in bits, or 0 on error */ size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context *ctx); /** * \brief Get the length in bytes of the underlying key * * \param ctx The context to query. It must have been initialized. * * \return Key length in bytes, or 0 on error */ static inline size_t mbedtls_pk_get_len(const mbedtls_pk_context *ctx) { return (mbedtls_pk_get_bitlen(ctx) + 7) / 8; } /** * \brief Tell if a context can do the operation given by type * * \param ctx The context to query. It must have been initialized. * \param type The desired type. * * \return 1 if the context can do operations on the given type. * \return 0 if the context cannot do the operations on the given * type. This is always the case for a context that has * been initialized but not set up, or that has been * cleared with mbedtls_pk_free(). */ int mbedtls_pk_can_do(const mbedtls_pk_context *ctx, mbedtls_pk_type_t type); #if defined(MBEDTLS_USE_PSA_CRYPTO) /** * \brief Tell if context can do the operation given by PSA algorithm * * \param ctx The context to query. It must have been initialized. * \param alg PSA algorithm to check against, the following are allowed: * PSA_ALG_RSA_PKCS1V15_SIGN(hash), * PSA_ALG_RSA_PSS(hash), * PSA_ALG_RSA_PKCS1V15_CRYPT, * PSA_ALG_ECDSA(hash), * PSA_ALG_ECDH, where hash is a specific hash. * \param usage PSA usage flag to check against, must be composed of: * PSA_KEY_USAGE_SIGN_HASH * PSA_KEY_USAGE_DECRYPT * PSA_KEY_USAGE_DERIVE. * Context key must match all passed usage flags. * * \warning Since the set of allowed algorithms and usage flags may be * expanded in the future, the return value \c 0 should not * be taken in account for non-allowed algorithms and usage * flags. * * \return 1 if the context can do operations on the given type. * \return 0 if the context cannot do the operations on the given * type, for non-allowed algorithms and usage flags, or * for a context that has been initialized but not set up * or that has been cleared with mbedtls_pk_free(). */ int mbedtls_pk_can_do_ext(const mbedtls_pk_context *ctx, psa_algorithm_t alg, psa_key_usage_t usage); #endif /* MBEDTLS_USE_PSA_CRYPTO */ #if defined(MBEDTLS_PSA_CRYPTO_CLIENT) /** * \brief Determine valid PSA attributes that can be used to * import a key into PSA. * * The attributes determined by this function are suitable * for calling mbedtls_pk_import_into_psa() to create * a PSA key with the same key material. * * The typical flow of operations involving this function is * ``` * psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; * int ret = mbedtls_pk_get_psa_attributes(pk, &attributes); * if (ret != 0) ...; // error handling omitted * // Tweak attributes if desired * psa_key_id_t key_id = 0; * ret = mbedtls_pk_import_into_psa(pk, &attributes, &key_id); * if (ret != 0) ...; // error handling omitted * ``` * * \note This function does not support RSA-alt contexts * (set up with mbedtls_pk_setup_rsa_alt()). * * \param[in] pk The PK context to use. It must have been set up. * It can either contain a key pair or just a public key. * \param usage A single `PSA_KEY_USAGE_xxx` flag among the following: * - #PSA_KEY_USAGE_DECRYPT: \p pk must contain a * key pair. The output \p attributes will contain a * key pair type, and the usage policy will allow * #PSA_KEY_USAGE_ENCRYPT as well as * #PSA_KEY_USAGE_DECRYPT. * - #PSA_KEY_USAGE_DERIVE: \p pk must contain a * key pair. The output \p attributes will contain a * key pair type. * - #PSA_KEY_USAGE_ENCRYPT: The output * \p attributes will contain a public key type. * - #PSA_KEY_USAGE_SIGN_HASH: \p pk must contain a * key pair. The output \p attributes will contain a * key pair type, and the usage policy will allow * #PSA_KEY_USAGE_VERIFY_HASH as well as * #PSA_KEY_USAGE_SIGN_HASH. * - #PSA_KEY_USAGE_SIGN_MESSAGE: \p pk must contain a * key pair. The output \p attributes will contain a * key pair type, and the usage policy will allow * #PSA_KEY_USAGE_VERIFY_MESSAGE as well as * #PSA_KEY_USAGE_SIGN_MESSAGE. * - #PSA_KEY_USAGE_VERIFY_HASH: The output * \p attributes will contain a public key type. * - #PSA_KEY_USAGE_VERIFY_MESSAGE: The output * \p attributes will contain a public key type. * \param[out] attributes * On success, valid attributes to import the key into PSA. * - The lifetime and key identifier are unchanged. If the * attribute structure was initialized or reset before * calling this function, this will result in a volatile * key. Call psa_set_key_identifier() before or after this * function if you wish to create a persistent key. Call * psa_set_key_lifetime() before or after this function if * you wish to import the key in a secure element. * - The key type and bit-size are determined by the contents * of the PK context. If the PK context contains a key * pair, the key type can be either a key pair type or * the corresponding public key type, depending on * \p usage. If the PK context contains a public key, * the key type is a public key type. * - The key's policy is determined by the key type and * the \p usage parameter. The usage always allows * \p usage, exporting and copying the key, and * possibly other permissions as documented for the * \p usage parameter. * The permitted algorithm policy is determined as follows * based on the #mbedtls_pk_type_t type of \p pk, * the chosen \p usage and other factors: * - #MBEDTLS_PK_RSA whose underlying * #mbedtls_rsa_context has the padding mode * #MBEDTLS_RSA_PKCS_V15: * #PSA_ALG_RSA_PKCS1V15_SIGN(#PSA_ALG_ANY_HASH) * if \p usage is SIGN/VERIFY, and * #PSA_ALG_RSA_PKCS1V15_CRYPT * if \p usage is ENCRYPT/DECRYPT. * - #MBEDTLS_PK_RSA whose underlying * #mbedtls_rsa_context has the padding mode * #MBEDTLS_RSA_PKCS_V21 and the digest type * corresponding to the PSA algorithm \c hash: * #PSA_ALG_RSA_PSS_ANY_SALT(#PSA_ALG_ANY_HASH) * if \p usage is SIGN/VERIFY, and * #PSA_ALG_RSA_OAEP(\c hash) * if \p usage is ENCRYPT/DECRYPT. * - #MBEDTLS_PK_RSA_ALT: not supported. * - #MBEDTLS_PK_ECDSA or #MBEDTLS_PK_ECKEY * if \p usage is SIGN/VERIFY: * #PSA_ALG_DETERMINISTIC_ECDSA(#PSA_ALG_ANY_HASH) * if #MBEDTLS_ECDSA_DETERMINISTIC is enabled, * otherwise #PSA_ALG_ECDSA(#PSA_ALG_ANY_HASH). * - #MBEDTLS_PK_ECKEY_DH or #MBEDTLS_PK_ECKEY * if \p usage is DERIVE: * #PSA_ALG_ECDH. * - #MBEDTLS_PK_OPAQUE: same as the primary algorithm * set for the underlying PSA key, except that * sign/decrypt flags are removed if the type is * set to a public key type. * The underlying key must allow \p usage. * Note that the enrollment algorithm set with * psa_set_key_enrollment_algorithm() is not copied. * * \return 0 on success. * #MBEDTLS_ERR_PK_TYPE_MISMATCH if \p pk does not contain * a key of the type identified in \p attributes. * Another error code on other failures. */ int mbedtls_pk_get_psa_attributes(const mbedtls_pk_context *pk, psa_key_usage_t usage, psa_key_attributes_t *attributes); /** * \brief Import a key into the PSA key store. * * This function is equivalent to calling psa_import_key() * with the key material from \p pk. * * The typical way to use this function is: * -# Call mbedtls_pk_get_psa_attributes() to obtain * attributes for the given key. * -# If desired, modify the attributes, for example: * - To create a persistent key, call * psa_set_key_identifier() and optionally * psa_set_key_lifetime(). * - To import only the public part of a key pair: * * psa_set_key_type(&attributes, * PSA_KEY_TYPE_PUBLIC_KEY_OF_KEY_PAIR( * psa_get_key_type(&attributes))); * - Restrict the key usage if desired. * -# Call mbedtls_pk_import_into_psa(). * * \note This function does not support RSA-alt contexts * (set up with mbedtls_pk_setup_rsa_alt()). * * \param[in] pk The PK context to use. It must have been set up. * It can either contain a key pair or just a public key. * \param[in] attributes * The attributes to use for the new key. They must be * compatible with \p pk. In particular, the key type * must match the content of \p pk. * If \p pk contains a key pair, the key type in * attributes can be either the key pair type or the * corresponding public key type (to import only the * public part). * \param[out] key_id * On success, the identifier of the newly created key. * On error, this is #MBEDTLS_SVC_KEY_ID_INIT. * * \return 0 on success. * #MBEDTLS_ERR_PK_TYPE_MISMATCH if \p pk does not contain * a key of the type identified in \p attributes. * Another error code on other failures. */ int mbedtls_pk_import_into_psa(const mbedtls_pk_context *pk, const psa_key_attributes_t *attributes, mbedtls_svc_key_id_t *key_id); /** * \brief Create a PK context starting from a key stored in PSA. * This key: * - must be exportable and * - must be an RSA or EC key pair or public key (FFDH is not supported in PK). * * The resulting PK object will be a transparent type: * - #MBEDTLS_PK_RSA for RSA keys or * - #MBEDTLS_PK_ECKEY for EC keys. * * Once this functions returns the PK object will be completely * independent from the original PSA key that it was generated * from. * Calling mbedtls_pk_sign(), mbedtls_pk_verify(), * mbedtls_pk_encrypt(), mbedtls_pk_decrypt() on the resulting * PK context will perform the corresponding algorithm for that * PK context type. * * For ECDSA, the choice of deterministic vs randomized will * be based on the compile-time setting #MBEDTLS_ECDSA_DETERMINISTIC. * * For an RSA key, the output PK context will allow both * encrypt/decrypt and sign/verify regardless of the original * key's policy. * The original key's policy determines the output key's padding * mode: PCKS1 v2.1 is set if the PSA key policy is OAEP or PSS, * otherwise PKCS1 v1.5 is set. * * \param key_id The key identifier of the key stored in PSA. * \param pk The PK context that will be filled. It must be initialized, * but not set up. * * \return 0 on success. * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA in case the provided input * parameters are not correct. */ int mbedtls_pk_copy_from_psa(mbedtls_svc_key_id_t key_id, mbedtls_pk_context *pk); /** * \brief Create a PK context for the public key of a PSA key. * * The key must be an RSA or ECC key. It can be either a * public key or a key pair, and only the public key is copied. * The resulting PK object will be a transparent type: * - #MBEDTLS_PK_RSA for RSA keys or * - #MBEDTLS_PK_ECKEY for EC keys. * * Once this functions returns the PK object will be completely * independent from the original PSA key that it was generated * from. * Calling mbedtls_pk_verify() or * mbedtls_pk_encrypt() on the resulting * PK context will perform the corresponding algorithm for that * PK context type. * * For an RSA key, the output PK context will allow both * encrypt and verify regardless of the original key's policy. * The original key's policy determines the output key's padding * mode: PCKS1 v2.1 is set if the PSA key policy is OAEP or PSS, * otherwise PKCS1 v1.5 is set. * * \param key_id The key identifier of the key stored in PSA. * \param pk The PK context that will be filled. It must be initialized, * but not set up. * * \return 0 on success. * \return MBEDTLS_ERR_PK_BAD_INPUT_DATA in case the provided input * parameters are not correct. */ int mbedtls_pk_copy_public_from_psa(mbedtls_svc_key_id_t key_id, mbedtls_pk_context *pk); #endif /* MBEDTLS_PSA_CRYPTO_CLIENT */ /** * \brief Verify signature (including padding if relevant). * * \param ctx The PK context to use. It must have been set up. * \param md_alg Hash algorithm used. * This can be #MBEDTLS_MD_NONE if the signature algorithm * does not rely on a hash algorithm (non-deterministic * ECDSA, RSA PKCS#1 v1.5). * For PKCS#1 v1.5, if \p md_alg is #MBEDTLS_MD_NONE, then * \p hash is the DigestInfo structure used by RFC 8017 * §9.2 steps 3–6. If \p md_alg is a valid hash * algorithm then \p hash is the digest itself, and this * function calculates the DigestInfo encoding internally. * \param hash Hash of the message to sign * \param hash_len Hash length * \param sig Signature to verify * \param sig_len Signature length * * \note For keys of type #MBEDTLS_PK_RSA, the signature algorithm is * either PKCS#1 v1.5 or PSS (accepting any salt length), * depending on the padding mode in the underlying RSA context. * For a pk object constructed by parsing, this is PKCS#1 v1.5 * by default. Use mbedtls_pk_verify_ext() to explicitly select * a different algorithm. * * \return 0 on success (signature is valid), * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid * signature in \p sig but its length is less than \p sig_len, * or a specific error code. */ int mbedtls_pk_verify(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len); /** * \brief Restartable version of \c mbedtls_pk_verify() * * \note Performs the same job as \c mbedtls_pk_verify(), but can * return early and restart according to the limit set with * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC * operations. For RSA, same as \c mbedtls_pk_verify(). * * \param ctx The PK context to use. It must have been set up. * \param md_alg Hash algorithm used (see notes) * \param hash Hash of the message to sign * \param hash_len Hash length or 0 (see notes) * \param sig Signature to verify * \param sig_len Signature length * \param rs_ctx Restart context (NULL to disable restart) * * \return See \c mbedtls_pk_verify(), or * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of * operations was reached: see \c mbedtls_ecp_set_max_ops(). */ int mbedtls_pk_verify_restartable(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len, mbedtls_pk_restart_ctx *rs_ctx); /** * \brief Verify signature, with options. * (Includes verification of the padding depending on type.) * * \param type Signature type (inc. possible padding type) to verify * \param options Pointer to type-specific options, or NULL * \param ctx The PK context to use. It must have been set up. * \param md_alg Hash algorithm used (see notes) * \param hash Hash of the message to sign * \param hash_len Hash length or 0 (see notes) * \param sig Signature to verify * \param sig_len Signature length * * \return 0 on success (signature is valid), * #MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be * used for this type of signatures, * #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid * signature in \p sig but its length is less than \p sig_len, * or a specific error code. * * \note If hash_len is 0, then the length associated with md_alg * is used instead, or an error returned if it is invalid. * * \note md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0 * * \note If type is MBEDTLS_PK_RSASSA_PSS, then options must point * to a mbedtls_pk_rsassa_pss_options structure, * otherwise it must be NULL. Note that if * #MBEDTLS_USE_PSA_CRYPTO is defined, the salt length is not * verified as PSA_ALG_RSA_PSS_ANY_SALT is used. */ int mbedtls_pk_verify_ext(mbedtls_pk_type_t type, const void *options, mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, const unsigned char *sig, size_t sig_len); /** * \brief Make signature, including padding if relevant. * * \param ctx The PK context to use. It must have been set up * with a private key. * \param md_alg Hash algorithm used (see notes) * \param hash Hash of the message to sign * \param hash_len Hash length * \param sig Place to write the signature. * It must have enough room for the signature. * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough. * You may use a smaller buffer if it is large enough * given the key type. * \param sig_size The size of the \p sig buffer in bytes. * \param sig_len On successful return, * the number of bytes written to \p sig. * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * * \note For keys of type #MBEDTLS_PK_RSA, the signature algorithm is * either PKCS#1 v1.5 or PSS (using the largest possible salt * length up to the hash length), depending on the padding mode * in the underlying RSA context. For a pk object constructed * by parsing, this is PKCS#1 v1.5 by default. Use * mbedtls_pk_verify_ext() to explicitly select a different * algorithm. * * \return 0 on success, or a specific error code. * * \note For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0. * For ECDSA, md_alg may never be MBEDTLS_MD_NONE. */ int mbedtls_pk_sign(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, unsigned char *sig, size_t sig_size, size_t *sig_len, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief Make signature given a signature type. * * \param pk_type Signature type. * \param ctx The PK context to use. It must have been set up * with a private key. * \param md_alg Hash algorithm used (see notes) * \param hash Hash of the message to sign * \param hash_len Hash length * \param sig Place to write the signature. * It must have enough room for the signature. * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough. * You may use a smaller buffer if it is large enough * given the key type. * \param sig_size The size of the \p sig buffer in bytes. * \param sig_len On successful return, * the number of bytes written to \p sig. * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * * \return 0 on success, or a specific error code. * * \note When \p pk_type is #MBEDTLS_PK_RSASSA_PSS, * see #PSA_ALG_RSA_PSS for a description of PSS options used. * * \note For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0. * For ECDSA, md_alg may never be MBEDTLS_MD_NONE. * */ int mbedtls_pk_sign_ext(mbedtls_pk_type_t pk_type, mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, unsigned char *sig, size_t sig_size, size_t *sig_len, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief Restartable version of \c mbedtls_pk_sign() * * \note Performs the same job as \c mbedtls_pk_sign(), but can * return early and restart according to the limit set with * \c mbedtls_ecp_set_max_ops() to reduce blocking for ECC * operations. For RSA, same as \c mbedtls_pk_sign(). * * \param ctx The PK context to use. It must have been set up * with a private key. * \param md_alg Hash algorithm used (see notes for mbedtls_pk_sign()) * \param hash Hash of the message to sign * \param hash_len Hash length * \param sig Place to write the signature. * It must have enough room for the signature. * #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough. * You may use a smaller buffer if it is large enough * given the key type. * \param sig_size The size of the \p sig buffer in bytes. * \param sig_len On successful return, * the number of bytes written to \p sig. * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * \param rs_ctx Restart context (NULL to disable restart) * * \return See \c mbedtls_pk_sign(). * \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of * operations was reached: see \c mbedtls_ecp_set_max_ops(). */ int mbedtls_pk_sign_restartable(mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg, const unsigned char *hash, size_t hash_len, unsigned char *sig, size_t sig_size, size_t *sig_len, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, mbedtls_pk_restart_ctx *rs_ctx); /** * \brief Decrypt message (including padding if relevant). * * \param ctx The PK context to use. It must have been set up * with a private key. * \param input Input to decrypt * \param ilen Input size * \param output Decrypted output * \param olen Decrypted message length * \param osize Size of the output buffer * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * * \note For keys of type #MBEDTLS_PK_RSA, the signature algorithm is * either PKCS#1 v1.5 or OAEP, depending on the padding mode in * the underlying RSA context. For a pk object constructed by * parsing, this is PKCS#1 v1.5 by default. * * \return 0 on success, or a specific error code. */ int mbedtls_pk_decrypt(mbedtls_pk_context *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, size_t osize, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief Encrypt message (including padding if relevant). * * \param ctx The PK context to use. It must have been set up. * \param input Message to encrypt * \param ilen Message size * \param output Encrypted output * \param olen Encrypted output length * \param osize Size of the output buffer * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * * \note For keys of type #MBEDTLS_PK_RSA, the signature algorithm is * either PKCS#1 v1.5 or OAEP, depending on the padding mode in * the underlying RSA context. For a pk object constructed by * parsing, this is PKCS#1 v1.5 by default. * * \note \p f_rng is used for padding generation. * * \return 0 on success, or a specific error code. */ int mbedtls_pk_encrypt(mbedtls_pk_context *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, size_t osize, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief Check if a public-private pair of keys matches. * * \param pub Context holding a public key. * \param prv Context holding a private (and public) key. * \param f_rng RNG function, must not be \c NULL. * \param p_rng RNG parameter * * \return \c 0 on success (keys were checked and match each other). * \return #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the keys could not * be checked - in that case they may or may not match. * \return #MBEDTLS_ERR_PK_BAD_INPUT_DATA if a context is invalid. * \return Another non-zero value if the keys do not match. */ int mbedtls_pk_check_pair(const mbedtls_pk_context *pub, const mbedtls_pk_context *prv, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** * \brief Export debug information * * \param ctx The PK context to use. It must have been initialized. * \param items Place to write debug items * * \return 0 on success or MBEDTLS_ERR_PK_BAD_INPUT_DATA */ int mbedtls_pk_debug(const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items); /** * \brief Access the type name * * \param ctx The PK context to use. It must have been initialized. * * \return Type name on success, or "invalid PK" */ const char *mbedtls_pk_get_name(const mbedtls_pk_context *ctx); /** * \brief Get the key type * * \param ctx The PK context to use. It must have been initialized. * * \return Type on success. * \return #MBEDTLS_PK_NONE for a context that has not been set up. */ mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context *ctx); #if defined(MBEDTLS_RSA_C) /** * Quick access to an RSA context inside a PK context. * * \warning This function can only be used when the type of the context, as * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_RSA. * Ensuring that is the caller's responsibility. * Alternatively, you can check whether this function returns NULL. * * \return The internal RSA context held by the PK context, or NULL. */ static inline mbedtls_rsa_context *mbedtls_pk_rsa(const mbedtls_pk_context pk) { switch (mbedtls_pk_get_type(&pk)) { case MBEDTLS_PK_RSA: return (mbedtls_rsa_context *) (pk).MBEDTLS_PRIVATE(pk_ctx); default: return NULL; } } #endif /* MBEDTLS_RSA_C */ #if defined(MBEDTLS_ECP_C) /** * Quick access to an EC context inside a PK context. * * \warning This function can only be used when the type of the context, as * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_ECKEY, * #MBEDTLS_PK_ECKEY_DH, or #MBEDTLS_PK_ECDSA. * Ensuring that is the caller's responsibility. * Alternatively, you can check whether this function returns NULL. * * \return The internal EC context held by the PK context, or NULL. */ static inline mbedtls_ecp_keypair *mbedtls_pk_ec(const mbedtls_pk_context pk) { switch (mbedtls_pk_get_type(&pk)) { case MBEDTLS_PK_ECKEY: case MBEDTLS_PK_ECKEY_DH: case MBEDTLS_PK_ECDSA: return (mbedtls_ecp_keypair *) (pk).MBEDTLS_PRIVATE(pk_ctx); default: return NULL; } } #endif /* MBEDTLS_ECP_C */ #if defined(MBEDTLS_PK_PARSE_C) /** \ingroup pk_module */ /** * \brief Parse a private key in PEM or DER format * * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto * subsystem must have been initialized by calling * psa_crypto_init() before calling this function. * * \param ctx The PK context to fill. It must have been initialized * but not set up. * \param key Input buffer to parse. * The buffer must contain the input exactly, with no * extra trailing material. For PEM, the buffer must * contain a null-terminated string. * \param keylen Size of \b key in bytes. * For PEM data, this includes the terminating null byte, * so \p keylen must be equal to `strlen(key) + 1`. * \param pwd Optional password for decryption. * Pass \c NULL if expecting a non-encrypted key. * Pass a string of \p pwdlen bytes if expecting an encrypted * key; a non-encrypted key will also be accepted. * The empty password is not supported. * \param pwdlen Size of the password in bytes. * Ignored if \p pwd is \c NULL. * \param f_rng RNG function, must not be \c NULL. Used for blinding. * \param p_rng RNG parameter * * \note On entry, ctx must be empty, either freshly initialised * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a * specific key type, check the result with mbedtls_pk_can_do(). * * \note The key is also checked for correctness. * * \return 0 if successful, or a specific PK or PEM error code */ int mbedtls_pk_parse_key(mbedtls_pk_context *ctx, const unsigned char *key, size_t keylen, const unsigned char *pwd, size_t pwdlen, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** \ingroup pk_module */ /** * \brief Parse a public key in PEM or DER format * * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto * subsystem must have been initialized by calling * psa_crypto_init() before calling this function. * * \param ctx The PK context to fill. It must have been initialized * but not set up. * \param key Input buffer to parse. * The buffer must contain the input exactly, with no * extra trailing material. For PEM, the buffer must * contain a null-terminated string. * \param keylen Size of \b key in bytes. * For PEM data, this includes the terminating null byte, * so \p keylen must be equal to `strlen(key) + 1`. * * \note On entry, ctx must be empty, either freshly initialised * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a * specific key type, check the result with mbedtls_pk_can_do(). * * \note For compressed points, see #MBEDTLS_ECP_PF_COMPRESSED for * limitations. * * \note The key is also checked for correctness. * * \return 0 if successful, or a specific PK or PEM error code */ int mbedtls_pk_parse_public_key(mbedtls_pk_context *ctx, const unsigned char *key, size_t keylen); #if defined(MBEDTLS_FS_IO) /** \ingroup pk_module */ /** * \brief Load and parse a private key * * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto * subsystem must have been initialized by calling * psa_crypto_init() before calling this function. * * \param ctx The PK context to fill. It must have been initialized * but not set up. * \param path filename to read the private key from * \param password Optional password to decrypt the file. * Pass \c NULL if expecting a non-encrypted key. * Pass a null-terminated string if expecting an encrypted * key; a non-encrypted key will also be accepted. * The empty password is not supported. * \param f_rng RNG function, must not be \c NULL. Used for blinding. * \param p_rng RNG parameter * * \note On entry, ctx must be empty, either freshly initialised * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If you need a * specific key type, check the result with mbedtls_pk_can_do(). * * \note The key is also checked for correctness. * * \return 0 if successful, or a specific PK or PEM error code */ int mbedtls_pk_parse_keyfile(mbedtls_pk_context *ctx, const char *path, const char *password, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng); /** \ingroup pk_module */ /** * \brief Load and parse a public key * * \param ctx The PK context to fill. It must have been initialized * but not set up. * \param path filename to read the public key from * * \note On entry, ctx must be empty, either freshly initialised * with mbedtls_pk_init() or reset with mbedtls_pk_free(). If * you need a specific key type, check the result with * mbedtls_pk_can_do(). * * \note The key is also checked for correctness. * * \return 0 if successful, or a specific PK or PEM error code */ int mbedtls_pk_parse_public_keyfile(mbedtls_pk_context *ctx, const char *path); #endif /* MBEDTLS_FS_IO */ #endif /* MBEDTLS_PK_PARSE_C */ #if defined(MBEDTLS_PK_WRITE_C) /** * \brief Write a private key to a PKCS#1 or SEC1 DER structure * Note: data is written at the end of the buffer! Use the * return value to determine where you should start * using the buffer * * \param ctx PK context which must contain a valid private key. * \param buf buffer to write to * \param size size of the buffer * * \return length of data written if successful, or a specific * error code */ int mbedtls_pk_write_key_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size); /** * \brief Write a public key to a SubjectPublicKeyInfo DER structure * Note: data is written at the end of the buffer! Use the * return value to determine where you should start * using the buffer * * \param ctx PK context which must contain a valid public or private key. * \param buf buffer to write to * \param size size of the buffer * * \return length of data written if successful, or a specific * error code */ int mbedtls_pk_write_pubkey_der(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size); #if defined(MBEDTLS_PEM_WRITE_C) /** * \brief Write a public key to a PEM string * * \param ctx PK context which must contain a valid public or private key. * \param buf Buffer to write to. The output includes a * terminating null byte. * \param size Size of the buffer in bytes. * * \return 0 if successful, or a specific error code */ int mbedtls_pk_write_pubkey_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size); /** * \brief Write a private key to a PKCS#1 or SEC1 PEM string * * \param ctx PK context which must contain a valid private key. * \param buf Buffer to write to. The output includes a * terminating null byte. * \param size Size of the buffer in bytes. * * \return 0 if successful, or a specific error code */ int mbedtls_pk_write_key_pem(const mbedtls_pk_context *ctx, unsigned char *buf, size_t size); #endif /* MBEDTLS_PEM_WRITE_C */ #endif /* MBEDTLS_PK_WRITE_C */ /* * WARNING: Low-level functions. You probably do not want to use these unless * you are certain you do ;) */ #if defined(MBEDTLS_PK_PARSE_C) /** * \brief Parse a SubjectPublicKeyInfo DER structure * * \param p the position in the ASN.1 data * \param end end of the buffer * \param pk The PK context to fill. It must have been initialized * but not set up. * * \return 0 if successful, or a specific PK error code */ int mbedtls_pk_parse_subpubkey(unsigned char **p, const unsigned char *end, mbedtls_pk_context *pk); #endif /* MBEDTLS_PK_PARSE_C */ #if defined(MBEDTLS_PK_WRITE_C) /** * \brief Write a subjectPublicKey to ASN.1 data * Note: function works backwards in data buffer * * \param p reference to current position pointer * \param start start of the buffer (for bounds-checking) * \param key PK context which must contain a valid public or private key. * * \return the length written or a negative error code */ int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start, const mbedtls_pk_context *key); #endif /* MBEDTLS_PK_WRITE_C */ #ifdef __cplusplus } #endif #endif /* MBEDTLS_PK_H */