diff --git a/include/hardware/keymaster.h b/include/hardware/keymaster.h
index 8c5ff14..a6200a5 100644
--- a/include/hardware/keymaster.h
+++ b/include/hardware/keymaster.h
@@ -22,6 +22,7 @@
 #include <sys/types.h>
 
 #include <hardware/hardware.h>
+#include <hardware/keymaster_defs.h>
 
 __BEGIN_DECLS
 
@@ -36,51 +37,19 @@
  * Settings for "module_api_version" and "hal_api_version"
  * fields in the keymaster_module initialization.
  */
-#define KEYMASTER_HEADER_VERSION 3
+#define KEYMASTER_HEADER_VERSION 4
 
-#define KEYMASTER_MODULE_API_VERSION_0_2  HARDWARE_MODULE_API_VERSION(0, 2)
-#define KEYMASTER_DEVICE_API_VERSION_0_2  HARDWARE_DEVICE_API_VERSION_2(0, 2, KEYMASTER_HEADER_VERSION)
+#define KEYMASTER_MODULE_API_VERSION_0_2 HARDWARE_MODULE_API_VERSION(0, 2)
+#define KEYMASTER_DEVICE_API_VERSION_0_2 \
+    HARDWARE_DEVICE_API_VERSION_2(0, 2, KEYMASTER_HEADER_VERSION)
 
-#define KEYMASTER_MODULE_API_VERSION_0_3  HARDWARE_MODULE_API_VERSION(0, 3)
-#define KEYMASTER_DEVICE_API_VERSION_0_3  HARDWARE_DEVICE_API_VERSION_2(0, 3, KEYMASTER_HEADER_VERSION)
+#define KEYMASTER_MODULE_API_VERSION_0_3 HARDWARE_MODULE_API_VERSION(0, 3)
+#define KEYMASTER_DEVICE_API_VERSION_0_3 \
+    HARDWARE_DEVICE_API_VERSION_2(0, 3, KEYMASTER_HEADER_VERSION)
 
-/**
- * Flags for keymaster_device::flags
- */
-enum {
-    /*
-     * Indicates this keymaster implementation does not have hardware that
-     * keeps private keys out of user space.
-     *
-     * This should not be implemented on anything other than the default
-     * implementation.
-     */
-    KEYMASTER_SOFTWARE_ONLY = 1 << 0,
-
-    /*
-     * This indicates that the key blobs returned via all the primitives
-     * are sufficient to operate on their own without the trusted OS
-     * querying userspace to retrieve some other data. Key blobs of
-     * this type are normally returned encrypted with a
-     * Key Encryption Key (KEK).
-     *
-     * This is currently used by "vold" to know whether the whole disk
-     * encryption secret can be unwrapped without having some external
-     * service started up beforehand since the "/data" partition will
-     * be unavailable at that point.
-     */
-    KEYMASTER_BLOBS_ARE_STANDALONE = 1 << 1,
-
-    /*
-     * Indicates that the keymaster module supports DSA keys.
-     */
-    KEYMASTER_SUPPORTS_DSA = 1 << 2,
-
-    /*
-     * Indicates that the keymaster module supports EC keys.
-     */
-    KEYMASTER_SUPPORTS_EC = 1 << 3,
-};
+#define KEYMASTER_MODULE_API_VERSION_0_4 HARDWARE_MODULE_API_VERSION(0, 4)
+#define KEYMASTER_DEVICE_API_VERSION_0_4 \
+    HARDWARE_DEVICE_API_VERSION_2(0, 4, KEYMASTER_HEADER_VERSION)
 
 struct keystore_module {
     /**
@@ -93,82 +62,6 @@
 };
 
 /**
- * Asymmetric key pair types.
- */
-typedef enum {
-    TYPE_RSA = 1,
-    TYPE_DSA = 2,
-    TYPE_EC = 3,
-} keymaster_keypair_t;
-
-/**
- * Parameters needed to generate an RSA key.
- */
-typedef struct {
-    uint32_t modulus_size;
-    uint64_t public_exponent;
-} keymaster_rsa_keygen_params_t;
-
-/**
- * Parameters needed to generate a DSA key.
- */
-typedef struct {
-    uint32_t key_size;
-    uint32_t generator_len;
-    uint32_t prime_p_len;
-    uint32_t prime_q_len;
-    const uint8_t* generator;
-    const uint8_t* prime_p;
-    const uint8_t* prime_q;
-} keymaster_dsa_keygen_params_t;
-
-/**
- * Parameters needed to generate an EC key.
- *
- * Field size is the only parameter in version 2. The sizes correspond to these required curves:
- *
- * 192 = NIST P-192
- * 224 = NIST P-224
- * 256 = NIST P-256
- * 384 = NIST P-384
- * 521 = NIST P-521
- *
- * The parameters for these curves are available at: http://www.nsa.gov/ia/_files/nist-routines.pdf
- * in Chapter 4.
- */
-typedef struct {
-    uint32_t field_size;
-} keymaster_ec_keygen_params_t;
-
-/**
- * Digest type.
- */
-typedef enum {
-    DIGEST_NONE,
-} keymaster_digest_t;
-
-/**
- * Type of padding used for RSA operations.
- */
-typedef enum {
-    PADDING_NONE,
-} keymaster_rsa_padding_t;
-
-
-typedef struct {
-    keymaster_digest_t digest_type;
-} keymaster_dsa_sign_params_t;
-
-typedef struct {
-    keymaster_digest_t digest_type;
-} keymaster_ec_sign_params_t;
-
-typedef struct {
-    keymaster_digest_t digest_type;
-    keymaster_rsa_padding_t padding_type;
-} keymaster_rsa_sign_params_t;
-
-/**
  * The parameters that can be set for a given keymaster implementation.
  */
 struct keymaster_device {
@@ -194,52 +87,49 @@
     void* context;
 
     /**
-     * Generates a public and private key. The key-blob returned is opaque
-     * and must subsequently provided for signing and verification.
+     * \deprecated Generates a public and private key. The key-blob returned is opaque and must
+     * subsequently provided for signing and verification.
      *
      * Returns: 0 on success or an error code less than 0.
      */
-    int (*generate_keypair)(const struct keymaster_device* dev,
-            const keymaster_keypair_t key_type, const void* key_params,
-            uint8_t** key_blob, size_t* key_blob_length);
+    int (*generate_keypair)(const struct keymaster_device* dev, const keymaster_keypair_t key_type,
+                            const void* key_params, uint8_t** key_blob, size_t* key_blob_length);
 
     /**
-     * Imports a public and private key pair. The imported keys will be in
-     * PKCS#8 format with DER encoding (Java standard). The key-blob
-     * returned is opaque and will be subsequently provided for signing
-     * and verification.
+     * \deprecated Imports a public and private key pair. The imported keys will be in PKCS#8 format
+     * with DER encoding (Java standard). The key-blob returned is opaque and will be subsequently
+     * provided for signing and verification.
      *
      * Returns: 0 on success or an error code less than 0.
      */
-    int (*import_keypair)(const struct keymaster_device* dev,
-            const uint8_t* key, const size_t key_length,
-            uint8_t** key_blob, size_t* key_blob_length);
+    int (*import_keypair)(const struct keymaster_device* dev, const uint8_t* key,
+                          const size_t key_length, uint8_t** key_blob, size_t* key_blob_length);
 
     /**
-     * Gets the public key part of a key pair. The public key must be in
-     * X.509 format (Java standard) encoded byte array.
+     * \deprecated Gets the public key part of a key pair. The public key must be in X.509 format
+     * (Java standard) encoded byte array.
      *
-     * Returns: 0 on success or an error code less than 0.
-     * On error, x509_data should not be allocated.
+     * Returns: 0 on success or an error code less than 0.  On error, x509_data
+     * should not be allocated.
      */
-    int (*get_keypair_public)(const struct keymaster_device* dev,
-            const uint8_t* key_blob, const size_t key_blob_length,
-            uint8_t** x509_data, size_t* x509_data_length);
+    int (*get_keypair_public)(const struct keymaster_device* dev, const uint8_t* key_blob,
+                              const size_t key_blob_length, uint8_t** x509_data,
+                              size_t* x509_data_length);
 
     /**
-     * Deletes the key pair associated with the key blob.
+     * \deprecated Deletes the key pair associated with the key blob.
      *
      * This function is optional and should be set to NULL if it is not
      * implemented.
      *
      * Returns 0 on success or an error code less than 0.
      */
-    int (*delete_keypair)(const struct keymaster_device* dev,
-            const uint8_t* key_blob, const size_t key_blob_length);
+    int (*delete_keypair)(const struct keymaster_device* dev, const uint8_t* key_blob,
+                          const size_t key_blob_length);
 
     /**
-     * Deletes all keys in the hardware keystore. Used when keystore is
-     * reset completely.
+     * \deprecated Deletes all keys in the hardware keystore. Used when keystore is reset
+     * completely.
      *
      * This function is optional and should be set to NULL if it is not
      * implemented.
@@ -249,45 +139,515 @@
     int (*delete_all)(const struct keymaster_device* dev);
 
     /**
-     * Signs data using a key-blob generated before. This can use either
-     * an asymmetric key or a secret key.
+     * \deprecated Signs data using a key-blob generated before. This can use either an asymmetric
+     * key or a secret key.
      *
      * Returns: 0 on success or an error code less than 0.
      */
-    int (*sign_data)(const struct keymaster_device* dev,
-            const void* signing_params,
-            const uint8_t* key_blob, const size_t key_blob_length,
-            const uint8_t* data, const size_t data_length,
-            uint8_t** signed_data, size_t* signed_data_length);
+    int (*sign_data)(const struct keymaster_device* dev, const void* signing_params,
+                     const uint8_t* key_blob, const size_t key_blob_length, const uint8_t* data,
+                     const size_t data_length, uint8_t** signed_data, size_t* signed_data_length);
 
     /**
-     * Verifies data signed with a key-blob. This can use either
-     * an asymmetric key or a secret key.
+     * \deprecated Verifies data signed with a key-blob. This can use either an asymmetric key or a
+     * secret key.
      *
      * Returns: 0 on successful verification or an error code less than 0.
      */
-    int (*verify_data)(const struct keymaster_device* dev,
-            const void* signing_params,
-            const uint8_t* key_blob, const size_t key_blob_length,
-            const uint8_t* signed_data, const size_t signed_data_length,
-            const uint8_t* signature, const size_t signature_length);
+    int (*verify_data)(const struct keymaster_device* dev, const void* signing_params,
+                       const uint8_t* key_blob, const size_t key_blob_length,
+                       const uint8_t* signed_data, const size_t signed_data_length,
+                       const uint8_t* signature, const size_t signature_length);
+
+    /**
+     * Gets algorithms supported.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[out] algorithms Array of algorithms supported.  The caller takes ownership of the
+     * array and must free() it.
+     *
+     * \param[out] algorithms_length Length of \p algorithms.
+     */
+    keymaster_error_t (*get_supported_algorithms)(const struct keymaster_device* dev,
+                                                  keymaster_algorithm_t** algorithms,
+                                                  size_t* algorithms_length);
+
+    /**
+     * Gets the block modes supported for the specified algorithm.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] algorithm The algorithm for which supported modes will be returned.
+     *
+     * \param[out] modes Array of modes supported.  The caller takes ownership of the array and must
+     * free() it.
+     *
+     * \param[out] modes_length Length of \p modes.
+     */
+    keymaster_error_t (*get_supported_block_modes)(const struct keymaster_device* dev,
+                                                   keymaster_algorithm_t algorithm,
+                                                   keymaster_purpose_t purpose,
+                                                   keymaster_block_mode_t** modes,
+                                                   size_t* modes_length);
+
+    /**
+     * Gets the padding modes supported for the specified algorithm.  Caller assumes ownership of
+     * the allocated array.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] algorithm The algorithm for which supported padding modes will be returned.
+     *
+     * \param[out] modes Array of padding modes supported.  The caller takes ownership of the array
+     * and must free() it.
+     *
+     * \param[out] modes_length Length of \p modes.
+     */
+    keymaster_error_t (*get_supported_padding_modes)(const struct keymaster_device* dev,
+                                                     keymaster_algorithm_t algorithm,
+                                                     keymaster_purpose_t purpose,
+                                                     keymaster_padding_t** modes,
+                                                     size_t* modes_length);
+
+    /**
+     * Gets the digests supported for the specified algorithm.  Caller assumes ownership of the
+     * allocated array.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] algorithm The algorithm for which supported digests will be returned.
+     *
+     * \param[out] digests Array of digests supported.  The caller takes ownership of the array and
+     * must free() it.
+     *
+     * \param[out] digests_length Length of \p digests.
+     */
+    keymaster_error_t (*get_supported_digests)(const struct keymaster_device* dev,
+                                               keymaster_algorithm_t algorithm,
+                                               keymaster_purpose_t purpose,
+                                               keymaster_digest_t** digests,
+                                               size_t* digests_length);
+
+    /**
+     * Gets the key import formats supported for keys of the specified algorithm.  Caller assumes
+     * ownership of the allocated array.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] algorithm The algorithm for which supported formats will be returned.
+     *
+     * \param[out] formats Array of formats supported.  The caller takes ownership of the array and
+     * must free() it.
+     *
+     * \param[out] formats_length Length of \p formats.
+     */
+    keymaster_error_t (*get_supported_import_formats)(const struct keymaster_device* dev,
+                                                      keymaster_algorithm_t algorithm,
+                                                      keymaster_key_format_t** formats,
+                                                      size_t* formats_length);
+
+    /**
+     * Gets the key export formats supported for keys of the specified algorithm.  Caller assumes
+     * ownership of the allocated array.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] algorithm The algorithm for which supported formats will be returned.
+     *
+     * \param[out] formats Array of formats supported.  The caller takes ownership of the array and
+     * must free() it.
+     *
+     * \param[out] formats_length Length of \p formats.
+     */
+    keymaster_error_t (*get_supported_export_formats)(const struct keymaster_device* dev,
+                                                      keymaster_algorithm_t algorithm,
+                                                      keymaster_key_format_t** formats,
+                                                      size_t* formats_length);
+
+    /**
+     * Adds entropy to the RNG used by keymaster.  Entropy added through this method is guaranteed
+     * not to be the only source of entropy used, and the mixing function is required to be secure,
+     * in the sense that if the RNG is seeded (from any source) with any data the attacker cannot
+     * predict (or control), then the RNG output is indistinguishable from random.  Thus, if the
+     * entropy from any source is good, the output will be good.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] data Random data to be mixed in.
+     *
+     * \param[in] data_length Length of \p data.
+     */
+    keymaster_error_t (*add_rng_entropy)(const struct keymaster_device* dev, uint8_t* data,
+                                         size_t data_length);
+
+    /**
+     * Generates a key, or key pair, returning a key blob and/or a description of the key.
+     *
+     * Key generation parameters are defined as keymaster tag/value pairs, provided in \p params.
+     * See keymaster_tag_t for the full list.  Some values that are always required for generation
+     * of useful keys are:
+     *
+     * - KM_TAG_ALGORITHM;
+     * - KM_TAG_PURPOSE;
+     * - KM_TAG_USER_ID or KM_TAG_ALL_USERS;
+     * - KM_TAG_USER_AUTH_ID or KM_TAG_NO_AUTH_REQUIRED;
+     * - KM_TAG_APPLICATION_ID or KM_TAG_ALL_APPLICATIONS; and
+     * - KM_TAG_ORIGINATION_EXPIRE_DATETIME
+     *
+     * KM_TAG_AUTH_TIMEOUT should generally be specified unless KM_TAG_NO_AUTH_REQUIRED is present,
+     * or the user will have to authenticate for every use.
+     *
+     * KM_TAG_BLOCK_MODE, KM_TAG_PADDING, KM_TAG_MAC_LENGTH and KM_TAG_DIGEST must be specified for
+     * algorithms that require them.
+     *
+     * The following tags will take default values if unspecified:
+     *
+     * - KM_TAG_KEY_SIZE defaults to a recommended key size for the  specified algorithm.
+     *
+     * - KM_TAG_USAGE_EXPIRE_DATETIME defaults to the value of KM_TAG_ORIGINATION_EXPIRE_DATETIME.
+     *
+     * - KM_TAG_ACTIVE_DATETIME will default to the value of KM_TAG_CREATION_DATETIME
+     *
+     * - KM_TAG_ROOT_OF_TRUST will default to the current root of trust.
+     *
+     * - KM_TAG_{RSA|DSA|DH}_* will default to values appropriate for the specified key size.
+     *
+     * The following tags may not be specified; their values will be provided by the implementation.
+     *
+     * - KM_TAG_ORIGIN,
+     *
+     * - KM_TAG_ROLLBACK_RESISTANT,
+     *
+     * - KM_TAG_CREATION_DATETIME,
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] params Array of key generation parameters.
+     *
+     * \param[in] params_count Length of \p params.
+     *
+     * \param[out] key_blob returns the generated key. If \p key_blob is NULL, no key is generated,
+     * but the characteristics of the key that would be generated are returned.  The caller assumes
+     * ownership key_blob->key_material and must free() it.
+     *
+     * \param[out] characteristics returns the characteristics of the key that was, or would be,
+     * generated, if non-NULL.  The caller assumes ownership, and the object must be freed with
+     * keymaster_free_characteristics().  Note that KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and
+     * KM_TAG_APPLICATION_DATA are never returned.
+     */
+    keymaster_error_t (*generate_key)(const struct keymaster_device* dev,
+                                      const keymaster_key_param_t* params, size_t params_count,
+                                      keymaster_key_blob_t* key_blob,
+                                      keymaster_key_characteristics_t** characteristics);
+
+    /**
+     * Returns the characteristics of the specified key, or NULL if the key_blob is invalid
+     * (implementations must fully validate the integrity of the key).  client_id and app_data must
+     * be the ID and data provided when the key was generated or imported.  Those values are not
+     * included in the returned characteristics.  Caller assumes ownership of the allocated
+     * characteristics object, which must be deallocated with keymaster_free_characteristics().
+     *
+     * Note that KM_TAG_ROOT_OF_TRUST, KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA are never
+     * returned.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] key_blob The key to retreive characteristics from.
+     *
+     * \param[in] client_id The client ID data, or NULL if none associated.
+     *
+     * \param[in] app_id The app data, or NULL if none associated.
+     *
+     * \param[out] characteristics The key characteristics.
+     */
+    keymaster_error_t (*get_key_characteristics)(const struct keymaster_device* dev,
+                                                 const keymaster_key_blob_t* key_blob,
+                                                 const keymaster_blob_t* client_id,
+                                                 const keymaster_blob_t* app_data,
+                                                 keymaster_key_characteristics_t** characteristics);
+
+    /**
+     * Change a key's authorizations.
+     *
+     * Update the authorizations associated with key_blob to the list specified in new_params, which
+     * must contain the complete set of authorizations desired (hw_enforced and sw_enforced).  Tags
+     * will be added, removed and/or updated only if the appropriate KM_TAG_RESCOPING_ADD and
+     * KM_TAG_RESCOPING_DEL tags exist in the key's authorizations, otherwise
+     * KM_ERROR_INVALID_RESCOPING will be returned and no changes will be made.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] new_params The new authorization list to be associated with the key.
+     *
+     * \param[in] new_params_count The number of entries in \p new_params.
+     *
+     * \param[in] key_blob The key to update.
+     *
+     * \param[in] client_id The client ID associated with the key, or NULL if none is associated.
+     *
+     * \param[in] app_data The application data associated with the key, or NULL if none is
+     * associated.
+     *
+     * \param[out] rescoped_key_blob The key blob with the updated authorizations, if successful.
+     * The caller assumes ownership of rescoped_key_blob->key_material and must free() it.
+     *
+     * \param[out] characteristics If not null will contain the new key authorizations, divided into
+     * hw_enforced and sw_enforced lists.  The caller takes ownership and must call
+     * keymaster_free_characteristics() to free.
+     */
+    keymaster_error_t (*rescope)(const struct keymaster_device* dev,
+                                 const keymaster_key_param_t* new_params, size_t new_params_count,
+                                 const keymaster_key_blob_t* key_blob,
+                                 const keymaster_blob_t* client_id,
+                                 const keymaster_blob_t* app_data,
+                                 const keymaster_key_blob_t* rescoped_key_blob,
+                                 keymaster_key_characteristics_t** characteristics);
+
+    /**
+     * Imports a key, or key pair, returning a key blob and/or a description of the key.
+     *
+     * Most key import parameters are defined as keymaster tag/value pairs, provided in "params".
+     * See keymaster_tag_t for the full list.  Some values that are always required for import of
+     * useful keys are:
+     *
+     * - KM_TAG_PURPOSE;
+     *
+     * - KM_TAG_USER_ID
+     *
+     * - KM_TAG_USER_AUTH_ID;
+     *
+     * - KM_TAG_APPLICATION_ID or KM_TAG_ALL_APPLICATIONS;
+     *
+     * - KM_TAG_PRIVKEY_EXPIRE_DATETIME.
+     *
+     * KM_TAG_AUTH_TIMEOUT should generally be specified. If unspecified, the user will have to
+     * authenticate for every use, unless KM_TAG_USER_AUTH_ID is set to
+     * KM_NO_AUTHENTICATION_REQUIRED.
+     *
+     * The following tags will take default values if unspecified:
+     *
+     * - KM_TAG_PUBKEY_EXPIRE_DATETIME will default to the value for KM_TAG_PRIVKEY_EXPIRE_DATETIME.
+     *
+     * - KM_TAG_ACTIVE_DATETIME will default to the value of KM_TAG_CREATION_DATETIME
+     *
+     * - KM_TAG_ROOT_OF_TRUST will default to the current root of trust.
+     *
+     * The following tags may not be specified; their values will be provided by the implementation.
+     *
+     * - KM_TAG_ORIGIN,
+     *
+     * - KM_TAG_ROLLBACK_RESISTANT,
+     *
+     * - KM_TAG_CREATION_DATETIME,
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] params Parameters defining the imported key.
+     *
+     * \param[in] params_count The number of entries in \p params.
+     *
+     * \param[in] key_format specifies the format of the key data in key_data.
+     *
+     * \param[out] key_blob Used to return the opaque key blob.  Must be non-NULL.  The caller
+     * assumes ownership of the contained key_material.
+     *
+     * \param[out] characteristics Used to return the characteristics of the imported key.  May be
+     * NULL, in which case no characteristics will be returned.  If non-NULL, the caller assumes
+     * ownership and must deallocate with keymaster_free_characteristics().
+     */
+    keymaster_error_t (*import_key)(const struct keymaster_device* dev,
+                                    const keymaster_key_param_t* params, size_t params_count,
+                                    keymaster_key_format_t key_format, const uint8_t* key_data,
+                                    size_t key_data_length, keymaster_key_blob_t* key_blob,
+                                    keymaster_key_characteristics_t** characteristics);
+
+    /**
+     * Exports a public key, returning a byte array in the specified format.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] export_format The format to be used for exporting the key.
+     *
+     * \param[in] key_to_export The key to export.
+     *
+     * \param[out] export_data The exported key material.  The caller assumes ownership.
+     *
+     * \param[out] export_data_length The length of \p export_data.
+     */
+    keymaster_error_t (*export_key)(const struct keymaster_device* dev,
+                                    keymaster_key_format_t export_format,
+                                    const keymaster_key_blob_t* key_to_export,
+                                    const keymaster_blob_t* client_id,
+                                    const keymaster_blob_t* app_data, uint8_t** export_data,
+                                    size_t* export_data_length);
+
+    /**
+     * Deletes the key, or key pair, associated with the key blob.  After calling this function it
+     * will be impossible to use the key for any other operations (though rescoped versions may
+     * exist, and if so will be usable).  May be applied to keys from foreign roots of trust (keys
+     * not usable under the current root of trust).
+     *
+     * This function is optional and should be set to NULL if it is not implemented.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] key The key to be deleted.
+     */
+    keymaster_error_t (*delete_key)(const struct keymaster_device* dev,
+                                    const keymaster_key_blob_t* key);
+
+    /**
+     * Deletes all keys in the hardware keystore. Used when keystore is reset completely.  After
+     * calling this function it will be impossible to use any previously generated or imported key
+     * blobs for any operations.
+     *
+     * This function is optional and should be set to NULL if it is not implemented.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * Returns 0 on success or an error code less than 0.
+     */
+    int (*delete_all_keys)(const struct keymaster_device* dev);
+
+    /**
+     * Begins a cryptographic operation using the specified key.  If all is well, begin() will
+     * return KM_ERROR_OK and create an operation handle which must be passed to subsequent calls to
+     * update(), finish() or abort().
+     *
+     * It is critical that each call to begin() be paired with a subsequent call to finish() or
+     * abort(), to allow the keymaster implementation to clean up any internal operation state.
+     * Failure to do this will leak internal state space or other internal resources and will
+     * eventually cause begin() to return KM_ERROR_TOO_MANY_OPERATIONS when it runs out of space for
+     * operations.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] purpose The purpose of the operation, one of KM_PURPOSE_ENCRYPT,
+     * KM_PURPOSE_DECRYPT, KM_PURPOSE_SIGN or KM_PURPOSE_VERIFY. Note that for AEAD modes,
+     * encryption and decryption imply signing and verification, respectively.
+     *
+     * \param[in] key The key to be used for the operation. \p key must have a purpose compatible
+     * with \p purpose and all of its usage requirements must be satisfied, or begin() will return
+     * an appropriate error code.
+     *
+     * \param[in] params Additional parameters for the operation.  This is typically used to provide
+     * client ID information, with tags KM_TAG_APPLICATION_ID and KM_TAG_APPLICATION_DATA.  If the
+     * client information associated with the key is not provided, begin() will fail and return
+     * KM_ERROR_INVALID_KEY_BLOB.  Less commonly, \params can be used to provide AEAD additional
+     * data and chunk size with KM_TAG_ADDITIONAL_DATA or KM_TAG_CHUNK_SIZE respectively.
+     *
+     * \param[in] params_count The number of entries in \p params.
+     *
+     * \param[out] out_params Array of output parameters.  The caller takes ownership of the output
+     * parametes array and must free it.  out_params may be set to NULL if no output parameters are
+     * expected.  If NULL, and output paramaters are generated, begin() will return
+     * KM_ERROR_OUTPUT_PARAMETER_NULL.
+     *
+     * \param[out] out_params_count The length of out_params.
+     *
+     * \param[out] operation_handle The newly-created operation handle which must be passed to
+     * update(), finish() or abort().
+     */
+    keymaster_error_t (*begin)(const struct keymaster_device* dev, keymaster_purpose_t purpose,
+                               const keymaster_key_blob_t* key, const keymaster_key_param_t* params,
+                               size_t params_count, keymaster_key_param_t** out_params,
+                               size_t* out_params_count,
+                               keymaster_operation_handle_t* operation_handle);
+
+    /**
+     * Get an estimate of the output that will be generated by calling update() with the specified
+     * number of input bytes, followed by finish().  The estimate may not be exact, but is
+     * guaranteed not to be smaller than sum of the output lengths from update() and finish().  The
+     * estimate takes into account input data already provided.
+     *
+     * \param[in] input_length The number of additional input bytes to be processed.
+     *
+     * \param[out] output_estimate The length of the output that will be produced.
+     */
+    keymaster_error_t (*get_output_size)(size_t input_length, size_t* output_estimate);
+
+    /**
+     * Provides data to, and possibly receives output from, an ongoing cryptographic operation begun
+     * with begin().
+     *
+     * If operation_handle is invalid, update() will return KM_ERROR_INVALID_OPERATION_HANDLE.
+     *
+     * Not all of the data provided in the data buffer may be consumed.  update() will return the
+     * amount consumed in *data_consumed.  The caller should provide the unconsumed data in a
+     * subsequent call.
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] operation_handle The operation handle returned by begin().
+     *
+     * \param[in] input Data to be processed, per the parameters established in the call to begin().
+     * Note that update() may or may not consume all of the data provided.  See \p data_consumed.
+     *
+     * \param[in] input_length Length of \p input.
+     *
+     * \param[out] input_consumed Amount of data that was consumed by update().  If this is less
+     * than the amount provided, the caller should provide the remainder in a subsequent call to
+     * update().
+     *
+     * \param[out] output The output data, if any.  The caller assumes ownership of the allocated
+     * buffer.  If output is NULL then NO input data is consumed and no output is produced, but
+     * *output_length is set to an estimate of the size that would have been produced by this
+     * update() and a subsequent finish().
+     *
+     * \param[out] output_length The length of the output buffer.
+     *
+     * Note that update() may not provide any output, in which case *output_length will be zero, and
+     * *output may be either NULL or zero-length (so the caller should always free() it).
+     */
+    keymaster_error_t (*update)(const struct keymaster_device* dev,
+                                keymaster_operation_handle_t operation_handle, const uint8_t* input,
+                                size_t input_length, size_t* input_consumed, uint8_t** output,
+                                size_t* output_length);
+
+    /**
+     * Finalizes a cryptographic operation begun with begin() and invalidates operation_handle
+     * (except in the insufficient buffer case, detailed below).
+     *
+     * \param[in] dev The keymaster device structure.
+     *
+     * \param[in] operation_handle The operation handle returned by begin().  This handle will be
+     * invalidated.
+     *
+     * \param[in] signature The signature to be verified if the purpose specified in the begin()
+     * call was KM_PURPOSE_VERIFY.
+     *
+     * \param[in] signature_length The length of \p signature.
+     *
+     * \param[out] output The output data, if any.  The caller assumes ownership of the allocated
+     * buffer.
+     *
+     * \param[out] output_length The length of the output buffer.
+     *
+     * If the operation being finished is a signature verification or an AEAD-mode decryption and
+     * verification fails then finish() will return KM_ERROR_VERIFICATION_FAILED.
+     */
+    keymaster_error_t (*finish)(const struct keymaster_device* dev,
+                                keymaster_operation_handle_t operation_handle,
+                                const uint8_t* signature, size_t signature_length, uint8_t** output,
+                                size_t* output_length);
+
+    /**
+     * Aborts a cryptographic operation begun with begin(), freeing all internal resources and
+     * invalidating operation_handle.
+     */
+    keymaster_error_t (*abort)(const struct keymaster_device* dev,
+                               keymaster_operation_handle_t operation_handle);
 };
 typedef struct keymaster_device keymaster_device_t;
 
-
 /* Convenience API for opening and closing keymaster devices */
 
-static inline int keymaster_open(const struct hw_module_t* module,
-        keymaster_device_t** device)
-{
-    int rc = module->methods->open(module, KEYSTORE_KEYMASTER,
-            (struct hw_device_t**) device);
-
-    return rc;
+static inline int keymaster_open(const struct hw_module_t* module, keymaster_device_t** device) {
+    return module->methods->open(module, KEYSTORE_KEYMASTER, (struct hw_device_t**)device);
 }
 
-static inline int keymaster_close(keymaster_device_t* device)
-{
+static inline int keymaster_close(keymaster_device_t* device) {
     return device->common.close(&device->common);
 }