diff --git a/include/hardware/keymaster_common.h b/include/hardware/keymaster_common.h
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+++ b/include/hardware/keymaster_common.h
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+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_KEYMASTER_COMMON_H
+#define ANDROID_HARDWARE_KEYMASTER_COMMON_H
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+#include <hardware/hardware.h>
+
+__BEGIN_DECLS
+
+/**
+ * The id of this module
+ */
+#define KEYSTORE_HARDWARE_MODULE_ID "keystore"
+
+#define KEYSTORE_KEYMASTER "keymaster"
+
+
+/**
+ * Settings for "module_api_version" and "hal_api_version"
+ * fields in the keymaster_module initialization.
+ */
+
+/**
+ * Keymaster 0.X module version provide the same APIs, but later versions add more options
+ * for algorithms and flags.
+ */
+#define KEYMASTER_MODULE_API_VERSION_0_2 HARDWARE_MODULE_API_VERSION(0, 2)
+#define KEYMASTER_DEVICE_API_VERSION_0_2 HARDWARE_DEVICE_API_VERSION(0, 2)
+
+#define KEYMASTER_MODULE_API_VERSION_0_3 HARDWARE_MODULE_API_VERSION(0, 3)
+#define KEYMASTER_DEVICE_API_VERSION_0_3 HARDWARE_DEVICE_API_VERSION(0, 3)
+
+/**
+ * Keymaster 1.0 module version provides a completely different API, incompatible with 0.X.
+ */
+#define KEYMASTER_MODULE_API_VERSION_1_0 HARDWARE_MODULE_API_VERSION(1, 0)
+#define KEYMASTER_DEVICE_API_VERSION_1_0 HARDWARE_DEVICE_API_VERSION(1, 0)
+
+struct keystore_module {
+    /**
+     * Common methods of the keystore module.  This *must* be the first member of keystore_module as
+     * users of this structure will cast a hw_module_t to keystore_module pointer in contexts where
+     * it's known the hw_module_t references a keystore_module.
+     */
+    hw_module_t common;
+
+    /* There are no keystore module methods other than the common ones. */
+};
+
+/**
+ * Flags for keymaster0_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,
+};
+
+/**
+ * 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_algorithm_t;
+
+/**
+ * Type of padding used for RSA operations.
+ */
+typedef enum {
+    PADDING_NONE,
+} keymaster_rsa_padding_t;
+
+
+typedef struct {
+    keymaster_digest_algorithm_t digest_type;
+} keymaster_dsa_sign_params_t;
+
+typedef struct {
+    keymaster_digest_algorithm_t digest_type;
+} keymaster_ec_sign_params_t;
+
+typedef struct {
+    keymaster_digest_algorithm_t digest_type;
+    keymaster_rsa_padding_t padding_type;
+} keymaster_rsa_sign_params_t;
+
+__END_DECLS
+
+#endif  // ANDROID_HARDWARE_KEYMASTER_COMMON_H