update api reference doc for cryptographic

Signed-off-by: wanghouqi <houqix.wang@intel.com>

docs/API_Reference.md

@@ -68,8 +68,11 @@ Create a customer master key(CMK) for the user, which can be a symmetric or an a
 
    | Name | Type | Reference Value | Description |
    |:-----------|:-----------|:-----------|:-----------|
-   | Keyspec | String   |  EH_AES_GCM_128 |The keyspec the user want to create, it can be the following one: <br>EH_AES_GCM_128 <br>EH_AES_GCM_256<br>EH_RSA_3072<br>EH_RSA_4096<br>EH_EC_P256<br>EH_EC_P512<br>EH_EC_SM2<br>EH_SM4<br><br>**Notes:**  currently on support the keyspec(EH_AES_GCM_128 and EH_RSA_3072), for others will support later.|
-   | origin | String | EH_INTERNAL_KEY | The source about the cmk comes from, it can be:<br> EH_INTERNAL_KEY (generated from the eHSM inside)<br>EXTERNAL_KEY (generated by the customer and want to import into the eHSM)<br><br>**Notes:** currently it only support the type of EH_INTERNAL_KEY. |
+   | Keyspec | String   |  EH_AES_GCM_128 |The keyspec the user want to create, it can be the following one: <br>EH_AES_GCM_128<br>EH_AES_GCM_192<br>EH_AES_GCM_256<br>EH_RSA_2048<br>EH_RSA_3072<br>EH_RSA_4096<br>EH_EC_P224<br>EH_EC_P256<br>EH_EC_P384<br>EH_EC_P521<br>EH_SM2<br>EH_SM4_CTR<br>EH_SM4_CBC<br>EH_HMAC<br><br>**Notes:**  EH_HMAC is not supported at present, and will be supported later.|
+   | origin | String | EH_INTERNAL_KEY | The source about the cmk comes from, it can be:<br> EH_INTERNAL_KEY (generated from the eHSM inside)<br>EH_EXTERNAL_KEY (generated by the customer and want to import into the eHSM)<br><br>**Notes:** currently it only support the type of EH_INTERNAL_KEY. |
+   | purpose | String | EH_PURPOSE_NONE | Record the usage range of the cmk, it can be:<br>EH_PURPOSE_ENCRYPT_DECRYPT<br>EH_PURPOSE_SIGN_VERIFY<br><br>**Notes:** currently this item can be vacant. |
+   | padding mode | String | EH_PAD_RSA_PKCS1 | The padding mode users can use: <br>EH_PAD_RSA_PKCS1 <br>EH_PAD_RSA_PKCS1_OAEP<br>EH_PAD_RSA_PKCS1_PSS<br>EH_PAD_RSA_NO<br><br>**Notes:** Currently, the padding mode is used only for RSA encryption, decryption, and RSA signature verify. RSA encryption and decryption use EH_PAD_RSA_PKCS1_OAEP and EH_PAD_RSA_PKCS1. RSA signature and verify use EH_PAD_RSA_PKCS1_PSS and EH_PAD_RSA_PKCS1. EH_PAD_RSA_NO Currently not supported.|
+   | digest mode | String | EH_SHA_2_256 |The digest mode users can use: <br>EH_SHA_2_224 <br>EH_SHA_2_256<br>EH_SHA_2_384<br>EH_SHA_2_512<br>EH_SM3<br><br>**Notes:** Currently, digest mode is used only for asymmetric key signature verify, and sm2 signature verify only for SM3 digest mode.|
 
   Notes: for the common request parameters, please refer to the [common params](#Common-Prameters)
 
@@ -1833,4 +1836,3 @@ Restores a deleted secret.
   *(return to the [Key Management APIs](#eHSM-REST-API-Reference).)*
 ---
 
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