diff --git a/content.tex b/content.tex
index 4b45678..ab75f78 100644
--- a/content.tex
+++ b/content.tex
@@ -5750,6 +5750,8 @@ descriptor for the \field{sense_len}, \field{residual},
 \field{status_qualifier}, \field{status}, \field{response} and
 \field{sense} fields.
 
+\input{virtio-crypto.tex}
+
 \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 
 Currently there are three device-independent feature bits defined:
diff --git a/virtio-crypto.tex b/virtio-crypto.tex
new file mode 100644
index 0000000..9f7faf0
--- /dev/null
+++ b/virtio-crypto.tex
@@ -0,0 +1,945 @@
+\section{Crypto Device}\label{sec:Device Types / Crypto Device}
+
+The virtio crypto device is a virtual cryptography device as well as a kind of
+virtual hardware accelerator for virtual machines. The encryption and
+decryption requests are placed in the data queue and are ultimately handled by the
+backend crypto accelerators. The second queue is the control queue used to create 
+or destroy sessions for symmetric algorithms and will control some advanced
+features in the future. The virtio crypto device provides the following crypto
+services: CIPHER, MAC, HASH, and AEAD.
+
+
+\subsection{Device ID}\label{sec:Device Types / Crypto Device / Device ID}
+
+20
+
+\subsection{Virtqueues}\label{sec:Device Types / Crypto Device / Virtqueues}
+
+\begin{description}
+\item[0] dataq1
+\item[\ldots]
+\item[N-1] dataqN
+\item[N] controlq
+\end{description}
+
+N is set by \field{max_dataqueues}.
+
+\subsection{Feature bits}\label{sec:Device Types / Crypto Device / Feature bits}
+
+Undefined currently.
+
+\subsection{Device configuration layout}\label{sec:Device Types / Crypto Device / Device configuration layout}
+
+The following driver-read-only configuration fields are defined:
+
+\begin{lstlisting}
+struct virtio_crypto_config {
+    le32 status;
+    le32 max_dataqueues;
+    le32 crypto_services;
+    /* Detailed algorithms mask */
+    le32 cipher_algo_l;
+    le32 cipher_algo_h;
+    le32 hash_algo;
+    le32 mac_algo_l;
+    le32 mac_algo_h;
+    le32 aead_algo;
+    /* Maximum length of cipher key */
+    le32 max_cipher_key_len;
+    /* Maximum length of authenticated key */
+    le32 max_auth_key_len;
+    le32 reserve;
+    /* Maximum size of each crypto request's content */
+    le64 max_size;
+};
+\end{lstlisting}
+
+The value of the \field{status} field is VIRTIO_CRYPTO_S_HW_READY or VIRTIO_CRYPTO_S_STARTED.
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_S_HW_READY  (1 << 0)
+#define VIRTIO_CRYPTO_S_STARTED  (1 << 1)
+\end{lstlisting}
+
+The following driver-read-only fields include \field{max_dataqueues}, which specifies the
+maximum number of data virtqueues (dataq1\ldots dataqN), and \field{crypto_services},
+which indicates the crypto services the virtio crypto supports.
+
+The following services are defined:
+
+\begin{lstlisting}
+/* CIPHER service */
+#define VIRTIO_CRYPTO_SERVICE_CIPHER 0
+/* HASH service */
+#define VIRTIO_CRYPTO_SERVICE_HASH   1
+/* MAC (Message Authentication Codes) service */
+#define VIRTIO_CRYPTO_SERVICE_MAC    2
+/* AEAD (Authenticated Encryption with Associated Data) service */
+#define VIRTIO_CRYPTO_SERVICE_AEAD   3
+\end{lstlisting}
+
+The last driver-read-only fields specify detailed algorithms masks 
+the device offers for corresponding services. The following CIPHER algorithms
+are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_CIPHER                 0
+#define VIRTIO_CRYPTO_CIPHER_ARC4               1
+#define VIRTIO_CRYPTO_CIPHER_AES_ECB            2
+#define VIRTIO_CRYPTO_CIPHER_AES_CBC            3
+#define VIRTIO_CRYPTO_CIPHER_AES_CTR            4
+#define VIRTIO_CRYPTO_CIPHER_DES_ECB            5
+#define VIRTIO_CRYPTO_CIPHER_DES_CBC            6
+#define VIRTIO_CRYPTO_CIPHER_3DES_ECB           7
+#define VIRTIO_CRYPTO_CIPHER_3DES_CBC           8
+#define VIRTIO_CRYPTO_CIPHER_3DES_CTR           9
+#define VIRTIO_CRYPTO_CIPHER_KASUMI_F8          10
+#define VIRTIO_CRYPTO_CIPHER_SNOW3G_UEA2        11
+#define VIRTIO_CRYPTO_CIPHER_AES_F8             12
+#define VIRTIO_CRYPTO_CIPHER_AES_XTS            13
+#define VIRTIO_CRYPTO_CIPHER_ZUC_EEA3           14
+\end{lstlisting}
+
+The following HASH algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_HASH            0
+#define VIRTIO_CRYPTO_HASH_MD5           1
+#define VIRTIO_CRYPTO_HASH_SHA1          2
+#define VIRTIO_CRYPTO_HASH_SHA_224       3
+#define VIRTIO_CRYPTO_HASH_SHA_256       4
+#define VIRTIO_CRYPTO_HASH_SHA_384       5
+#define VIRTIO_CRYPTO_HASH_SHA_512       6
+#define VIRTIO_CRYPTO_HASH_SHA3_224      7
+#define VIRTIO_CRYPTO_HASH_SHA3_256      8
+#define VIRTIO_CRYPTO_HASH_SHA3_384      9
+#define VIRTIO_CRYPTO_HASH_SHA3_512      10
+#define VIRTIO_CRYPTO_HASH_SHA3_SHAKE128      11
+#define VIRTIO_CRYPTO_HASH_SHA3_SHAKE256      12
+\end{lstlisting}
+
+The following MAC algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_MAC                       0
+#define VIRTIO_CRYPTO_MAC_HMAC_MD5                 1
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA1                2
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_224             3
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_256             4
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_384             5
+#define VIRTIO_CRYPTO_MAC_HMAC_SHA_512             6
+#define VIRTIO_CRYPTO_MAC_CMAC_3DES                25
+#define VIRTIO_CRYPTO_MAC_CMAC_AES                 26
+#define VIRTIO_CRYPTO_MAC_KASUMI_F9                27
+#define VIRTIO_CRYPTO_MAC_SNOW3G_UIA2              28
+#define VIRTIO_CRYPTO_MAC_GMAC_AES                 41
+#define VIRTIO_CRYPTO_MAC_GMAC_TWOFISH             42
+#define VIRTIO_CRYPTO_MAC_CBCMAC_AES               49
+#define VIRTIO_CRYPTO_MAC_CBCMAC_KASUMI_F9         50
+#define VIRTIO_CRYPTO_MAC_XCBC_AES                 53
+#define VIRTIO_CRYPTO_MAC_ZUC_EIA3                 54
+\end{lstlisting}
+
+The following AEAD algorithms are defined:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_NO_AEAD     0
+#define VIRTIO_CRYPTO_AEAD_GCM    1
+#define VIRTIO_CRYPTO_AEAD_CCM    2
+#define VIRTIO_CRYPTO_AEAD_CHACHA20_POLY1305  3
+\end{lstlisting}
+
+\begin{note}
+Any other value is reserved for future use.
+\end{note}
+
+\devicenormative{\subsubsection}{Device configuration layout}{Device Types / Crypto Device / Device configuration layout}
+
+\begin{itemize*}
+\item The device MUST set \field{max_dataqueues} to between 1 and 65535 inclusive.
+\item The device MUST set \field{status} based on the status of the hardware-backed implementation. 
+\item The device MUST accept and handle requests after \field{status} is set to VIRTIO_CRYPTO_S_HW_READY.
+\item The device MUST set \field{crypto_services} based on the crypto services the device offers.
+\item The device MUST set detailed algorithms masks based on the \field{crypto_services} field.
+\item The device MUST set \field{max_size} to show the maximum size of crypto request the device supports.
+\item The device MUST set \field{max_cipher_key_len} to show the maximum length of cipher key if the device supports CIPHER service.
+\item The device MUST set \field{max_auth_key_len} to show the maximum length of authenticated key if the device supports MAC service.
+\end{itemize*}
+
+\drivernormative{\subsubsection}{Device configuration layout}{Device Types / Crypto Device / Device configuration layout}
+
+\begin{itemize*}
+\item The driver MUST read the ready \field{status} from the bottom bit of status to check whether the hardware-backed
+      implementation is ready or not, and the driver MUST reread it after the device reset. 
+\item The driver MUST NOT transmit any packets to the device if the ready \field{status} is not set.
+\item The driver MAY read \field{max_dataqueues} field to discover the number of data queues the device supports.
+\item The driver MUST read \field{crypto_services} field to discover which services the device is able to offer.
+\item The driver MUST read the detailed algorithms fields based on \field{crypto_services} field.
+\item The driver SHOULD read \field{max_size} to discover the maximum size of crypto request the device supports.
+\item The driver SHOULD read \field{max_cipher_key_len} to discover the maximum length of cipher key the device supports.
+\item The driver SHOULD read \field{max_auth_key_len} to discover the maximum length of authenticated key the device supports.
+\end{itemize*}
+
+\subsection{Device Initialization}\label{sec:Device Types / Crypto Device / Device Initialization}
+
+\drivernormative{\subsubsection}{Device Initialization}{Device Types / Crypto Device / Device Initialization}
+
+\begin{itemize*}
+\item The driver MUST identify and initialize the control virtqueue.
+\item The driver MUST read the supported crypto services from bits of \field{crypto_services}. 
+\item The driver MUST read the supported algorithms based on \field{crypto_services} field.
+\end{itemize*}
+
+\devicenormative{\subsubsection}{Device Initialization}{Device Types / Crypto Device / Device Initialization}
+
+\begin{itemize*}
+\item The device MUST be configured with at least one accelerator which executes backend crypto operations.
+\item The device MUST write the \field{crypto_services} field based on the capacities of the backend accelerator.
+\end{itemize*}
+
+\subsection{Device Operation}\label{sec:Device Types / Crypto Device / Device Operation}
+
+Packets can be transmitted by placing them in both the controlq and dataq.
+Packets consist of a general header and a service-specific request.
+Where 'general header' is for all crypto requests, and 'service specific requests'
+are composed of operation parameter + output data + input data in general.
+Operation parameters are algorithm-specific parameters, output data is the
+data that should be utilized in operations, and input data is equal to
+"operation result + result data".
+
+\begin{note}
+The basic unit of all data length the byte.
+\end{note}
+
+The general header for controlq is as follows:
+
+\begin{lstlisting}
+#define VIRTIO_CRYPTO_OPCODE(service, op)   (((service) << 8) | (op))
+
+struct virtio_crypto_ctrl_header {
+#define VIRTIO_CRYPTO_CIPHER_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x02)
+#define VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x03)
+#define VIRTIO_CRYPTO_HASH_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x02)
+#define VIRTIO_CRYPTO_HASH_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x03)
+#define VIRTIO_CRYPTO_MAC_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x02)
+#define VIRTIO_CRYPTO_MAC_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x03)
+#define VIRTIO_CRYPTO_AEAD_CREATE_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x02)
+#define VIRTIO_CRYPTO_AEAD_DESTROY_SESSION \
+       VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x03)
+    le32 opcode;
+    le32 algo;
+    le32 flag;
+    /* data virtqueue id */
+    le32 queue_id;
+};
+\end{lstlisting}
+
+The general header of dataq:
+
+\begin{lstlisting}
+struct virtio_crypto_op_header {
+#define VIRTIO_CRYPTO_CIPHER_ENCRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x00)
+#define VIRTIO_CRYPTO_CIPHER_DECRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_CIPHER, 0x01)
+#define VIRTIO_CRYPTO_HASH \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_HASH, 0x00)
+#define VIRTIO_CRYPTO_MAC \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_MAC, 0x00)
+#define VIRTIO_CRYPTO_AEAD_ENCRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x00)
+#define VIRTIO_CRYPTO_AEAD_DECRYPT \
+    VIRTIO_CRYPTO_OPCODE(VIRTIO_CRYPTO_SERVICE_AEAD, 0x01)
+    le32 opcode;
+    /* algo should be service-specific algorithms */
+    le32 algo;
+    /* session_id should be service-specific algorithms */
+    le64 session_id;
+    /* control flag to control the request */
+    le32 flag;
+    le32 padding;
+};
+\end{lstlisting}
+
+The device can set the operation status as follows: VIRTIO_CRYPTO_OK: success;
+VIRTIO_CRYPTO_ERR: failure or device error; VIRTIO_CRYPTO_NOTSUPP: not supported;
+VIRTIO_CRYPTO_INVSESS: invalid session ID when executing crypto operations.
+
+\begin{lstlisting}
+enum VIRITO_CRYPTO_STATUS {
+    VIRTIO_CRYPTO_OK = 0,
+    VIRTIO_CRYPTO_ERR = 1,
+    VIRTIO_CRYPTO_BADMSG = 2,
+    VIRTIO_CRYPTO_NOTSUPP = 3,
+    VIRTIO_CRYPTO_INVSESS = 4,
+    VIRTIO_CRYPTO_MAX
+};
+\end{lstlisting}
+
+\subsubsection{Control Virtqueue}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}
+
+The driver uses the control virtqueue to send control commands to the
+device which handles the non-data plane operations, such as session
+operations (See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}).
+
+The packet of controlq:
+
+\begin{lstlisting}
+struct virtio_crypto_op_ctrl_req {
+    struct virtio_crypto_ctrl_header header;
+
+    union {
+        struct virtio_crypto_sym_create_session_req   sym_create_session;
+        struct virtio_crypto_hash_create_session_req  hash_create_session;
+        struct virtio_crypto_mac_create_session_req   mac_create_session;
+        struct virtio_crypto_aead_create_session_req  aead_create_session;
+        struct virtio_crypto_destroy_session_req      destroy_session;
+    } u;
+};
+\end{lstlisting}
+
+The header is the general header, and the union is of the algorithm-specific type,
+which is set by the driver. All the properties in the union are shown as follows.
+
+\paragraph{Session operation}\label{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation}
+
+The symmetric algorithms involve the concept of sessions. A session is a
+handle which describes the cryptographic parameters to be applied to
+a number of buffers. The data within a session handle includes the following:
+
+\begin{enumerate}
+\item The operation (CIPHER, HASH/MAC or both, and if both, the order in
+      which the algorithms should be applied).
+\item The CIPHER set data, including the CIPHER algorithm and mode,
+      the key and its length, and the direction (encryption or decryption).
+\item The HASH/MAC set data, including the HASH algorithm or MAC algorithm,
+      and hash result length (to allow for truncation).
+\begin{itemize*}
+\item Authenticated mode can refer to MAC, which requires that the key and
+      its length are also specified.
+\item For nested mode, the inner and outer prefix data and length are specified,
+      as well as the outer HASH algorithm.
+\end{itemize*}
+\end{enumerate}
+
+The following structure stores the result of session creation set by the device:
+
+\begin{lstlisting}
+struct virtio_crypto_session_input {
+    /* Device-writable part */
+    le64 session_id;
+    le32 status;
+    le32 padding;
+};
+\end{lstlisting}
+
+A request to destroy a session includes the following information:
+
+\begin{lstlisting}
+struct virtio_crypto_destroy_session_req {
+    /* Device-readable part */
+    le64  session_id;
+    /* Device-writable part */
+    le32  status;
+    le32  padding;
+};
+\end{lstlisting}
+
+\subparagraph{Session operation: HASH session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: HASH session}
+
+The packet of HASH session is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_hash_session_para {
+    /* See VIRTIO_CRYPTO_HASH_* above */
+    le32 algo;
+    /* hash result length */
+    le32 hash_result_len;
+};
+struct virtio_crypto_hash_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_hash_session_para para;
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+\subparagraph{Session operation: MAC session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: MAC session}
+
+The packet of MAC session is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_mac_session_para {
+    /* See VIRTIO_CRYPTO_MAC_* above */
+    le32 algo;
+    /* hash result length */
+    le32 hash_result_len;
+    /* length of authenticated key */
+    le32 auth_key_len;
+    le32 padding;
+};
+
+struct virtio_crypto_mac_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_mac_session_para para;
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+\subparagraph{Session operation: Symmetric algorithms session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: Symmetric algorithms session}
+
+The request of symmetric session includes two parts, CIPHER algorithms and chain
+algorithms (chaining CIPHER and HASH/MAC). The packet for CIPHER session is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_session_para {
+    /* See VIRTIO_CRYPTO_CIPHER* above */
+    le32 algo;
+    /* length of key */
+    le32 keylen;
+#define VIRTIO_CRYPTO_OP_ENCRYPT  1
+#define VIRTIO_CRYPTO_OP_DECRYPT  2
+    /* encryption or decryption */
+    le32 op;
+    le32 padding;
+};
+
+struct virtio_crypto_cipher_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_cipher_session_para para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+The packet for algorithm chaining is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_session_para {
+#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER  1
+#define VIRTIO_CRYPTO_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH  2
+    le32 alg_chain_order;
+/* Plain hash */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_PLAIN    1
+/* Authenticated hash (mac) */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH     2
+/* Nested hash */
+#define VIRTIO_CRYPTO_SYM_HASH_MODE_NESTED   3
+    le32 hash_mode;
+    struct virtio_crypto_cipher_session_para cipher_param;
+    union {
+        struct virtio_crypto_hash_session_para hash_param;
+        struct virtio_crypto_mac_session_para mac_param;
+    } u;
+    /* length of the additional authenticated data (AAD) in bytes */
+    le32 aad_len;
+    le32 padding;
+};
+
+struct virtio_crypto_alg_chain_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_alg_chain_session_para para;
+    /* The cipher key */
+    u8 cipher_key[keylen];
+    /* The authenticated key */
+    u8 auth_key[auth_key_len];
+
+    /* Device-writable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+The packet for symmetric algorithm is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_create_session_req {
+    union {
+        struct virtio_crypto_cipher_session_req cipher;
+        struct virtio_crypto_alg_chain_session_req chain;
+    } u;
+
+    /* Device-readable part */
+
+/* No operation */
+#define VIRTIO_CRYPTO_SYM_OP_NONE  0
+/* Cipher only operation on the data */
+#define VIRTIO_CRYPTO_SYM_OP_CIPHER  1
+/* Chain any cipher with any hash or mac operation. The order
+   depends on the value of alg_chain_order param */
+#define VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING  2
+    le32 op_type;
+    le32 padding;
+};
+\end{lstlisting}
+
+\subparagraph{Session operation: AEAD session}\label{sec:Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: AEAD session}
+
+The packet for AEAD session is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_aead_session_para {
+    /* See VIRTIO_CRYPTO_AEAD_* above */
+    le32 algo;
+    /* length of key */
+    le32 key_len;
+    /* hash result length */
+    le32 hash_result_len;
+    /* The length of the additional authenticated data (AAD) in bytes */
+    le32 aad_len;
+    /* encryption or decryption, See above VIRTIO_CRYPTO_* */
+    le32 op;
+    le32 padding;
+};
+
+struct virtio_crypto_aead_create_session_req {
+    /* Device-readable part */
+    struct virtio_crypto_aead_session_para para;
+    u8 key[key_len];
+
+    /* Device-writeable part */
+    struct virtio_crypto_session_input input;
+};
+\end{lstlisting}
+
+\drivernormative{\subparagraph}{Session operation: create session}{Device Types / Crypto Device / Device Operation / Control Virtqueue / Session operation / Session operation: create session}
+
+\begin{itemize*}
+\item The driver MUST set the control general header and corresponding properties of the union in structure virtio_crypto_op_ctrl_req. See \ref{sec:Device Types / Crypto Device / Device Operation / Control Virtqueue}.
+\item The driver MUST set \field{opcode} field based on service type: CIPHER, HASH, MAC, or AEAD.
+\item The driver MUST set \field{queue_id} field to show used dataq.
+\end{itemize*}
+
+\devicenormative{\subparagraph}{Session operation: create session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: create session}
+
+\begin{itemize*}
+\item The device MUST set \field{session_id} field as a session identifier return to the driver when the device finishes processing session creation.
+\item The device MUST set \field{status} field to one of the values of enum VIRITO_CRYPTO_STATUS.
+\end{itemize*}
+
+\drivernormative{\subparagraph}{Session operation: destroy session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: destroy session}
+
+\begin{itemize*}
+\item The driver MUST set \field{opcode} field based on service type: CIPHER, HASH, MAC, or AEAD.
+\item The driver MUST set the \field{session_id} to a valid value which assigned by the device when a session is created.
+\end{itemize*}
+
+\devicenormative{\subparagraph}{Session operation: destroy session}{Device Types / Crypto Device / Device
+Operation / Control Virtqueue / Session operation / Session operation: destroy session}
+
+\begin{itemize*}
+\item The device MUST set \field{status} field to one of the values of enum VIRITO_CRYPTO_STATUS.
+\end{itemize*}
+
+\subsubsection{Data Virtqueue}\label{sec:Device Types / Crypto Device / Device Operation / Data Virtqueue}
+
+The driver uses the data virtqueue to transmit the requests of crypto operation to the device,
+and completes the data plane operations (such as crypto operation).
+
+The packet of dataq is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_op_data_req {
+    struct virtio_crypto_op_header header;
+
+    union {
+        struct virtio_crypto_sym_data_req   sym_req;
+        struct virtio_crypto_hash_data_req  hash_req;
+        struct virtio_crypto_mac_data_req   mac_req;
+        struct virtio_crypto_aead_data_req  aead_req;
+    } u;
+};
+\end{lstlisting}
+
+The header is the general header and the union is of the algorithm-specific type,
+which is set by the driver. All properties in the union are shown as follows.
+
+There is a unified input header structure for all crypto services.
+
+The structure is defined as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_inhdr {
+    u8 status;
+};
+\end{lstlisting}
+
+\subsubsection{HASH Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+\begin{lstlisting}
+struct virtio_crypto_hash_para {
+    /* length of source data */
+    le32 src_data_len;
+    /* hash result length */
+    le32 hash_result_len;
+};
+
+struct virtio_crypto_hash_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_hash_para para;
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_hash_data_req structure to store information
+used to run the HASH operations. 
+
+The information includes the hash parameters stored by \field{para}, output data and input data.
+The output data here includes the source data and the input data includes the hash result data used to save the results of the HASH operations.
+\field{inhdr} stores status of executing the HASH operations.
+
+\drivernormative{\paragraph}{HASH Service Operation}{Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+\begin{itemize*}
+\item The driver MUST set the \field{session_id} in struct virtio_crypto_op_header to a valid value which assigned by the device when a session is created.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_HASH.
+\item The driver MUST set the \field{queue_id} field to show used dataq in struct virtio_crypto_op_header.
+\end{itemize*}
+
+\devicenormative{\paragraph}{HASH Service Operation}{Device Types / Crypto Device / Device Operation / HASH Service Operation}
+
+\begin{itemize*}
+\item The device MUST copy the results of HASH operations to the hash_result[] if HASH operations success.
+\item The device MUST set \field{status} in struct virtio_crypto_inhdr to one of the values of enum VIRITO_CRYPTO_STATUS.
+\end{itemize*}
+
+\subsubsection{MAC Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+\begin{lstlisting}
+struct virtio_crypto_mac_para {
+    struct virtio_crypto_hash_para hash;
+};
+
+struct virtio_crypto_mac_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_mac_para para;
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_mac_data_req structure to store information
+used to run the MAC operations. 
+
+The information includes the hash parameters stored by \field{para}, output data and input data.
+The output data here includes the source data and the input data includes the hash result data used to save the results of the MAC operations.
+\field{inhdr} stores status of executing the MAC operations.
+
+\drivernormative{\paragraph}{MAC Service Operation}{Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+\begin{itemize*}
+\item The driver MUST set the \field{session_id} in struct virtio_crypto_op_header to a valid value which assigned by the device when a session is created.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_MAC.
+\item The driver MUST set the \field{queue_id} field to show used dataq in struct virtio_crypto_op_header.
+\end{itemize*}
+
+\devicenormative{\paragraph}{MAC Service Operation}{Device Types / Crypto Device / Device Operation / MAC Service Operation}
+
+\begin{itemize*}
+\item The device MUST copy the results of MAC operations to the hash_result[] if HASH operations success.
+\item The device MUST set \field{status} in struct virtio_crypto_inhdr to one of the values of enum VIRITO_CRYPTO_STATUS.
+\end{itemize*}
+
+\subsubsection{Symmetric algorithms Operation}\label{sec:Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+The packet of plain CIPHER service is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_cipher_para {
+    /*
+     * Byte Length of valid IV/Counter data pointed to by the below iv data.
+     *
+     * For block ciphers in CBC or F8 mode, or for Kasumi in F8 mode, or for
+     *   SNOW3G in UEA2 mode, this is the length of the IV (which
+     *   must be the same as the block length of the cipher).
+     * For block ciphers in CTR mode, this is the length of the counter
+     *   (which must be the same as the block length of the cipher).
+     */
+    le32 iv_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of destination data */
+    le32 dst_data_len;
+    le32 padding;
+};
+
+struct virtio_crypto_cipher_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_cipher_para para;
+    /*
+     * Initialization Vector or Counter data.
+     *
+     * For block ciphers in CBC or F8 mode, or for Kasumi in F8 mode, or for
+     *   SNOW3G in UEA2 mode, this is the Initialization Vector (IV)
+     *   value.
+     * For block ciphers in CTR mode, this is the counter.
+     * For AES-XTS, this is the 128bit tweak, i, from IEEE Std 1619-2007.
+     *
+     * The IV/Counter will be updated after every partial cryptographic
+     * operation.
+     */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+The packet of algorithm chaining is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_alg_chain_data_para {
+    le32 iv_len;
+    /* Length of source data */
+    le32 src_data_len;
+    /* Length of destination data */
+    le32 dst_data_len;
+    /* Starting point for cipher processing in source data */
+    le32 cipher_start_src_offset;
+    /* Length of the source data that the cipher will be computed on */
+    le32 len_to_cipher;
+    /* Starting point for hash processing in source data */
+    le32 hash_start_src_offset;
+    /* Length of the source data that the hash will be computed on */
+    le32 len_to_hash;
+    /* Length of the additional auth data */
+    le32 aad_len;
+    /* Length of the hash result */
+    le32 hash_result_len;
+    le32 reserved;
+};
+
+struct virtio_crypto_alg_chain_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_alg_chain_data_para para;
+    /* Initialization Vector or Counter data */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+    /* Additional authenticated data if exists  */
+    u8 aad[aad_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+The packet of symmetric algorithm is as follows:
+
+\begin{lstlisting}
+struct virtio_crypto_sym_data_req {
+    union {
+        struct virtio_crypto_cipher_data_req cipher;
+        struct virtio_crypto_alg_chain_data_req chain;
+    } u;
+
+    /* Device-readable part */
+
+    /* See above VIRTIO_CRYPTO_SYM_OP_* */
+    le32 op_type;
+    le32 padding;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_sym_data_req structure to store information
+used to run the CIPHER operations. 
+
+The information includes the hash parameters stored by \field{para}, output data and input data.
+In the first virtio_crypto_cipher_para structure, \field{iv_len} specifies the length of the initialization vector or counter,
+\field{src_data_len} specifies the length of the source data, and \field{dst_data_len} specifies the
+length of the destination data. 
+For plain CIPHER operations, the output data here includes the IV/Counter data and source data, and the input data includes the destination data used to save the results of the CIPHER operations.
+
+For algorithms chain, the output data here includes the IV/Counter data, source data and additional authenticated data if exists.
+The input data includes both destination data and hash result data used to store the results of the HASH/MAC operations.
+\field{inhdr} stores status of executing the crypto operations.
+
+\drivernormative{\paragraph}{Symmetric algorithms Operation}{Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+\begin{itemize*}
+\item The driver MUST set the \field{session_id} in struct virtio_crypto_op_header to a valid value which assigned by the device when a session is created.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_CIPHER_ENCRYPT or VIRTIO_CRYPTO_CIPHER_DECRYPT.
+\item The driver MUST set the \field{queue_id} field to show used dataq in struct virtio_crypto_op_header.
+\item The driver MUST specify the fields of struct virtio_crypto_cipher_data_req in struct virtio_crypto_sym_data_req if the created session is based on VIRTIO_CRYPTO_SYM_OP_CIPHER.
+\item The driver MUST specify the fields of both struct virtio_crypto_cipher_data_req and struct virtio_crypto_mac_data_req in struct virtio_crypto_sym_data_req if the created session
+\item is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING type and in the VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH mode.
+\end{itemize*}
+
+\devicenormative{\paragraph}{Symmetric algorithms Operation}{Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation}
+
+\begin{itemize*}
+\item The device MUST parse the virtio_crypto_sym_data_req based on the \field{opcode} in general header.
+\item The device SHOULD only parse fields of struct virtio_crypto_cipher_data_req in struct virtio_crypto_sym_data_req if the created session is VIRTIO_CRYPTO_SYM_OP_CIPHER type.
+\item The device MUST parse fields of both struct virtio_crypto_cipher_data_req and struct virtio_crypto_mac_data_req in struct virtio_crypto_sym_data_req if the created
+session is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING operation type and in the VIRTIO_CRYPTO_SYM_HASH_MODE_AUTH mode.
+\item The device MUST copy the result of cryptographic operation to the dst_data[] in both plain CIPHER mode and algorithms chain mode.
+\item The device MUST check the \field{para}.\field{add_len} is bigger than 0 before parse the additional authenticated data in plain algorithms chain mode.
+\item The device MUST copy the result of HASH/MAC operation to the hash_result[] is of the VIRTIO_CRYPTO_SYM_OP_ALGORITHM_CHAINING type.
+\item The device MUST set the \field{status} field in struct virtio_crypto_inhdr to one of the values of enum VIRITO_CRYPTO_STATUS.
+\end{itemize*}
+
+\paragraph{Steps of Operation}\label{sec:Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation / Steps of Operation}
+
+\subparagraph{Step1: Create session}\label{sec:Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation / Steps of Operation / Step1: Create session}
+
+\begin{enumerate}
+\item The driver specifies information in struct virtio_crypto_op_ctrl_req, including the algorithm name, key, keylen etc;
+\item The driver adds the request of session creation into the controlq's Vring Descriptor Table;
+\item The driver kicks the device;
+\item The device receives the request from controlq;
+\item The device parses information about the request, and determines the information concerning the backend crypto accelerator;
+\item The device packs information based on the APIs of the backend crypto accelerator;
+\item The device invokes the session creation APIs of the backend crypto accelerator to create a session;
+\item The device returns the session id to the driver.
+\end{enumerate}
+
+\subparagraph{Step2: Execute cryptographic operation}\label{sec:Device Types / Crypto Device / Device Operation / Symmetric algorithms Operation / Steps of Operation / Step2: Execute cryptographic operation}
+
+\begin{enumerate}
+\item The driver specifies information in struct virtio_crypto_op_data_req, including struct virtio_crypto_op_header and struct virtio_crypto_sym_data_req, see \ref{sec:Device Types / Crypto Device / Device
+      Operation / Symmetric algorithms Operation};
+\item The driver adds the request for cryptographic operation into the dataq's Vring Descriptor Table;
+\item The driver kicks the device (Or the device actively polls the dataq's Vring Descriptor Table);
+\item The device receives the request from dataq;
+\item The device parses information about the request, and determines the identification information for the backend crypto accelerator. For example, converting guest physical addresses to host physical addresses;
+\item The device packs identification information based on the API of the backend crypto accelerator;
+\item The device invokes the cryptographic APIs of the backend crypto accelerator;
+\item The backend crypto accelerator executes the cryptographic operation implicitly;
+\item The device receives the cryptographic results from the backend crypto accelerator (synchronous or asynchronous);
+\item The device sets the \field{status} in struct virtio_crypto_inhdr;
+\item The device updates and flushes the Used Ring to return the cryptographic results to the driver;
+\item The device notifies the driver (Or the driver actively polls the dataq's Used Ring);
+\item The driver saves the cryptographic result.
+\end{enumerate}
+
+\begin{note}
+\begin{itemize*}
+\item For better performance, the device should by preference use vhost scheme (user space or kernel space)
+      as the backend crypto accelerator in the real production environment.
+\end{itemize*}
+\end{note}
+
+\subsubsection{AEAD Service Operation}\label{sec:Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+\begin{lstlisting}
+struct virtio_crypto_aead_para {
+    /*
+     * Byte Length of valid IV data.
+     *
+     * For GCM mode, this is either 12 (for 96-bit IVs) or 16, in which
+     *   case iv points to J0.
+     * For CCM mode, this is the length of the nonce, which can be in the
+     *   range 7 to 13 inclusive.
+     */
+    le32 iv_len;
+    /* length of additional auth data */
+    le32 aad_len;
+    /* length of source data */
+    le32 src_data_len;
+    /* length of dst data */
+    le32 dst_data_len;
+    /* Length of the hash result */
+    le32 hash_result_len;
+    le32 reserver;
+};
+
+struct virtio_crypto_aead_data_req {
+    /* Device-readable part */
+    struct virtio_crypto_aead_para para;
+    /*
+     * Initialization Vector data.
+     *
+     * For GCM mode, this is either the IV (if the length is 96 bits) or J0
+     *   (for other sizes), where J0 is as defined by NIST SP800-38D.
+     *   Regardless of the IV length, a full 16 bytes needs to be allocated.
+     * For CCM mode, the first byte is reserved, and the nonce should be
+     *   written starting at &iv[1] (to allow space for the implementation
+     *   to write in the flags in the first byte).  Note that a full 16 bytes
+     *   should be allocated, even though the iv_len field will have
+     *   a value less than this.
+     *
+     * The IV will be updated after every partial cryptographic operation.
+     */
+    u8 iv[iv_len];
+    /* Source data */
+    u8 src_data[src_data_len];
+    /* Additional authenticated data if exists  */
+    u8 aad[aad_len];
+
+    /* Device-writable part */
+    /* Destination data */
+    u8 dst_data[dst_data_len];
+    /* Hash result data */
+    u8 hash_result[hash_result_len];
+    struct virtio_crypto_inhdr inhdr;
+};
+\end{lstlisting}
+
+Each data request uses virtio_crypto_aead_data_req structure to store information
+used to run the AEAD operations. 
+
+The information includes the hash parameters stored by \field{para}, output data and input data.
+In the first virtio_crypto_aead_para structure, \field{iv_len} specifies the length of the initialization vector.
+\field{aad_len} specifies the length of additional authentication data, \field{src_data_len} specifies the
+length of the source data; \field{dst_data_len} specifies the length of the destination data.
+The output data here includes the IV data and source data, and the input data includes the destination data used to save the results of the CIPHER operations.
+
+The output data here includes the IV/Counter data, source data and additional authenticated data if exists.
+The input data includes both destination data used to save the results of the AEAD operations.
+\field{inhdr} stores status of executing the AEAD operations.
+
+\drivernormative{\paragraph}{AEAD Service Operation}{Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+\begin{itemize*}
+\item The driver MUST set the \field{session_id} in struct virtio_crypto_op_header to a valid value which assigned by the device when a session is created.
+\item The driver MUST set \field{opcode} in struct virtio_crypto_op_header to VIRTIO_CRYPTO_AEAD_ENCRYPT or VIRTIO_CRYPTO_AEAD_DECRYPT.
+\item The driver MUST set the \field{queue_id} field to show used dataq in struct virtio_crypto_op_header.
+\end{itemize*}
+
+\devicenormative{\paragraph}{AEAD Service Operation}{Device Types / Crypto Device / Device Operation / AEAD Service Operation}
+
+\begin{itemize*}
+\item The device MUST parse the virtio_crypto_aead_data_req based on the \field{opcode} in general header.
+\item The device MUST copy the result of cryptographic operation to the dst_data[].
+\item The device MUST copy the hash result to the hash_result[].
+\item The device MUST set the \field{status} field in struct virtio_crypto_inhdr to one of the values of enum VIRITO_CRYPTO_STATUS.
+\item When the \field{opcode} is VIRTIO_CRYPTO_AEAD_DECRYPT, the device MUST verify and return the verification result to the driver, and if the verification result is incorrect, VIRTIO_CRYPTO_BADMSG (bad message) MUST be returned to the driver.
+\end{itemize*}
\ No newline at end of file
