+ * @param index index of the area
+ * @param perm TPM_NV_ATTRIBUTES of the area
+ * @param size size of the area
+ * @return return code of the operation
+ */
+uint32_t tpm_nv_define_space(uint32_t index, uint32_t perm, uint32_t size);
+
+/**
+ * Issue a TPM_NV_ReadValue command. This implementation is limited
+ * to read the area from offset 0. The area index could be one of
+ * the special value listed in enum tpm_nv_index.
+ *
+ * @param index index of the area
+ * @param data output buffer of the area contents
+ * @param count size of output buffer
+ * @return return code of the operation
+ */
+uint32_t tpm_nv_read_value(uint32_t index, void *data, uint32_t count);
+
+/**
+ * Issue a TPM_NV_WriteValue command. This implementation is limited
+ * to write the area from offset 0. The area index could be one of
+ * the special value listed in enum tpm_nv_index.
+ *
+ * @param index index of the area
+ * @param data input buffer to be wrote to the area
+ * @param length length of data bytes of input buffer
+ * @return return code of the operation
+ */
+uint32_t tpm_nv_write_value(uint32_t index, const void *data, uint32_t length);
+
+/**
+ * Issue a TPM_Extend command.
+ *
+ * @param index index of the PCR
+ * @param in_digest 160-bit value representing the event to be
+ * recorded
+ * @param out_digest 160-bit PCR value after execution of the
+ * command
+ * @return return code of the operation
+ */
+uint32_t tpm_extend(uint32_t index, const void *in_digest, void *out_digest);
+
+/**
+ * Issue a TPM_PCRRead command.