Intel

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FlashStorage

com.intel.util

Class FlashStorage

  • java.lang.Object
    • com.intel.util.FlashStorage


  • public class FlashStorage
    extends java.lang.Object

    This class exposes flash storage access APIs for the applets.

    In general, using flash for applets data storage is not recommended since the flash space available for applets is very limited. In addition, by default applets are not granted flash storage access permissions, unless explicitly specified in the permissions section of the applet installation package. The applet data is stored in flash as an encrypted BLOB with integrity protection. Each applet can only access its own flash data. However, different sessions of the same applet are sharing flash resources and access the exact same files. Currently, only one flash data file per applet is supported. Due to flash wear-out considerations, an applet is allowed to use up to 100 write/erase flash data operations per machine boot. In addition, the applet allowed operations counter will be reset again 24 hours after the applet was installed and every 24 hours since the last write/erase operation.

    Instead of using flash storage, applets should use offline data storage (for example, hard disk) for saving their non-volatile data.

    File Properties
    Default values for non-existing file are:
    • Field Summary

      Fields
      Modifier and Type Field and Description
      static int FLASH_STORAGE_PROPERTY_ANTI_REPLAY
      If property is set to true, the files are stored with anti-replay protection.
    • Method Summary

      Methods
      Modifier and Type Method and Description
      static void eraseFlashData(int fileName)
      Removes the specified applet file from the flash. Note: after erasing the file all file properties are restored to default
      static int getFlashDataSize(int fileName)
      Returns the size of the specified applet file on the flash.
      static int getMaxFileName()
      Returns the maximum file name value that can be used in this class.
      static boolean getProperty(int fileName, int propertyId)
      Returns the value of a specific algorithm property for a given file
      static int readFlashData(int fileName, byte[] dest, int destOff)
      Reads the data from the specified applet file in flash and copies it into the given destination array.
      static void setProperty(int fileName, int propertyId, boolean state)
      Sets a property that modifies the algorithm behavior for a given file Notes: Properties can only be modified on non existing files. Properties are saved only after creating a file using writeFlashData(int, byte[], int, int)
      static void writeFlashData(int fileName, byte[] src, int srcOff, int srcLen)
      Writes the provided data into the specified applet file in the flash.
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, toString
    • Field Detail

      • FLASH_STORAGE_PROPERTY_ANTI_REPLAY

        public static final int FLASH_STORAGE_PROPERTY_ANTI_REPLAY
        If property is set to true, the files are stored with anti-replay protection. Default is false. Note that this resource is limited and setting this property might fail if more than a given amount of anti-replay files are already being used
        See Also:
        Constant Field Values
    • Method Detail

      • getFlashDataSize

        public static int getFlashDataSize(int fileName)
                                    throws UtilException
        Returns the size of the specified applet file on the flash.
        Parameters:
        fileName - the index of the file. getMaxFileName() indicates the maximum file number value (including) that can be used.
        Returns:
        The size of the applet file in flash. For invalid/non existent files, the returned size will be 0.
        Throws:
        IllegalParameterException - if the file's index is invalid.
        UtilSecurityException - if the file was identified as compromised.
        UtilException - some internal error occurred.
      • readFlashData

        public static int readFlashData(int fileName,
                        byte[] dest,
                        int destOff)
                                 throws UtilException
        Reads the data from the specified applet file in flash and copies it into the given destination array.
        Parameters:
        fileName - the index of the file to read. getMaxFileName() indicates the maximum file number value (including) that can be used.
        dest - the destination array to hold the file data
        destOff - the offset in dest array
        Returns:
        The number of bytes copied into dest array.
        Throws:
        FileNotFoundException - if the file doesn't exist.
        IllegalParameterException - if the file's index is invalid.
        UtilSecurityException - if the file was identified as compromised.
        UtilException - some internal error occurred.
      • writeFlashData

        public static void writeFlashData(int fileName,
                          byte[] src,
                          int srcOff,
                          int srcLen)
                                   throws UtilException
        Writes the provided data into the specified applet file in the flash.
        Parameters:
        fileName - the index of the file to write. getMaxFileName() indicates the maximum file number value (including) that can be used.
        src - an array holding the data to be copied into the file
        srcOff - the offset in src array
        srcLen - the length of the data to write
        Throws:
        AccessDeniedException - if the size of the new data along with any other flash data already allocated for this applet exceeds the applet flash quota.
        FlashWearoutException - if the flash wearout mechanism blocked the write/erase, or if the applet exhausted the number of operations allowed for the current period.
        UtilOutOfResourcesException - if a property was set to a state that causes resources exhaustion (e.g. setting the property FLASH_STORAGE_PROPERTY_ANTI_REPLAY to true can cause the exception after reaching max of resources}) of not enough flash storage left
        IllegalParameterException - if the file's index is invalid.
        UtilSecurityException - if the file was identified as compromised.
        UtilException - in case of internal error.
      • eraseFlashData

        public static void eraseFlashData(int fileName)
                                   throws UtilException
        Removes the specified applet file from the flash. Note: after erasing the file all file properties are restored to default
        Parameters:
        fileName - the index of the file to remove. getMaxFileName() indicates the maximum file number value (including) that can be used.
        Throws:
        FlashWearoutException - if the flash wearout mechanism blocked the write/erase, or if the applet exhausted the number of operations allowed for the current period.
        IllegalParameterException - if the file's index is invalid.
        FileNotFoundException - if the file doesn't exist.
        UtilSecurityException - if the file was identified as compromised.
        UtilException - in case of internal error.
      • setProperty

        public static void setProperty(int fileName,
                       int propertyId,
                       boolean state)
                                throws UtilException
        Sets a property that modifies the algorithm behavior for a given file Notes:
        Parameters:
        fileName - the index of the file. getMaxFileName() indicates the maximum file number value (including) that can be used.
        propertyId - the property to be set, one of FLASH_STORAGE_PROPERTY_XYZ
        state - determines whether the property is enabled or disabled
        Throws:
        IllegalParameterException - if one of the following occurs:
        • the file's index is invalid
        • propertyId is unknown
        IllegalUseException - if the fileName already exists and was saved with a different property state
        UtilSecurityException - if the file was identified as compromised.
        UtilException - for any other error
      • getProperty

        public static boolean getProperty(int fileName,
                          int propertyId)
                                   throws UtilException
        Returns the value of a specific algorithm property for a given file
        Parameters:
        fileName - the index of the file. getMaxFileName() indicates the maximum file number value (including) that can be used.
        propertyId - the property to get, one of FLASH_STORAGE_PROPERTY_XYZ
        Returns:
        Returns whether a specific property is disabled or enabled
        Throws:
        IllegalParameterException - if one of the following occurs:
        • the file's index is invalid
        • propertyId is unknown
        UtilSecurityException - if the file was identified as compromised.
        UtilException - for any other error
      • getMaxFileName

        public static int getMaxFileName()
        Returns the maximum file name value that can be used in this class.
        Returns:
        The maximum file name value that can be used in this class.