MifareClassic

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public final class MifareClassic
extends Object implements TagTechnology

java.lang.Object
↳	android.nfc.tech.MifareClassic

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Provides access to MIFARE Classic properties and I/O operations on a Tag.

Acquire a MifareClassic object using get(Tag).

MIFARE Classic is also known as MIFARE Standard.

MIFARE Classic tags are divided into sectors, and each sector is sub-divided into blocks. Block size is always 16 bytes (BLOCK_SIZE. Sector size varies.

• MIFARE Classic Mini are 320 bytes (SIZE_MINI), with 5 sectors each of 4 blocks.
• MIFARE Classic 1k are 1024 bytes (SIZE_1K), with 16 sectors each of 4 blocks.
• MIFARE Classic 2k are 2048 bytes (SIZE_2K), with 32 sectors each of 4 blocks.
• MIFARE Classic 4k are 4096 bytes (SIZE_4K). The first 32 sectors contain 4 blocks and the last 8 sectors contain 16 blocks.

MIFARE Classic tags require authentication on a per-sector basis before any other I/O operations on that sector can be performed. There are two keys per sector, and ACL bits determine what I/O operations are allowed on that sector after authenticating with a key. and .

Three well-known authentication keys are defined in this class: KEY_DEFAULT, KEY_MIFARE_APPLICATION_DIRECTORY, KEY_NFC_FORUM.

• KEY_DEFAULT is the default factory key for MIFARE Classic.
• KEY_MIFARE_APPLICATION_DIRECTORY is the well-known key for MIFARE Classic cards that have been formatted according to the MIFARE Application Directory (MAD) specification.
• KEY_NFC_FORUM is the well-known key for MIFARE Classic cards that have been formatted according to the NXP specification for NDEF on MIFARE Classic.

  Implementation of this class on a Android NFC device is optional. If it is not implemented, then MifareClassic will never be enumerated in Tag#getTechList. If it is enumerated, then all MifareClassic I/O operations will be supported, and Ndef#MIFARE_CLASSIC NDEF tags will also be supported. In either case, NfcA will also be enumerated on the tag, because all MIFARE Classic tags are also NfcA.

  Note: Methods that perform I/O operations require the Manifest.permission.NFC permission.

  See also:

  • authenticateSectorWithKeyA(int, byte)
  • authenticateSectorWithKeyB(int, byte)

  Summary

  Constants
  int	BLOCK_SIZE Size of a MIFARE Classic block (in bytes)
  int	SIZE_1K Tag contains 16 sectors, each with 4 blocks.
  int	SIZE_2K Tag contains 32 sectors, each with 4 blocks.
  int	SIZE_4K Tag contains 40 sectors.
  int	SIZE_MINI Tag contains 5 sectors, each with 4 blocks.
  int	TYPE_CLASSIC A MIFARE Classic tag
  int	TYPE_PLUS A MIFARE Plus tag
  int	TYPE_PRO A MIFARE Pro tag
  int	TYPE_UNKNOWN A MIFARE Classic compatible card of unknown type

  Fields
  public static final byte[]	KEY_DEFAULT The default factory key.
  public static final byte[]	KEY_MIFARE_APPLICATION_DIRECTORY The well-known key for tags formatted according to the MIFARE Application Directory (MAD) specification.
  public static final byte[]	KEY_NFC_FORUM The well-known key for tags formatted according to the NDEF on MIFARE Classic specification.

  Public methods
  boolean	authenticateSectorWithKeyA(int sectorIndex, byte[] key) Authenticate a sector with key A.
  boolean	authenticateSectorWithKeyB(int sectorIndex, byte[] key) Authenticate a sector with key B.
  int	blockToSector(int blockIndex) Return the sector that contains a given block.
  void	close() Disable I/O operations to the tag from this TagTechnology object, and release resources.
  void	connect() Enable I/O operations to the tag from this TagTechnology object.
  void	decrement(int blockIndex, int value) Decrement a value block, storing the result in the temporary block on the tag.
  static MifareClassic	get(Tag tag) Get an instance of MifareClassic for the given tag.
  int	getBlockCount() Return the total number of MIFARE Classic blocks.
  int	getBlockCountInSector(int sectorIndex) Return the number of blocks in the given sector.
  int	getMaxTransceiveLength() Return the maximum number of bytes that can be sent with transceive(byte).
  int	getSectorCount() Return the number of MIFARE Classic sectors.
  int	getSize() Return the size of the tag in bytes One of SIZE_MINI, SIZE_1K, SIZE_2K, SIZE_4K.
  Tag	getTag() Get the Tag object backing this TagTechnology object.
  int	getTimeout() Get the current transceive(byte) timeout in milliseconds.
  int	getType() Return the type of this MIFARE Classic compatible tag.
  void	increment(int blockIndex, int value) Increment a value block, storing the result in the temporary block on the tag.
  boolean	isConnected() Helper to indicate if I/O operations should be possible.
  byte[]	readBlock(int blockIndex) Read 16-byte block.
  void	restore(int blockIndex) Copy from a value block to the temporary block.
  int	sectorToBlock(int sectorIndex) Return the first block of a given sector.
  void	setTimeout(int timeout) Set the transceive(byte) timeout in milliseconds.
  byte[]	transceive(byte[] data) Send raw NfcA data to a tag and receive the response.
  void	transfer(int blockIndex) Copy from the temporary block to a value block.
  void	writeBlock(int blockIndex, byte[] data) Write 16-byte block.

  Inherited methods
  From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  From interface android.nfc.tech.TagTechnology abstract void close() Disable I/O operations to the tag from this TagTechnology object, and release resources. abstract void connect() Enable I/O operations to the tag from this TagTechnology object. abstract Tag getTag() Get the Tag object backing this TagTechnology object. abstract boolean isConnected() Helper to indicate if I/O operations should be possible.
  From interface java.io.Closeable abstract void close() Closes this stream and releases any system resources associated with it.
  From interface java.lang.AutoCloseable abstract void close() Closes this resource, relinquishing any underlying resources.

  Constants

  BLOCK_SIZE

  Added in API level 10

  public static final int BLOCK_SIZE

  Size of a MIFARE Classic block (in bytes)

  Constant Value: 16 (0x00000010)

  SIZE_1K

  Added in API level 10

  public static final int SIZE_1K

  Tag contains 16 sectors, each with 4 blocks.

  Constant Value: 1024 (0x00000400)

  SIZE_2K

  Added in API level 10

  public static final int SIZE_2K

  Tag contains 32 sectors, each with 4 blocks.

  Constant Value: 2048 (0x00000800)

  SIZE_4K

  Added in API level 10

  public static final int SIZE_4K

  Tag contains 40 sectors. The first 32 sectors contain 4 blocks and the last 8 sectors contain 16 blocks.

  Constant Value: 4096 (0x00001000)

  SIZE_MINI

  Added in API level 10

  public static final int SIZE_MINI

  Tag contains 5 sectors, each with 4 blocks.

  Constant Value: 320 (0x00000140)

  TYPE_CLASSIC

  Added in API level 10

  public static final int TYPE_CLASSIC

  A MIFARE Classic tag

  Constant Value: 0 (0x00000000)

  TYPE_PLUS

  Added in API level 10

  public static final int TYPE_PLUS

  A MIFARE Plus tag

  Constant Value: 1 (0x00000001)

  TYPE_PRO

  Added in API level 10

  public static final int TYPE_PRO

  A MIFARE Pro tag

  Constant Value: 2 (0x00000002)

  TYPE_UNKNOWN

  Added in API level 10

  public static final int TYPE_UNKNOWN

  A MIFARE Classic compatible card of unknown type

  Constant Value: -1 (0xffffffff)

  Fields

  KEY_DEFAULT

  Added in API level 10

  public static final byte[] KEY_DEFAULT

  The default factory key.

  KEY_MIFARE_APPLICATION_DIRECTORY

  Added in API level 10

  public static final byte[] KEY_MIFARE_APPLICATION_DIRECTORY

  The well-known key for tags formatted according to the MIFARE Application Directory (MAD) specification.

  KEY_NFC_FORUM

  Added in API level 10

  public static final byte[] KEY_NFC_FORUM

  The well-known key for tags formatted according to the NDEF on MIFARE Classic specification.

  Public methods

  authenticateSectorWithKeyA

  Added in API level 10

  public boolean authenticateSectorWithKeyA (int sectorIndex, 
                  byte[] key)

  Authenticate a sector with key A.

  Successful authentication of a sector with key A enables other I/O operations on that sector. The set of operations granted by key A key depends on the ACL bits set in that sector. For more information see the MIFARE Classic specification on http://www.nxp.com.

  A failed authentication attempt causes an implicit reconnection to the tag, so authentication to other sectors will be lost.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  sectorIndex	int: index of sector to authenticate, starting from 0
  key	byte: 6-byte authentication key

  Returns
  boolean	true on success, false on authentication failure

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  authenticateSectorWithKeyB

  Added in API level 10

  public boolean authenticateSectorWithKeyB (int sectorIndex, 
                  byte[] key)

  Authenticate a sector with key B.

  Successful authentication of a sector with key B enables other I/O operations on that sector. The set of operations granted by key B depends on the ACL bits set in that sector. For more information see the MIFARE Classic specification on http://www.nxp.com.

  A failed authentication attempt causes an implicit reconnection to the tag, so authentication to other sectors will be lost.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  sectorIndex	int: index of sector to authenticate, starting from 0
  key	byte: 6-byte authentication key

  Returns
  boolean	true on success, false on authentication failure

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  blockToSector

  Added in API level 10

  public int blockToSector (int blockIndex)

  Return the sector that contains a given block.

  Does not cause any RF activity and does not block.

  Parameters
  blockIndex	int: index of block to lookup, starting from 0

  Returns
  int	sector index that contains the block

  close

  Added in API level 10

  public void close ()

  Disable I/O operations to the tag from this TagTechnology object, and release resources.

  Also causes all blocked I/O operations on other thread to be canceled and return with IOException.

  Requires the Manifest.permission.NFC permission.

  Throws
  IOException

  connect

  Added in API level 10

  public void connect ()

  Enable I/O operations to the tag from this TagTechnology object.

  May cause RF activity and may block. Must not be called from the main application thread. A blocked call will be canceled with IOException by calling close() from another thread.

  Only one TagTechnology object can be connected to a Tag at a time.

  Applications must call close() when I/O operations are complete.

  Requires the Manifest.permission.NFC permission.

  Throws
  IOException

  decrement

  Added in API level 10

  public void decrement (int blockIndex, 
                  int value)

  Decrement a value block, storing the result in the temporary block on the tag.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to decrement, starting from 0
  value	int: non-negative to decrement by

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  get

  Added in API level 10

  public static MifareClassic get (Tag tag)

  Get an instance of MifareClassic for the given tag.

  Does not cause any RF activity and does not block.

  Returns null if MifareClassic was not enumerated in Tag#getTechList. This indicates the tag is not MIFARE Classic compatible, or this Android device does not support MIFARE Classic.

  Parameters
  tag	Tag: an MIFARE Classic compatible tag

  Returns
  MifareClassic	MIFARE Classic object

  getBlockCount

  Added in API level 10

  public int getBlockCount ()

  Return the total number of MIFARE Classic blocks.

  Does not cause any RF activity and does not block.

  Returns
  int	total number of blocks

  getBlockCountInSector

  Added in API level 10

  public int getBlockCountInSector (int sectorIndex)

  Return the number of blocks in the given sector.

  Does not cause any RF activity and does not block.

  Parameters
  sectorIndex	int: index of sector, starting from 0

  Returns
  int	number of blocks in the sector

  getMaxTransceiveLength

  Added in API level 14

  public int getMaxTransceiveLength ()

  Return the maximum number of bytes that can be sent with transceive(byte).

  Returns
  int	the maximum number of bytes that can be sent with transceive(byte).

  getSectorCount

  Added in API level 10

  public int getSectorCount ()

  Return the number of MIFARE Classic sectors.

  Does not cause any RF activity and does not block.

  Returns
  int	number of sectors

  getSize

  Added in API level 10

  public int getSize ()

  Return the size of the tag in bytes

  One of SIZE_MINI, SIZE_1K, SIZE_2K, SIZE_4K. These constants are equal to their respective size in bytes.

  Does not cause any RF activity and does not block.

  Returns
  int	size in bytes

  getTag

  Added in API level 10

  public Tag getTag ()

  Get the Tag object backing this TagTechnology object.

  Returns
  Tag	the Tag backing this TagTechnology object.

  getTimeout

  Added in API level 14

  public int getTimeout ()

  Get the current transceive(byte) timeout in milliseconds.

  Requires the Manifest.permission.NFC permission.

  Returns
  int	timeout value in milliseconds

  Throws
  SecurityException	if the tag object is reused after the tag has left the field

  getType

  Added in API level 10

  public int getType ()

  Return the type of this MIFARE Classic compatible tag.

  One of TYPE_UNKNOWN, TYPE_CLASSIC, TYPE_PLUS or TYPE_PRO.

  Does not cause any RF activity and does not block.

  Returns
  int	type

  increment

  Added in API level 10

  public void increment (int blockIndex, 
                  int value)

  Increment a value block, storing the result in the temporary block on the tag.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to increment, starting from 0
  value	int: non-negative to increment by

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  isConnected

  Added in API level 10

  public boolean isConnected ()

  Helper to indicate if I/O operations should be possible.

  Returns true if connect() has completed, and close() has not been called, and the Tag is not known to be out of range.

  Does not cause RF activity, and does not block.

  Returns
  boolean	true if I/O operations should be possible

  readBlock

  Added in API level 10

  public byte[] readBlock (int blockIndex)

  Read 16-byte block.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to read, starting from 0

  Returns
  byte[]	16 byte block

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  restore

  Added in API level 10

  public void restore (int blockIndex)

  Copy from a value block to the temporary block.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to copy from

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  sectorToBlock

  Added in API level 10

  public int sectorToBlock (int sectorIndex)

  Return the first block of a given sector.

  Does not cause any RF activity and does not block.

  Parameters
  sectorIndex	int: index of sector to lookup, starting from 0

  Returns
  int	block index of first block in sector

  setTimeout

  Added in API level 14

  public void setTimeout (int timeout)

  Set the transceive(byte) timeout in milliseconds.

  The timeout only applies to transceive(byte) on this object, and is reset to a default value when close() is called.

  Setting a longer timeout may be useful when performing transactions that require a long processing time on the tag such as key generation.

  Requires the Manifest.permission.NFC permission.

  Parameters
  timeout	int: timeout value in milliseconds

  Throws
  SecurityException	if the tag object is reused after the tag has left the field

  transceive

  Added in API level 10

  public byte[] transceive (byte[] data)

  Send raw NfcA data to a tag and receive the response.

  This is equivalent to connecting to this tag via NfcA and calling NfcA#transceive. Note that all MIFARE Classic tags are based on NfcA technology.

  Use getMaxTransceiveLength() to retrieve the maximum number of bytes that can be sent with transceive(byte).

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  data	byte

  Returns
  byte[]

  Throws
  IOException

  See also:

  • NfcA.transceive(byte)

  transfer

  Added in API level 10

  public void transfer (int blockIndex)

  Copy from the temporary block to a value block.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to copy to

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled

  writeBlock

  Added in API level 10

  public void writeBlock (int blockIndex, 
                  byte[] data)

  Write 16-byte block.

  This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

  Requires the Manifest.permission.NFC permission.

  Parameters
  blockIndex	int: index of block to write, starting from 0
  data	byte: 16 bytes of data to write

  Throws
  TagLostException	if the tag leaves the field
  IOException	if there is an I/O failure, or the operation is canceled