Added in API level 10

Summary: Constants | Fields | Methods | Inherited Methods

MifareClassic

Kotlin |Java

public final class MifareClassic
extends Object implements TagTechnology

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

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:

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


      close()

Closes this stream and releases any system resources associated with it.

From interface


        
          java.lang.AutoCloseable


      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.

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.

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.

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.

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.

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).

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.

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.

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