A typical use case for this class might be as follows:
OneWireContainer18 coprOWC18 = new OneWireContainer18(adapter,address);
//COPR.0 is the filename for coprocessor service data SHAiButtonCopr copr = new SHAiButtonCopr(coprOWC18,"COPR.0");
//Initial amount for new users is $100, and debit amount is 50 cents SHATransaction trans = new SHADebit(copr, 10000, 50);
OneWireContainer18 owc18 = new OneWireContainer18(adapter, userAddress);
//The following constructor erases all transaction data from the user and //installs the system authentication secret on the user iButton. SHAiButtonUser user = new SHAiButtonUser18(copr, owc18, true, authSecret);
//creates account data on iButton if(trans.setupTransactionData(user)) System.out.println("Account data installed successfully"); else System.out.println("Account data installation failed");
//... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
//"challenges" user iButton if(trans.verifyUser(user)) { System.out.println("User Verified Successfully");
//checks data signature and account balance>0 if(trans.verifyTransactionData(user)) { System.out.println("Account Data Verified Successfully");
//debits and writes new data to user iButton if(trans.executeTransaction(user)) { System.out.println("Account debited."); System.out.println("New Balance: " + trans.getParameter(SHADebit.USER_BALANCE)); } } }
//... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
if(trans.getLastError()!=0) { System.err.println("Error code: " + trans.getLastError()); }
This class makes use of several performance enhancements for TINI. For instance, most methods are synchronized
to access instance variable byte arrays rather than creating new byte arrays every time a transaction is performed. This could hurt performance in multi-threaded applications, but the usefulness of having several threads contending to talk to a single iButton is questionable since the methods in com.dalsemi.onewire.adapter.DSPortAdapter
beginExclusive(boolean)
and endExclusive()
should be used.
Public Member Functions | |
SHADebit (SHAiButtonCopr copr) | |
SHADebit constructor. | |
SHADebit (SHAiButtonCopr copr, int initialAmount, int debitAmount) | |
SHADebit constructor. | |
boolean | setupTransactionData (SHAiButtonUser user) throws OneWireException, OneWireIOException |
synchronized boolean | verifyUser (SHAiButtonUser user) throws OneWireException, OneWireIOException |
synchronized boolean | verifyTransactionData (SHAiButtonUser user) throws OneWireException, OneWireIOException |
synchronized boolean | executeTransaction (SHAiButtonUser user, boolean verifySuccess) throws OneWireException, OneWireIOException |
synchronized int | getParameter (int type) |
synchronized boolean | setParameter (int type, int param) |
synchronized void | resetParameters () |
Static Public Attributes | |
static final int | DEBIT_AMOUNT = 0 |
Update the amount this transaction will debit. | |
static final int | INITIAL_AMOUNT = 1 |
Update the amount for initial account balance. | |
static final int | USER_BALANCE = 2 |
Retrieve the amount for user's current balance. | |
static final int | I_FILE_LENGTH = 0 |
indices for fields in user account file | |
Protected Member Functions | |
SHADebit () | |
User apps should never call this. |
SHADebit | ( | SHAiButtonCopr | copr | ) |
SHADebit constructor.
copr
is the SHAiButtonCopr that is used to perform this transaction. After saving a reference to the SHA coprocessor, this constructor resets all parameters for this type of transaction to their default values.
copr | The coprocessor used for authentication and data signing in this transaction. |
SHADebit | ( | SHAiButtonCopr | copr, | |
int | initialAmount, | |||
int | debitAmount | |||
) |
SHADebit constructor.
copr
is the SHAiButtonCopr that is used to perform this transaction. After saving a reference to the SHA coprocessor, this constructor resets all parameters for this type of transaction to their default values.
copr | The coprocessor used for authentication and data signing in this transaction. |
boolean setupTransactionData | ( | SHAiButtonUser | user | ) | throws OneWireException, OneWireIOException [virtual] |
Setup account data on a fresh user iButton. Prior to calling setup transaction data, the authentication secret for the iButton should already be setup and a directory entry (as well as at least an empty placeholder file) should exist for the account data. If you constructed the SHAiButtonUser using SHAiButtonUser(SHAiButtonCopr,OneWireContainer18,boolean,byte[])
the secret has been setup for you and you should know call this function. If you try to install the authentication secret after creating the account data, you will destroy all account data on the iButton.
You can set the value of the intial account balance by calling transaction.setParameter(SHADebit.INITIAL_AMOUNT,10000)
where the value of the units is in cents (i.e. 10000 = $100).
Flow of action:
user | SHAiButtonUser upon which the transaction occurs. |
true
if and only if the signature is successfully created by the coprocessor AND the data is successfully written to the user iButton.SHAiButtonUser.writeAccountData(byte[],int)
Implements SHATransaction.
synchronized boolean verifyUser | ( | SHAiButtonUser | user | ) | throws OneWireException, OneWireIOException [virtual] |
Verifies user's authentication response. User is "authenticated" if and only if the digital signature generated the user iButton matches the digital signature generated by the coprocessor after the user's unique secret has been recreated on the coprocessor.
Flow of action:
user | SHAiButtonUser upon which the transaction occurs. |
SHAiButtonCopr.verifyAuthentication(byte[],byte[],byte[],byte[],byte)
SHAiButtonUser.readAccountData(byte[],int,byte[],int,byte[],int)
Implements SHATransaction.
synchronized boolean verifyTransactionData | ( | SHAiButtonUser | user | ) | throws OneWireException, OneWireIOException [virtual] |
Verifies user's account data. Account data is "verified" if and only if the account balance is greater than zero and the digital signature matches the signature recreated by the coprocessor.
Flow of action:
If previous steps have been executed, all "Read" commands on the user are reading from cached data.
user | SHAiButtonUser upon which the transaction occurs. |
true
if and only if the account balance is greater than zero and digital signature matches the signature recreated by the coprocessor.SHAiButtonCopr.verifySignature(byte[],byte[],byte[])
Implements SHATransaction.
synchronized boolean executeTransaction | ( | SHAiButtonUser | user, | |
boolean | verifySuccess | |||
) | throws OneWireException, OneWireIOException [virtual] |
Performs the signed debit, subtracting the debit amount from the user's balance and storing the new, signed account data on the user's iButton. The debit amount can be set using transaction.setParameter(SHADebit.DEBIT_AMOUNT, 50)
, where the value is in units of cents (i.e. for 1 dollar, use 100).
Flow of action:
If previous steps have been executed, all "Read" commands on the user are reading from cached data.
user | SHAiButtonUser upon which the transaction occurs. |
true
if and only if the user has enough in the account balance to perform the requested debit AND a new digital signature is successfully created AND the account data has been written to the button.SHAiButtonUser.writeAccountData(byte[],int)
SHAiButtonCopr.createDataSignature(byte[],byte[],byte[],int)
Implements SHATransaction.
synchronized int getParameter | ( | int | type | ) | [virtual] |
Retrieves the value of a particular parameter for this debit transaction.
Valid Parameters
Note that the value of SHADebit.USER_BALANCE
will be set after calling verifyTransactionData(SHAiButtonUser)
and after calling executeTransaction(SHAiButtonUser)
.
IllegalArgumentException | if an invalid parameter type is requested. |
Implements SHATransaction.
synchronized boolean setParameter | ( | int | type, | |
int | param | |||
) | [virtual] |
Sets the value of a particular parameter for this debit transaction.
Valid Parameters
type | Specifies the parameter type (SHADebit.DEBIT_AMOUNT or SHADebit.INITIAL_AMOUNT ) |
IllegalArgumentException | if an invalid parameter type is requested. |
Implements SHATransaction.
synchronized void resetParameters | ( | ) | [virtual] |
Resets all transaction parameters to default values
Implements SHATransaction.