public interface SignatureMessageRecovery
Signature
class must implement this
SignatureMessageRecovery
interface to provide message recovery
functionality. An instance implementing this interface is returned by the
Signature.getInstance(byte, boolean)
method when algorithm type with suffix *_MR
is specified. e.g.Signature.ALG_RSA_SHA_ISO9796_MR
.
This interface provides specialized versions of some of the methods defined
in the Signature
class to provide message recovery functions.
An alternate version of the sign()
and verify()
methods is supported here along with a new beginVerify
method
to allow the message encoded in the signature to be recovered.
For signing a message with message recovery functionality, the user must cast
the Signature
object to this interface, initialize the object
for signing with a private key using the init()
method, and
issue 0 or more update()
method calls and then finally call
the sign()
method to obtain the signature.
For recovering the encoded message and verifying functionality, the user must
cast the Signature
object to this interface, initialize the
object for verifying with a public key using the init()
method, first recover the message using the beginVerify()
method and then issue 0 or more update()
method calls and then
finally call the verify()
method to verify the signature.
Note:
A Signature
object implementing this interface must throw
CryptoException
with CryptoException.ILLEGAL_USE
reason code when one of the following methods applicable only to a
Signature
object which does not include message recovery
functionality, is called:
Modifier and Type | Method and Description |
---|---|
short |
beginVerify(byte[] sigAndRecDataBuff,
short buffOffset,
short sigLength)
This method begins the verification sequence by recovering the message
encoded within the signature itself and initializing the internal hash
function.
|
byte |
getAlgorithm()
Gets the Signature algorithm.
|
short |
getLength()
Returns the byte length of the signature data.
|
void |
init(Key theKey,
byte theMode)
Initializes the
Signature object with the appropriate
Key . |
short |
sign(byte[] inBuff,
short inOffset,
short inLength,
byte[] sigBuff,
short sigOffset,
short[] recMsgLen,
short recMsgLenOffset)
Generates the signature of all/last input data.
|
void |
update(byte[] inBuff,
short inOffset,
short inLength)
Accumulates a signature of the input data.
|
boolean |
verify(byte[] inBuff,
short inOffset,
short inLength)
Verifies the signature of all/last input data against the passed in
signature.
|
void init(Key theKey, byte theMode) throws CryptoException
Signature
object with the appropriate
Key
. This method should be used for algorithms which do
not need initialization parameters or use default parameter values.
init()
must be used to update the Signature
object with a new key. If the Key
object is modified after
invoking the init()
method, the behavior of the
update()
, sign()
, and
verify()
methods is unspecified.
theKey
- the key object to use for signing or verifyingtheMode
- one of MODE_SIGN
or MODE_VERIFY
CryptoException
- with the following reason codes:
CryptoException.ILLEGAL_VALUE
if
theMode
option is an undefined value or if
the Key
is inconsistent with
theMode
or with the Signature
implementation.
CryptoException.UNINITIALIZED_KEY
if
theKey
instance is uninitialized.
short beginVerify(byte[] sigAndRecDataBuff, short buffOffset, short sigLength) throws CryptoException
sigAndRecDataBuff
input byte array.
Notes:
update()
or the verify()
methods during verification.
sigLength
- recovered message length) bytes of
signature data in sigAndRecDataBuff
may also be overwritten
by this method.
sigAndRecDataBuff
- contains the signature data as input and also contains the
recoverable part of the message as output.buffOffset
- offset into the sigAndRecDataBuff array where data begins for
signature and where this method will start writing recovered
message data.sigLength
- the length of signature datasigAndRecDataBuff
CryptoException
- with the following reason codes:
CryptoException.ILLEGAL_USE
for the
following conditions:
sigLength
is inconsistent with this
Signature
algorithm
CryptoException.UNINITIALIZED_KEY
if
key not initialized.
CryptoException.INVALID_INIT
if this
Signature
object is not initialized.
short sign(byte[] inBuff, short inOffset, short inLength, byte[] sigBuff, short sigOffset, short[] recMsgLen, short recMsgLenOffset) throws CryptoException
A call to this method also resets this Signature
object to
the state it was in when previously initialized via a call to
init()
. That is, the object is reset and available to
sign another message.
The input and output buffer data may overlap.
inBuff
- the input buffer of data to be signedinOffset
- the offset into the input buffer at which to begin signature
generationinLength
- the byte length to signsigBuff
- the output buffer to store signature datasigOffset
- the offset into sigBuff at which to begin signature datarecMsgLen
- the output buffer containing the number of bytes of the
recoverable message beginning with the first byte of the
message that was encoded into the signature itselfrecMsgLenOffset
- offset into the recMsgLen
output buffer where
the byte length of the recoverable message is stored. Note
that a single short value is stored at
recMsgLenOffset
offset.CryptoException
- with the following reason codes:
CryptoException.UNINITIALIZED_KEY
if
key not initialized.
CryptoException.INVALID_INIT
if this
Signature
object is not initialized or
initialized for signature verify mode.
boolean verify(byte[] inBuff, short inOffset, short inLength) throws CryptoException
A call to this method also resets this Signature
object to
the state it was in when previously initialized via a call to
init()
. That is, the object is reset and available to
verify another message.
inBuff
- the input buffer of data to be verifiedinOffset
- the offset into the input buffer at which to begin signature
generationinLength
- the byte length to signtrue
if the signature verifies, false
otherwiseCryptoException
- with the following reason codes:
CryptoException.UNINITIALIZED_KEY
if
key not initialized.
CryptoException.INVALID_INIT
if this
Signature
object is not initialized or
initialized for signature sign mode.
CryptoException.ILLEGAL_USE
if one of
the following conditions is met:
beginVerify
method has not been
called.
byte getAlgorithm()
Signature
instance.short getLength() throws CryptoException
CryptoException
- with the following reason codes:
CryptoException.INVALID_INIT
if this
Signature
object is not initialized.
CryptoException.UNINITIALIZED_KEY
if
key not initialized.
void update(byte[] inBuff, short inOffset, short inLength) throws CryptoException
sign()
or beginVerify
method and verify()
method is recommended. The
sign()
or verify()
method must be called to
complete processing of input data accumulated by one or more calls to the
update()
method.
Note:
inLength
is 0 this method does nothing.
inBuff
- the input buffer of data to be signed/verifiedinOffset
- the offset into the input buffer where input data beginsinLength
- the byte length to sign/verifyCryptoException
- with the following reason codes:
CryptoException.UNINITIALIZED_KEY
if
key not initialized.
CryptoException.INVALID_INIT
if this
Signature
object is not initialized.
CryptoException.ILLEGAL_USE
if the
mode set in the init()
method is
MODE_VERIFY and the beginVerify()
method is
not yet called.
sign(byte[], short, short, byte[], short, short[], short)
,
verify(byte[], short, short)
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