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JavaTM 2 Platform Std. Ed. v1.5.0
java.security
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Constructor Summary | |
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protected |
MessageDigest(String algorithm)
Creates a message digest with the specified algorithm name. |
Method Summary | |
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Object |
clone()
Returns a clone if the implementation is cloneable. |
byte[] |
digest()
Completes the hash computation by performing final operations such as padding. |
byte[] |
digest(byte[] input)
Performs a final update on the digest using the specified array of bytes, then completes the digest computation. |
int |
digest(byte[] buf,
int offset,
int len)
Completes the hash computation by performing final operations such as padding. |
String |
getAlgorithm()
Returns a string that identifies the algorithm, independent of implementation details. |
int |
getDigestLength()
Returns the length of the digest in bytes, or 0 if this operation is not supported by the provider and the implementation is not cloneable. |
static MessageDigest |
getInstance(String algorithm)
Generates a MessageDigest object that implements the specified digest algorithm. |
static MessageDigest |
getInstance(String algorithm,
Provider provider)
Generates a MessageDigest object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider. |
static MessageDigest |
getInstance(String algorithm,
String provider)
Generates a MessageDigest object implementing the specified algorithm, as supplied from the specified provider, if such an algorithm is available from the provider. |
Provider |
getProvider()
Returns the provider of this message digest object. |
static boolean |
isEqual(byte[] digesta,
byte[] digestb)
Compares two digests for equality. |
void |
reset()
Resets the digest for further use. |
String |
toString()
Returns a string representation of this message digest object. |
void |
update(byte input)
Updates the digest using the specified byte. |
void |
update(byte[] input)
Updates the digest using the specified array of bytes. |
void |
update(byte[] input,
int offset,
int len)
Updates the digest using the specified array of bytes, starting at the specified offset. |
void |
update(ByteBuffer input)
Update the digest using the specified ByteBuffer. |
Methods inherited from class java.security.MessageDigestSpi |
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engineDigest, engineDigest, engineGetDigestLength, engineReset, engineUpdate, engineUpdate, engineUpdate |
Methods inherited from class java.lang.Object |
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equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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protected MessageDigest(String algorithm)
algorithm
- the standard name of the digest algorithm.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.Method Detail |
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public static MessageDigest getInstance(String algorithm) throws NoSuchAlgorithmException
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.
NoSuchAlgorithmException
- if the algorithm is
not available in the caller's environment.public static MessageDigest getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.provider
- the name of the provider.
NoSuchAlgorithmException
- if the algorithm is
not available in the package supplied by the requested
provider.
NoSuchProviderException
- if the provider is not
available in the environment.
IllegalArgumentException
- if the provider name is null
or empty.Provider
public static MessageDigest getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException
provider
doesn't have to be registered.
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.provider
- the provider.
NoSuchAlgorithmException
- if the algorithm is
not available in the package supplied by the requested
provider.
IllegalArgumentException
- if the provider
is
null.Provider
public final Provider getProvider()
public void update(byte input)
input
- the byte with which to update the digest.public void update(byte[] input, int offset, int len)
input
- the array of bytes.offset
- the offset to start from in the array of bytes.len
- the number of bytes to use, starting at
offset
.public void update(byte[] input)
input
- the array of bytes.public final void update(ByteBuffer input)
input.remaining()
bytes starting
at input.position()
.
Upon return, the buffer's position will be equal to its limit;
its limit will not have changed.
input
- the ByteBufferpublic byte[] digest()
public int digest(byte[] buf, int offset, int len) throws DigestException
buf
- output buffer for the computed digestoffset
- offset into the output buffer to begin storing the digestlen
- number of bytes within buf allotted for the digest
buf
DigestException
- if an error occurs.public byte[] digest(byte[] input)
update(input)
,
passing the input array to the update
method,
then calls digest()
.
input
- the input to be updated before the digest is
completed.
public String toString()
public static boolean isEqual(byte[] digesta, byte[] digestb)
digesta
- one of the digests to compare.digestb
- the other digest to compare.
public void reset()
public final String getAlgorithm()
public final int getDigestLength()
public Object clone() throws CloneNotSupportedException
clone
in class MessageDigestSpi
CloneNotSupportedException
- if this is called on an
implementation that does not support Cloneable
.Cloneable