| java.lang.Object
 com.sun.midp.crypto.MessageDigest
All known Subclasses: com.sun.midp.crypto.MD5, com.sun.midp.crypto.MD2, com.sun.midp.crypto.SHA,
| MessageDigest | | abstract public class MessageDigest (Code) | | This MessageDigest class provides applications the functionality of a
message digest algorithm, such as MD5 or SHA.
Message digests are secure one-way hash functions that take arbitrary-sized
data and output a fixed-length hash value.
A MessageDigest object starts out initialized. The data is
processed through it using the update
method. At any point
MessageDigest.reset() reset can be called
to reset the digest. Once all the data to be updated has been
updated, the digest method should
be called to complete the hash computation.
The digest method can be called once for a given number
of updates. After digest has been called,
the MessageDigest
object is reset to its initialized state.
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| Constructor Summary | |
| protected | MessageDigest()
Protected constructor. |
| Method Summary | |
| abstract public Object | clone()
Clones the MessageDigest object. | | abstract public int | digest(byte[] buf, int offset, int len)
Completes the hash computation by performing final operations
such as padding. | | abstract public String | getAlgorithm()
Gets the message digest algorithm. | | abstract public int | getDigestLength()
Gets the length (in bytes) of the hash. | | public static MessageDigest | getInstance(String algorithm)
Generates a MessageDigest object that implements
the specified digest
algorithm. | | abstract public void | reset()
Resets the MessageDigest to the initial state for further use. | | abstract public void | update(byte[] inBuf, int inOff, int inLen)
Accumulates a hash of the input data. |
| MessageDigest | | protected MessageDigest()(Code) | | Protected constructor.
|
| clone | | abstract public Object clone()(Code) | | Clones the MessageDigest object.
a clone of this object |
| digest | | abstract public int digest(byte[] buf, int offset, int len) throws DigestException(Code) | | Completes the hash computation by performing final operations
such as padding. The digest is reset after this call is made.
Parameters:
buf - output buffer for the computed digest
Parameters:
offset - offset into the output buffer to begin storing the digest
Parameters:
len - number of bytes within buf allotted for the digest the number of bytes placed into buf
exception:
DigestException - if an error occurs. |
| getAlgorithm | | abstract public String getAlgorithm()(Code) | | Gets the message digest algorithm.
algorithm implemented by this MessageDigest object |
| getDigestLength | | abstract public int getDigestLength()(Code) | | Gets the length (in bytes) of the hash.
byte-length of the hash produced by this object |
| getInstance | | public static MessageDigest getInstance(String algorithm) throws NoSuchAlgorithmException(Code) | | Generates a MessageDigest object that implements
the specified digest
algorithm.
Parameters:
algorithm - the name of the algorithm requested. See Appendix A in the Java Cryptography Architecture API Specification & Referencefor information about standard algorithm names. a MessageDigest object implementing the specifiedalgorithm.
exception:
NoSuchAlgorithmException - if the algorithm isnot available in the caller's environment. |
| reset | | abstract public void reset()(Code) | | Resets the MessageDigest to the initial state for further use.
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| update | | abstract public void update(byte[] inBuf, int inOff, int inLen)(Code) | | Accumulates a hash of the input data. This method is useful when
the input data to be hashed is not available in one byte array.
Parameters:
inBuf - input buffer of data to be hashed
Parameters:
inOff - offset within inBuf where input data begins
Parameters:
inLen - length (in bytes) of data to be hashed
See Also: MessageDigest.doFinal(byte[],int,int,byte[],int) |
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