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JavaTM 2 Platform Standard Ed. 5.0 |
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java.lang.Objectjavax.crypto.spec.SecretKeySpec
public class SecretKeySpec
This class specifies a secret key in a provider-independent fashion.
It can be used to construct a SecretKey
from a byte array,
without having to go through a (provider-based)
SecretKeyFactory
.
This class is only useful for raw secret keys that can be represented as a byte array and have no key parameters associated with them, e.g., DES or Triple DES keys.
SecretKey
,
SecretKeyFactory
,
Serialized FormField Summary |
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Fields inherited from interface javax.crypto.SecretKey |
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serialVersionUID |
Constructor Summary | |
---|---|
SecretKeySpec(byte[] key,
int offset,
int len,
String algorithm)
Constructs a secret key from the given byte array, using the first len bytes of key , starting at
offset inclusive. |
|
SecretKeySpec(byte[] key,
String algorithm)
Constructs a secret key from the given byte array. |
Method Summary | |
---|---|
boolean |
equals(Object obj)
Tests for equality between the specified object and this object. |
String |
getAlgorithm()
Returns the name of the algorithm associated with this secret key. |
byte[] |
getEncoded()
Returns the key material of this secret key. |
String |
getFormat()
Returns the name of the encoding format for this secret key. |
int |
hashCode()
Calculates a hash code value for the object. |
Methods inherited from class java.lang.Object |
---|
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public SecretKeySpec(byte[] key, String algorithm)
This constructor does not check if the given bytes indeed specify a
secret key of the specified algorithm. For example, if the algorithm is
DES, this constructor does not check if key
is 8 bytes
long, and also does not check for weak or semi-weak keys.
In order for those checks to be performed, an algorithm-specific
key specification class (in this case:
DESKeySpec
)
should be used.
key
- the key material of the secret key. The contents of
the array are copied to protect against subsequent modification.algorithm
- the name of the secret-key algorithm to be associated
with the given key material.
See Appendix A in the
Java Cryptography Extension Reference Guide
for information about standard algorithm names.
IllegalArgumentException
- if algorithm
is null or key
is null or empty.public SecretKeySpec(byte[] key, int offset, int len, String algorithm)
len
bytes of key
, starting at
offset
inclusive.
The bytes that constitute the secret key are
those between key[offset]
and
key[offset+len-1]
inclusive.
This constructor does not check if the given bytes indeed specify a
secret key of the specified algorithm. For example, if the algorithm is
DES, this constructor does not check if key
is 8 bytes
long, and also does not check for weak or semi-weak keys.
In order for those checks to be performed, an algorithm-specific key
specification class (in this case:
DESKeySpec
)
must be used.
key
- the key material of the secret key. The first
len
bytes of the array beginning at
offset
inclusive are copied to protect
against subsequent modification.offset
- the offset in key
where the key material
starts.len
- the length of the key material.algorithm
- the name of the secret-key algorithm to be associated
with the given key material.
See Appendix A in the
Java Cryptography Extension Reference Guide
for information about standard algorithm names.
IllegalArgumentException
- if algorithm
is null or key
is null, empty, or too short,
i.e. key.length-offset.
ArrayIndexOutOfBoundsException
- is thrown if
offset
or len
index bytes outside the
key
.
Method Detail
getAlgorithm
public String getAlgorithm()
- Returns the name of the algorithm associated with this secret key.
- Specified by:
getAlgorithm
in interface Key
- Returns:
- the secret key algorithm.
getFormat
public String getFormat()
- Returns the name of the encoding format for this secret key.
- Specified by:
getFormat
in interface Key
- Returns:
- the string "RAW".
getEncoded
public byte[] getEncoded()
- Returns the key material of this secret key.
- Specified by:
getEncoded
in interface Key
- Returns:
- the key material. Returns a new array
each time this method is called.
hashCode
public int hashCode()
- Calculates a hash code value for the object.
Objects that are equal will also have the same hashcode.
- Overrides:
hashCode
in class Object
- Returns:
- a hash code value for this object.
- See Also:
Object.equals(java.lang.Object)
,
Hashtable
equals
public boolean equals(Object obj)
- Tests for equality between the specified object and this
object. Two SecretKeySpec objects are considered equal if
they are both SecretKey instances which have the
same case-insensitive algorithm name and key encoding.
- Overrides:
equals
in class Object
- Parameters:
obj
- the object to test for equality with this object.
- Returns:
- true if the objects are considered equal, false if
obj
is null or otherwise. - See Also:
Object.hashCode()
,
Hashtable
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.