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package javax.crypto.spec;
import java.security.MessageDigest;
import java.security.spec.KeySpec;
import java.util.Locale;
import javax.crypto.SecretKey;
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.
Author: Jan Luehe See Also: Since: 1.4
/**
* This class specifies a secret key in a provider-independent fashion.
*
* <p>It can be used to construct a <code>SecretKey</code> from a byte array,
* without having to go through a (provider-based)
* <code>SecretKeyFactory</code>.
*
* <p>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.
*
* @author Jan Luehe
*
* @see javax.crypto.SecretKey
* @see javax.crypto.SecretKeyFactory
* @since 1.4
*/
public class SecretKeySpec implements KeySpec, SecretKey {
private static final long serialVersionUID = 6577238317307289933L;
The secret key.
@serial
/**
* The secret key.
*
* @serial
*/
private byte[] key;
The name of the algorithm associated with this key.
@serial
/**
* The name of the algorithm associated with this key.
*
* @serial
*/
private String algorithm;
Constructs a secret key from the given byte array.
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.
Params: - 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 the
Java Security Standard Algorithm Names document
for information about standard algorithm names.
Throws: - IllegalArgumentException – if
algorithm
is null or key is null or empty.
/**
* Constructs a secret key from the given byte array.
*
* <p>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 <code>key</code> 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
* <i>key specification</i> class (in this case:
* {@link DESKeySpec DESKeySpec})
* should be used.
*
* @param key the key material of the secret key. The contents of
* the array are copied to protect against subsequent modification.
* @param algorithm the name of the secret-key algorithm to be associated
* with the given key material.
* See the <a href="{@docRoot}/../specs/security/standard-names.html">
* Java Security Standard Algorithm Names</a> document
* for information about standard algorithm names.
* @exception IllegalArgumentException if <code>algorithm</code>
* is null or <code>key</code> is null or empty.
*/
public SecretKeySpec(byte[] key, String algorithm) {
if (key == null || algorithm == null) {
throw new IllegalArgumentException("Missing argument");
}
if (key.length == 0) {
throw new IllegalArgumentException("Empty key");
}
this.key = key.clone();
this.algorithm = algorithm;
}
Constructs a secret key from the given byte array, using the first
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.
Params: - 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 the
Java Security Standard Algorithm Names document
for information about standard algorithm names.
Throws: - IllegalArgumentException – if
algorithm
is null or key is null, empty, or too short, i.e. key.length-offset<len. - ArrayIndexOutOfBoundsException – is thrown if
offset or len index bytes outside the
key.
/**
* Constructs a secret key from the given byte array, using the first
* <code>len</code> bytes of <code>key</code>, starting at
* <code>offset</code> inclusive.
*
* <p> The bytes that constitute the secret key are
* those between <code>key[offset]</code> and
* <code>key[offset+len-1]</code> inclusive.
*
* <p>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 <code>key</code> 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:
* {@link DESKeySpec DESKeySpec})
* must be used.
*
* @param key the key material of the secret key. The first
* <code>len</code> bytes of the array beginning at
* <code>offset</code> inclusive are copied to protect
* against subsequent modification.
* @param offset the offset in <code>key</code> where the key material
* starts.
* @param len the length of the key material.
* @param algorithm the name of the secret-key algorithm to be associated
* with the given key material.
* See the <a href="{@docRoot}/../specs/security/standard-names.html">
* Java Security Standard Algorithm Names</a> document
* for information about standard algorithm names.
* @exception IllegalArgumentException if <code>algorithm</code>
* is null or <code>key</code> is null, empty, or too short,
* i.e. {@code key.length-offset<len}.
* @exception ArrayIndexOutOfBoundsException is thrown if
* <code>offset</code> or <code>len</code> index bytes outside the
* <code>key</code>.
*/
public SecretKeySpec(byte[] key, int offset, int len, String algorithm) {
if (key == null || algorithm == null) {
throw new IllegalArgumentException("Missing argument");
}
if (key.length == 0) {
throw new IllegalArgumentException("Empty key");
}
if (key.length-offset < len) {
throw new IllegalArgumentException
("Invalid offset/length combination");
}
if (len < 0) {
throw new ArrayIndexOutOfBoundsException("len is negative");
}
this.key = new byte[len];
System.arraycopy(key, offset, this.key, 0, len);
this.algorithm = algorithm;
}
Returns the name of the algorithm associated with this secret key.
Returns: the secret key algorithm.
/**
* Returns the name of the algorithm associated with this secret key.
*
* @return the secret key algorithm.
*/
public String getAlgorithm() {
return this.algorithm;
}
Returns the name of the encoding format for this secret key.
Returns: the string "RAW".
/**
* Returns the name of the encoding format for this secret key.
*
* @return the string "RAW".
*/
public String getFormat() {
return "RAW";
}
Returns the key material of this secret key.
Returns: the key material. Returns a new array
each time this method is called.
/**
* Returns the key material of this secret key.
*
* @return the key material. Returns a new array
* each time this method is called.
*/
public byte[] getEncoded() {
return this.key.clone();
}
Calculates a hash code value for the object.
Objects that are equal will also have the same hashcode.
/**
* Calculates a hash code value for the object.
* Objects that are equal will also have the same hashcode.
*/
public int hashCode() {
int retval = 0;
for (int i = 1; i < this.key.length; i++) {
retval += this.key[i] * i;
}
if (this.algorithm.equalsIgnoreCase("TripleDES"))
return (retval ^= "desede".hashCode());
else
return (retval ^=
this.algorithm.toLowerCase(Locale.ENGLISH).hashCode());
}
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.
Params: - 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.
/**
* 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.
*
* @param obj the object to test for equality with this object.
*
* @return true if the objects are considered equal, false if
* <code>obj</code> is null or otherwise.
*/
public boolean equals(Object obj) {
if (this == obj)
return true;
if (!(obj instanceof SecretKey))
return false;
String thatAlg = ((SecretKey)obj).getAlgorithm();
if (!(thatAlg.equalsIgnoreCase(this.algorithm))) {
if ((!(thatAlg.equalsIgnoreCase("DESede"))
|| !(this.algorithm.equalsIgnoreCase("TripleDES")))
&& (!(thatAlg.equalsIgnoreCase("TripleDES"))
|| !(this.algorithm.equalsIgnoreCase("DESede"))))
return false;
}
byte[] thatKey = ((SecretKey)obj).getEncoded();
return MessageDigest.isEqual(this.key, thatKey);
}
}