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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package javax.crypto;

import java.security.*;
import java.security.spec.AlgorithmParameterSpec;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.Vector;

import javax.crypto.spec.*;


The CryptoPermission class extends the
java.security.Permission class. A
CryptoPermission object is used to represent
the ability of an application/applet to use certain
algorithms with certain key sizes and other
restrictions in certain environments. 


Author:Jan Luehe, Sharon Liu
See Also:
  • Permission
Since:1.4
/**
 * The CryptoPermission class extends the
 * java.security.Permission class. A
 * CryptoPermission object is used to represent
 * the ability of an application/applet to use certain
 * algorithms with certain key sizes and other
 * restrictions in certain environments. <p>
 *
 * @see java.security.Permission
 *
 * @author Jan Luehe
 * @author Sharon Liu
 * @since 1.4
 */
class CryptoPermission extends java.security.Permission {

    private static final long serialVersionUID = 8987399626114087514L;

    private String alg;
    private int maxKeySize = Integer.MAX_VALUE; // no restriction on maxKeySize
    private String exemptionMechanism = null;
    private AlgorithmParameterSpec algParamSpec = null;
    private boolean checkParam = false; // no restriction on param

    static final String ALG_NAME_WILDCARD = "*";

    
Constructor that takes an algorithm name.
This constructor implies that the given algorithm can be
used without any restrictions.

Params:
  • alg – the algorithm name.
/**
     * Constructor that takes an algorithm name.
     *
     * This constructor implies that the given algorithm can be
     * used without any restrictions.
     *
     * @param alg the algorithm name.
     */
    CryptoPermission(String alg) {
        super(null);
        this.alg = alg;
    }

    
Constructor that takes an algorithm name and a maximum
key size.
This constructor implies that the given algorithm can be
used with a key size up to maxKeySize.

Params:
  • alg – the algorithm name.
  • maxKeySize – the maximum allowable key size,
specified in number of bits.
/**
     * Constructor that takes an algorithm name and a maximum
     * key size.
     *
     * This constructor implies that the given algorithm can be
     * used with a key size up to <code>maxKeySize</code>.
     *
     * @param alg the algorithm name.
     *
     * @param maxKeySize the maximum allowable key size,
     * specified in number of bits.
     */
    CryptoPermission(String alg, int maxKeySize) {
        super(null);
        this.alg = alg;
        this.maxKeySize = maxKeySize;
    }

    
Constructor that takes an algorithm name, a maximum
key size, and an AlgorithmParameterSpec object.
This constructor implies that the given algorithm can be
used with a key size up to maxKeySize, and
algorithm
parameters up to the limits set in algParamSpec.

Params:
  • alg – the algorithm name.
  • maxKeySize – the maximum allowable key size,
specified in number of bits.
  • algParamSpec – the limits for allowable algorithm
parameters.
/**
     * Constructor that takes an algorithm name, a maximum
     * key size, and an AlgorithmParameterSpec object.
     *
     * This constructor implies that the given algorithm can be
     * used with a key size up to <code>maxKeySize</code>, and
     * algorithm
     * parameters up to the limits set in <code>algParamSpec</code>.
     *
     * @param alg the algorithm name.
     *
     * @param maxKeySize the maximum allowable key size,
     * specified in number of bits.
     *
     * @param algParamSpec the limits for allowable algorithm
     * parameters.
     */
    CryptoPermission(String alg,
                     int maxKeySize,
                     AlgorithmParameterSpec algParamSpec) {
        super(null);
        this.alg = alg;
        this.maxKeySize = maxKeySize;
        this.checkParam = true;
        this.algParamSpec = algParamSpec;
    }

    
Constructor that takes an algorithm name and the name of
an exemption mechanism.
This constructor implies that the given algorithm can be
used without any key size or algorithm parameter restrictions
provided that the specified exemption mechanism is enforced.

Params:
  • alg – the algorithm name.
  • exemptionMechanism – the name of the exemption mechanism.
/**
     * Constructor that takes an algorithm name and the name of
     * an exemption mechanism.
     *
     * This constructor implies that the given algorithm can be
     * used without any key size or algorithm parameter restrictions
     * provided that the specified exemption mechanism is enforced.
     *
     * @param alg the algorithm name.
     *
     * @param exemptionMechanism the name of the exemption mechanism.
     */
    CryptoPermission(String alg,
                     String exemptionMechanism) {
        super(null);
        this.alg = alg;
        this.exemptionMechanism = exemptionMechanism;
    }

    
Constructor that takes an algorithm name, a maximum key
size, and the name of an exemption mechanism.
This constructor implies that the given algorithm can be
used with a key size up to maxKeySize
provided that the
specified exemption mechanism is enforced.

Params:
  • alg – the algorithm name.
  • maxKeySize – the maximum allowable key size,
specified in number of bits.
  • exemptionMechanism – the name of the exemption
mechanism.
/**
     * Constructor that takes an algorithm name, a maximum key
     * size, and the name of an exemption mechanism.
     *
     * This constructor implies that the given algorithm can be
     * used with a key size up to <code>maxKeySize</code>
     * provided that the
     * specified exemption mechanism is enforced.
     *
     * @param alg the algorithm name.
     * @param maxKeySize the maximum allowable key size,
     * specified in number of bits.
     * @param exemptionMechanism the name of the exemption
     * mechanism.
     */
    CryptoPermission(String alg,
                     int maxKeySize,
                     String exemptionMechanism) {
        super(null);
        this.alg = alg;
        this.exemptionMechanism = exemptionMechanism;
        this.maxKeySize = maxKeySize;
    }

    
Constructor that takes an algorithm name, a maximum key
size, the name of an exemption mechanism, and an
AlgorithmParameterSpec object.
This constructor implies that the given algorithm can be
used with a key size up to maxKeySize
and algorithm
parameters up to the limits set in algParamSpec
provided that
the specified exemption mechanism is enforced.

Params:
  • alg – the algorithm name.
  • maxKeySize – the maximum allowable key size,
specified in number of bits.
  • algParamSpec – the limit for allowable algorithm
 parameter spec.
  • exemptionMechanism – the name of the exemption
mechanism.
/**
     * Constructor that takes an algorithm name, a maximum key
     * size, the name of an exemption mechanism, and an
     * AlgorithmParameterSpec object.
     *
     * This constructor implies that the given algorithm can be
     * used with a key size up to <code>maxKeySize</code>
     * and algorithm
     * parameters up to the limits set in <code>algParamSpec</code>
     * provided that
     * the specified exemption mechanism is enforced.
     *
     * @param alg the algorithm name.
     * @param maxKeySize the maximum allowable key size,
     * specified in number of bits.
     * @param algParamSpec the limit for allowable algorithm
     *  parameter spec.
     * @param exemptionMechanism the name of the exemption
     * mechanism.
     */
    CryptoPermission(String alg,
                     int maxKeySize,
                     AlgorithmParameterSpec algParamSpec,
                     String exemptionMechanism) {
        super(null);
        this.alg = alg;
        this.exemptionMechanism = exemptionMechanism;
        this.maxKeySize = maxKeySize;
        this.checkParam = true;
        this.algParamSpec = algParamSpec;
    }

    
Checks if the specified permission is "implied" by
this object.


More specifically, this method returns true if:


    

  •  p is an instance of CryptoPermission, and
    

  •  p's algorithm name equals or (in the case of wildcards)
      is implied by this permission's algorithm name, and
    

  •  p's maximum allowable key size is less or
      equal to this permission's maximum allowable key size, and
    

  •  p's algorithm parameter spec equals or is
       implied by this permission's algorithm parameter spec, and
    

  •  p's exemptionMechanism equals or
       is implied by this permission's
       exemptionMechanism (a null exemption mechanism
       implies any other exemption mechanism).



Params:
  • p – the permission to check against.
Returns:true if the specified permission is equal to or
implied by this permission, false otherwise.
/**
     * Checks if the specified permission is "implied" by
     * this object.
     * <p>
     * More specifically, this method returns true if:<p>
     * <ul>
     * <li> <i>p</i> is an instance of CryptoPermission, and<p>
     * <li> <i>p</i>'s algorithm name equals or (in the case of wildcards)
     *       is implied by this permission's algorithm name, and<p>
     * <li> <i>p</i>'s maximum allowable key size is less or
     *       equal to this permission's maximum allowable key size, and<p>
     * <li> <i>p</i>'s algorithm parameter spec equals or is
     *        implied by this permission's algorithm parameter spec, and<p>
     * <li> <i>p</i>'s exemptionMechanism equals or
     *        is implied by this permission's
     *        exemptionMechanism (a <code>null</code> exemption mechanism
     *        implies any other exemption mechanism).
     * </ul>
     *
     * @param p the permission to check against.
     *
     * @return true if the specified permission is equal to or
     * implied by this permission, false otherwise.
     */
    public boolean implies(Permission p) {
        if (!(p instanceof CryptoPermission))
            return false;

        CryptoPermission cp = (CryptoPermission)p;

        if ((!alg.equalsIgnoreCase(cp.alg)) &&
            (!alg.equalsIgnoreCase(ALG_NAME_WILDCARD))) {
            return false;
        }

        // alg is the same as cp's alg or
        // alg is a wildcard.
        if (cp.maxKeySize <= this.maxKeySize) {
            // check algParamSpec.
            if (!impliesParameterSpec(cp.checkParam, cp.algParamSpec)) {
                return false;
            }

            // check exemptionMechanism.
            if (impliesExemptionMechanism(cp.exemptionMechanism)) {
                return true;
            }
        }

        return false;
    }

    
Checks two CryptoPermission objects for equality. Checks that
obj is a CryptoPermission, and has the same
algorithm name,
exemption mechanism name, maximum allowable key size and
algorithm parameter spec
as this object.



Params:
  • obj – the object to test for equality with this object.
Returns:true if obj is equal to this object.
/**
     * Checks two CryptoPermission objects for equality. Checks that
     * <code>obj</code> is a CryptoPermission, and has the same
     * algorithm name,
     * exemption mechanism name, maximum allowable key size and
     * algorithm parameter spec
     * as this object.
     * <P>
     * @param obj the object to test for equality with this object.
     * @return true if <code>obj</code> is equal to this object.
     */
    public boolean equals(Object obj) {
        if (obj == this)
            return true;

        if (!(obj instanceof CryptoPermission))
            return false;

        CryptoPermission that = (CryptoPermission) obj;

        if (!(alg.equalsIgnoreCase(that.alg)) ||
            (maxKeySize != that.maxKeySize)) {
            return false;
        }
        if (this.checkParam != that.checkParam) {
            return false;
        }
        return (equalObjects(this.exemptionMechanism,
                             that.exemptionMechanism) &&
                equalObjects(this.algParamSpec,
                             that.algParamSpec));
    }

    
Returns the hash code value for this object.

Returns:a hash code value for this object.
/**
     * Returns the hash code value for this object.
     *
     * @return a hash code value for this object.
     */

    public int hashCode() {
        int retval = alg.hashCode();
        retval ^= maxKeySize;
        if (exemptionMechanism != null) {
            retval ^= exemptionMechanism.hashCode();
        }
        if (checkParam) retval ^= 100;
        if (algParamSpec != null) {
            retval ^= algParamSpec.hashCode();
        }
        return retval;
    }

    
There is no action defined for a CryptoPermission
onject.

/**
     * There is no action defined for a CryptoPermission
     * onject.
     */
    public String getActions()
    {
        return null;
    }

    
Returns a new PermissionCollection object for storing
CryptoPermission objects.

Returns:a new PermissionCollection object suitable for storing
CryptoPermissions.
/**
     * Returns a new PermissionCollection object for storing
     * CryptoPermission objects.
     *
     * @return a new PermissionCollection object suitable for storing
     * CryptoPermissions.
     */

    public PermissionCollection newPermissionCollection() {
        return new CryptoPermissionCollection();
    }

    
Returns the algorithm name associated with
this CryptoPermission object.

/**
     * Returns the algorithm name associated with
     * this CryptoPermission object.
     */
    final String getAlgorithm() {
        return alg;
    }

    
Returns the exemption mechanism name
associated with this CryptoPermission
object.

/**
     * Returns the exemption mechanism name
     * associated with this CryptoPermission
     * object.
     */
    final String getExemptionMechanism() {
        return exemptionMechanism;
    }

    
Returns the maximum allowable key size associated
with this CryptoPermission object.

/**
     * Returns the maximum allowable key size associated
     * with this CryptoPermission object.
     */
    final int getMaxKeySize() {
        return maxKeySize;
    }

    
Returns true if there is a limitation on the
AlgorithmParameterSpec associated with this
CryptoPermission object and false if otherwise.

/**
     * Returns true if there is a limitation on the
     * AlgorithmParameterSpec associated with this
     * CryptoPermission object and false if otherwise.
     */
    final boolean getCheckParam() {
        return checkParam;
    }

    
Returns the AlgorithmParameterSpec
associated with this CryptoPermission
object.

/**
     * Returns the AlgorithmParameterSpec
     * associated with this CryptoPermission
     * object.
     */
    final AlgorithmParameterSpec getAlgorithmParameterSpec() {
        return algParamSpec;
    }

    
Returns a string describing this CryptoPermission.  The convention is to
specify the class name, the algorithm name, the maximum allowable
key size, and the name of the exemption mechanism, in the following
format: '("ClassName" "algorithm" "keysize" "exemption_mechanism")'.

Returns:information about this CryptoPermission.
/**
     * Returns a string describing this CryptoPermission.  The convention is to
     * specify the class name, the algorithm name, the maximum allowable
     * key size, and the name of the exemption mechanism, in the following
     * format: '("ClassName" "algorithm" "keysize" "exemption_mechanism")'.
     *
     * @return information about this CryptoPermission.
     */
    public String toString() {
        StringBuilder buf = new StringBuilder(100);
        buf.append("(CryptoPermission " + alg + " " + maxKeySize);
        if (algParamSpec != null) {
            if (algParamSpec instanceof RC2ParameterSpec) {
                buf.append(" , effective " +
                    ((RC2ParameterSpec)algParamSpec).getEffectiveKeyBits());
            } else if (algParamSpec instanceof RC5ParameterSpec) {
                buf.append(" , rounds " +
                    ((RC5ParameterSpec)algParamSpec).getRounds());
            }
        }
        if (exemptionMechanism != null) { // OPTIONAL
            buf.append(" " + exemptionMechanism);
        }
        buf.append(")");
        return buf.toString();
    }

    private boolean impliesExemptionMechanism(String exemptionMechanism) {
        if (this.exemptionMechanism == null) {
            return true;
        }

        if (exemptionMechanism == null) {
            return false;
        }

        if (this.exemptionMechanism.equals(exemptionMechanism)) {
            return true;
        }

        return false;
    }

    private boolean impliesParameterSpec(boolean checkParam,
                                         AlgorithmParameterSpec algParamSpec) {
        if ((this.checkParam) && checkParam) {
            if (algParamSpec == null) {
                return true;
            } else if (this.algParamSpec == null) {
                return false;
            }

            if (this.algParamSpec.getClass() != algParamSpec.getClass()) {
                return false;
            }

            if (algParamSpec instanceof RC2ParameterSpec) {
                if (((RC2ParameterSpec)algParamSpec).getEffectiveKeyBits() <=
                    ((RC2ParameterSpec)
                     (this.algParamSpec)).getEffectiveKeyBits()) {
                    return true;
                }
            }

            if (algParamSpec instanceof RC5ParameterSpec) {
                if (((RC5ParameterSpec)algParamSpec).getRounds() <=
                    ((RC5ParameterSpec)this.algParamSpec).getRounds()) {
                    return true;
                }
            }

            if (algParamSpec instanceof PBEParameterSpec) {
                if (((PBEParameterSpec)algParamSpec).getIterationCount() <=
                    ((PBEParameterSpec)this.algParamSpec).getIterationCount()) {
                    return true;
                }
            }

            // For classes we don't know, the following
            // may be the best try.
            if (this.algParamSpec.equals(algParamSpec)) {
                return true;
            }
            return false;
        } else if (this.checkParam) {
            return false;
        } else {
            return true;
        }
    }

    private boolean equalObjects(Object obj1, Object obj2) {
        if (obj1 == null) {
            return (obj2 == null ? true : false);
        }

        return obj1.equals(obj2);
    }
}


A CryptoPermissionCollection stores a set of CryptoPermission
permissions.

Author:Sharon Liu
See Also:
/**
 * A CryptoPermissionCollection stores a set of CryptoPermission
 * permissions.
 *
 * @see java.security.Permission
 * @see java.security.Permissions
 * @see java.security.PermissionCollection
 *
 * @author Sharon Liu
 */
final class CryptoPermissionCollection extends PermissionCollection
    implements Serializable
{
    private static final long serialVersionUID = -511215555898802763L;

    private Vector<Permission> permissions;

    
Creates an empty CryptoPermissionCollection
object.

/**
     * Creates an empty CryptoPermissionCollection
     * object.
     */
    CryptoPermissionCollection() {
        permissions = new Vector<Permission>(3);
    }

    
Adds a permission to the CryptoPermissionCollection.

Params:
  • permission – the Permission object to add.
Throws:
  • SecurityException – - if this CryptoPermissionCollection
object has been marked readOnly.
/**
     * Adds a permission to the CryptoPermissionCollection.
     *
     * @param permission the Permission object to add.
     *
     * @exception SecurityException - if this CryptoPermissionCollection
     * object has been marked <i>readOnly</i>.
     */
    public void add(Permission permission) {
        if (isReadOnly())
            throw new SecurityException("attempt to add a Permission " +
                                        "to a readonly PermissionCollection");

        if (!(permission instanceof CryptoPermission))
            return;

        permissions.addElement(permission);
    }

    
Check and see if this CryptoPermission object implies
the given Permission object.

Params:
  • permission – the Permission object to compare
Returns:true if the given permission  is implied by this
CryptoPermissionCollection, false if not.
/**
     * Check and see if this CryptoPermission object implies
     * the given Permission object.
     *
     * @param permission the Permission object to compare
     *
     * @return true if the given permission  is implied by this
     * CryptoPermissionCollection, false if not.
     */
    public boolean implies(Permission permission) {
        if (!(permission instanceof CryptoPermission))
            return false;

        CryptoPermission cp = (CryptoPermission)permission;

        Enumeration<Permission> e = permissions.elements();

        while (e.hasMoreElements()) {
            CryptoPermission x = (CryptoPermission) e.nextElement();
            if (x.implies(cp)) {
                return true;
            }
        }
        return false;
    }

    
Returns an enumeration of all the CryptoPermission objects
in the container.

Returns:an enumeration of all the CryptoPermission objects.
/**
     * Returns an enumeration of all the CryptoPermission objects
     * in the container.
     *
     * @return an enumeration of all the CryptoPermission objects.
     */

    public Enumeration<Permission> elements() {
        return permissions.elements();
    }
}