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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.security.x509;

import java.io.*;
import java.util.Arrays;
import java.util.Properties;
import java.security.Key;
import java.security.PublicKey;
import java.security.KeyFactory;
import java.security.Security;
import java.security.Provider;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;

import sun.security.util.HexDumpEncoder;
import sun.security.util.*;


Holds an X.509 key, for example a public key found in an X.509
certificate.  Includes a description of the algorithm to be used
with the key; these keys normally are used as
"SubjectPublicKeyInfo".

While this class can represent any kind of X.509 key, it may be
desirable to provide subclasses which understand how to parse keying
data.   For example, RSA public keys have two members, one for the
public modulus and one for the prime exponent.  If such a class is
provided, it is used when parsing X.509 keys.  If one is not provided,
the key still parses correctly.

Author:David Brownell
/**
 * Holds an X.509 key, for example a public key found in an X.509
 * certificate.  Includes a description of the algorithm to be used
 * with the key; these keys normally are used as
 * "SubjectPublicKeyInfo".
 *
 * <P>While this class can represent any kind of X.509 key, it may be
 * desirable to provide subclasses which understand how to parse keying
 * data.   For example, RSA public keys have two members, one for the
 * public modulus and one for the prime exponent.  If such a class is
 * provided, it is used when parsing X.509 keys.  If one is not provided,
 * the key still parses correctly.
 *
 * @author David Brownell
 */
public class X509Key implements PublicKey {

    
use serialVersionUID from JDK 1.1. for interoperability 
/** use serialVersionUID from JDK 1.1. for interoperability */
    private static final long serialVersionUID = -5359250853002055002L;

    /* The algorithm information (name, parameters, etc). */
    protected AlgorithmId algid;

    
The key bytes, without the algorithm information.

See Also:
Deprecated:Use the BitArray form which does not require keys to
be byte aligned.
/**
     * The key bytes, without the algorithm information.
     * @deprecated Use the BitArray form which does not require keys to
     * be byte aligned.
     * @see sun.security.x509.X509Key#setKey(BitArray)
     * @see sun.security.x509.X509Key#getKey()
     */
    @Deprecated
    protected byte[] key = null;

    /*
     * The number of bits unused in the last byte of the key.
     * Added to keep the byte[] key form consistent with the BitArray
     * form. Can de deleted when byte[] key is deleted.
     */
    @Deprecated
    private int unusedBits = 0;

    /* BitArray form of key */
    private BitArray bitStringKey = null;

    /* The encoding for the key. */
    protected byte[] encodedKey;

    
Default constructor.  The key constructed must have its key
and algorithm initialized before it may be used, for example
by using decode.

/**
     * Default constructor.  The key constructed must have its key
     * and algorithm initialized before it may be used, for example
     * by using <code>decode</code>.
     */
    public X509Key() { }

    /*
     * Build and initialize as a "default" key.  All X.509 key
     * data is stored and transmitted losslessly, but no knowledge
     * about this particular algorithm is available.
     */
    private X509Key(AlgorithmId algid, BitArray key)
    throws InvalidKeyException {
        this.algid = algid;
        setKey(key);
        encode();
    }

    
Sets the key in the BitArray form.

/**
     * Sets the key in the BitArray form.
     */
    protected void setKey(BitArray key) {
        this.bitStringKey = (BitArray)key.clone();

        /*
         * Do this to keep the byte array form consistent with
         * this. Can delete when byte[] key is deleted.
         */
        this.key = key.toByteArray();
        int remaining = key.length() % 8;
        this.unusedBits =
            ((remaining == 0) ? 0 : 8 - remaining);
    }

    
Gets the key. The key may or may not be byte aligned.

Returns:a BitArray containing the key.
/**
     * Gets the key. The key may or may not be byte aligned.
     * @return a BitArray containing the key.
     */
    protected BitArray getKey() {
        /*
         * Do this for consistency in case a subclass
         * modifies byte[] key directly. Remove when
         * byte[] key is deleted.
         * Note: the consistency checks fail when the subclass
         * modifies a non byte-aligned key (into a byte-aligned key)
         * using the deprecated byte[] key field.
         */
        this.bitStringKey = new BitArray(
                          this.key.length * 8 - this.unusedBits,
                          this.key);

        return (BitArray)bitStringKey.clone();
    }

    
Construct X.509 subject public key from a DER value.  If
the runtime environment is configured with a specific class for
this kind of key, a subclass is returned.  Otherwise, a generic
X509Key object is returned.

This mechanism gurantees that keys (and algorithms) may be
freely manipulated and transferred, without risk of losing
information.  Also, when a key (or algorithm) needs some special
handling, that specific need can be accomodated.

Params:
  • in – the DER-encoded SubjectPublicKeyInfo value
Throws:
/**
     * Construct X.509 subject public key from a DER value.  If
     * the runtime environment is configured with a specific class for
     * this kind of key, a subclass is returned.  Otherwise, a generic
     * X509Key object is returned.
     *
     * <P>This mechanism gurantees that keys (and algorithms) may be
     * freely manipulated and transferred, without risk of losing
     * information.  Also, when a key (or algorithm) needs some special
     * handling, that specific need can be accomodated.
     *
     * @param in the DER-encoded SubjectPublicKeyInfo value
     * @exception IOException on data format errors
     */
    public static PublicKey parse(DerValue in) throws IOException
    {
        AlgorithmId     algorithm;
        PublicKey       subjectKey;

        if (in.tag != DerValue.tag_Sequence)
            throw new IOException("corrupt subject key");

        algorithm = AlgorithmId.parse(in.data.getDerValue());
        try {
            subjectKey = buildX509Key(algorithm,
                                      in.data.getUnalignedBitString());

        } catch (InvalidKeyException e) {
            throw new IOException("subject key, " + e.getMessage(), e);
        }

        if (in.data.available() != 0)
            throw new IOException("excess subject key");
        return subjectKey;
    }

    
Parse the key bits.  This may be redefined by subclasses to take
advantage of structure within the key.  For example, RSA public
keys encapsulate two unsigned integers (modulus and exponent) as
DER values within the key bits; Diffie-Hellman and
DSS/DSA keys encapsulate a single unsigned integer.

This function is called when creating X.509 SubjectPublicKeyInfo
values using the X509Key member functions, such as parse
and decode.

Throws:
/**
     * Parse the key bits.  This may be redefined by subclasses to take
     * advantage of structure within the key.  For example, RSA public
     * keys encapsulate two unsigned integers (modulus and exponent) as
     * DER values within the <code>key</code> bits; Diffie-Hellman and
     * DSS/DSA keys encapsulate a single unsigned integer.
     *
     * <P>This function is called when creating X.509 SubjectPublicKeyInfo
     * values using the X509Key member functions, such as <code>parse</code>
     * and <code>decode</code>.
     *
     * @exception IOException on parsing errors.
     * @exception InvalidKeyException on invalid key encodings.
     */
    protected void parseKeyBits() throws IOException, InvalidKeyException {
        encode();
    }

    /*
     * Factory interface, building the kind of key associated with this
     * specific algorithm ID or else returning this generic base class.
     * See the description above.
     */
    static PublicKey buildX509Key(AlgorithmId algid, BitArray key)
      throws IOException, InvalidKeyException
    {
        /*
         * Use the algid and key parameters to produce the ASN.1 encoding
         * of the key, which will then be used as the input to the
         * key factory.
         */
        DerOutputStream x509EncodedKeyStream = new DerOutputStream();
        encode(x509EncodedKeyStream, algid, key);
        X509EncodedKeySpec x509KeySpec
            = new X509EncodedKeySpec(x509EncodedKeyStream.toByteArray());

        try {
            // Instantiate the key factory of the appropriate algorithm
            KeyFactory keyFac = KeyFactory.getInstance(algid.getName());

            // Generate the public key
            return keyFac.generatePublic(x509KeySpec);
        } catch (NoSuchAlgorithmException e) {
            // Return generic X509Key with opaque key data (see below)
        } catch (InvalidKeySpecException e) {
            throw new InvalidKeyException(e.getMessage(), e);
        }

        /*
         * Try again using JDK1.1-style for backwards compatibility.
         */
        String classname = "";
        try {
            Properties props;
            String keytype;
            Provider sunProvider;

            sunProvider = Security.getProvider("SUN");
            if (sunProvider == null)
                throw new InstantiationException();
            classname = sunProvider.getProperty("PublicKey.X.509." +
              algid.getName());
            if (classname == null) {
                throw new InstantiationException();
            }

            Class<?> keyClass = null;
            try {
                keyClass = Class.forName(classname);
            } catch (ClassNotFoundException e) {
                ClassLoader cl = ClassLoader.getSystemClassLoader();
                if (cl != null) {
                    keyClass = cl.loadClass(classname);
                }
            }

            @SuppressWarnings("deprecation")
            Object      inst = (keyClass != null) ? keyClass.newInstance() : null;
            X509Key     result;

            if (inst instanceof X509Key) {
                result = (X509Key) inst;
                result.algid = algid;
                result.setKey(key);
                result.parseKeyBits();
                return result;
            }
        } catch (ClassNotFoundException e) {
        } catch (InstantiationException e) {
        } catch (IllegalAccessException e) {
            // this should not happen.
            throw new IOException (classname + " [internal error]");
        }

        X509Key result = new X509Key(algid, key);
        return result;
    }

    
Returns the algorithm to be used with this key.

/**
     * Returns the algorithm to be used with this key.
     */
    public String getAlgorithm() {
        return algid.getName();
    }

    
Returns the algorithm ID to be used with this key.

/**
     * Returns the algorithm ID to be used with this key.
     */
    public AlgorithmId  getAlgorithmId() { return algid; }

    
Encode SubjectPublicKeyInfo sequence on the DER output stream.

Throws:
  • IOException – on encoding errors.
/**
     * Encode SubjectPublicKeyInfo sequence on the DER output stream.
     *
     * @exception IOException on encoding errors.
     */
    public final void encode(DerOutputStream out) throws IOException
    {
        encode(out, this.algid, getKey());
    }

    
Returns the DER-encoded form of the key as a byte array.

/**
     * Returns the DER-encoded form of the key as a byte array.
     */
    public byte[] getEncoded() {
        try {
            return getEncodedInternal().clone();
        } catch (InvalidKeyException e) {
            // XXX
        }
        return null;
    }

    public byte[] getEncodedInternal() throws InvalidKeyException {
        byte[] encoded = encodedKey;
        if (encoded == null) {
            try {
                DerOutputStream out = new DerOutputStream();
                encode(out);
                encoded = out.toByteArray();
            } catch (IOException e) {
                throw new InvalidKeyException("IOException : " +
                                               e.getMessage());
            }
            encodedKey = encoded;
        }
        return encoded;
    }

    
Returns the format for this key: "X.509"

/**
     * Returns the format for this key: "X.509"
     */
    public String getFormat() {
        return "X.509";
    }

    
Returns the DER-encoded form of the key as a byte array.

Throws:
  • InvalidKeyException – on encoding errors.
/**
     * Returns the DER-encoded form of the key as a byte array.
     *
     * @exception InvalidKeyException on encoding errors.
     */
    public byte[] encode() throws InvalidKeyException {
        return getEncodedInternal().clone();
    }

    /*
     * Returns a printable representation of the key
     */
    public String toString()
    {
        HexDumpEncoder  encoder = new HexDumpEncoder();

        return "algorithm = " + algid.toString()
            + ", unparsed keybits = \n" + encoder.encodeBuffer(key);
    }

    
Initialize an X509Key object from an input stream.  The data on that
input stream must be encoded using DER, obeying the X.509
SubjectPublicKeyInfo format.  That is, the data is a
sequence consisting of an algorithm ID and a bit string which holds
the key.  (That bit string is often used to encapsulate another DER
encoded sequence.)

Subclasses should not normally redefine this method; they should
instead provide a parseKeyBits method to parse any
fields inside the key member.

The exception to this rule is that since private keys need not
be encoded using the X.509 SubjectPublicKeyInfo format,
private keys may override this method, encode, and
of course getFormat.

Params:
  • in – an input stream with a DER-encoded X.509
         SubjectPublicKeyInfo value
Throws:
/**
     * Initialize an X509Key object from an input stream.  The data on that
     * input stream must be encoded using DER, obeying the X.509
     * <code>SubjectPublicKeyInfo</code> format.  That is, the data is a
     * sequence consisting of an algorithm ID and a bit string which holds
     * the key.  (That bit string is often used to encapsulate another DER
     * encoded sequence.)
     *
     * <P>Subclasses should not normally redefine this method; they should
     * instead provide a <code>parseKeyBits</code> method to parse any
     * fields inside the <code>key</code> member.
     *
     * <P>The exception to this rule is that since private keys need not
     * be encoded using the X.509 <code>SubjectPublicKeyInfo</code> format,
     * private keys may override this method, <code>encode</code>, and
     * of course <code>getFormat</code>.
     *
     * @param in an input stream with a DER-encoded X.509
     *          SubjectPublicKeyInfo value
     * @exception InvalidKeyException on parsing errors.
     */
    public void decode(InputStream in)
    throws InvalidKeyException
    {
        DerValue        val;

        try {
            val = new DerValue(in);
            if (val.tag != DerValue.tag_Sequence)
                throw new InvalidKeyException("invalid key format");

            algid = AlgorithmId.parse(val.data.getDerValue());
            setKey(val.data.getUnalignedBitString());
            parseKeyBits();
            if (val.data.available() != 0)
                throw new InvalidKeyException ("excess key data");

        } catch (IOException e) {
            throw new InvalidKeyException("IOException: " +
                                          e.getMessage());
        }
    }

    public void decode(byte[] encodedKey) throws InvalidKeyException {
        decode(new ByteArrayInputStream(encodedKey));
    }

    
Serialization write ... X.509 keys serialize as
themselves, and they're parsed when they get read back.

/**
     * Serialization write ... X.509 keys serialize as
     * themselves, and they're parsed when they get read back.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.write(getEncoded());
    }

    
Serialization read ... X.509 keys serialize as
themselves, and they're parsed when they get read back.

/**
     * Serialization read ... X.509 keys serialize as
     * themselves, and they're parsed when they get read back.
     */
    private void readObject(ObjectInputStream stream) throws IOException {
        try {
            decode(stream);
        } catch (InvalidKeyException e) {
            e.printStackTrace();
            throw new IOException("deserialized key is invalid: " +
                                  e.getMessage());
        }
    }

    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof Key == false) {
            return false;
        }
        try {
            byte[] thisEncoded = this.getEncodedInternal();
            byte[] otherEncoded;
            if (obj instanceof X509Key) {
                otherEncoded = ((X509Key)obj).getEncodedInternal();
            } else {
                otherEncoded = ((Key)obj).getEncoded();
            }
            return Arrays.equals(thisEncoded, otherEncoded);
        } catch (InvalidKeyException e) {
            return false;
        }
    }

    
Calculates a hash code value for the object. Objects
which are equal will also have the same hashcode.

/**
     * Calculates a hash code value for the object. Objects
     * which are equal will also have the same hashcode.
     */
    public int hashCode() {
        try {
            byte[] b1 = getEncodedInternal();
            int r = b1.length;
            for (int i = 0; i < b1.length; i++) {
                r += (b1[i] & 0xff) * 37;
            }
            return r;
        } catch (InvalidKeyException e) {
            // should not happen
            return 0;
        }
    }

    /*
     * Produce SubjectPublicKey encoding from algorithm id and key material.
     */
    static void encode(DerOutputStream out, AlgorithmId algid, BitArray key)
        throws IOException {
            DerOutputStream tmp = new DerOutputStream();
            algid.encode(tmp);
            tmp.putUnalignedBitString(key);
            out.write(DerValue.tag_Sequence, tmp);
    }
}