package rsa;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: </p> * @author not attributable * @version 1.0 */public class PublicKey{        /** the public modulus */        protected BigInteger n_;        /** the public exponent */        protected BigInteger e_;        protected PublicKey()        {        }        /**         * create a public key from a modulus and exponent         * @param n0 The public modulus         * @param e0 The public exponent         */        public PublicKey( BigInteger n0, BigInteger e0 )        {                n_= new BigInteger( n0 );                e_= new BigInteger( e0 );        }        /**         * create a new public key from an existing key.         * @param from0 the key to copy.         */        public PublicKey( PublicKey from0 )        {                copy( from0 );        }        /**         * @return a new BigInteger equal to the public modulus         */        public final BigInteger        n()        {                return new BigInteger( n_ );        }        /**         * @return a new BigInteger equal to the public exponent         */        public final BigInteger        e()        {                return new BigInteger( e_ );        }        /**         * copies a key if it is an instance of cryptix.security.rsa.PublicKey.         * @param src this object to copy         */        public void        copy( Object src )        {                PublicKey from = (PublicKey)src;                n_ = new BigInteger( from.n_ );                e_ = new BigInteger( from.e_ );        }        /**         * tests if an object is equal to this one.         * @param obj object to test         * @return true if the object is equal, otherwise false.         */        public boolean equals( Object obj )        {                if ( obj instanceof PublicKey )                {                        PublicKey from = (PublicKey)obj;                        if ( n_.equals( from.n_ ) && e_.equals( from.e_ ) )                                return true;                }                return false;        }        /**         * gets the key id.         * @returns The lower 8 bytes of n, the public modulus.         */        public final byte[]        id()        {                byte nBuffer[] = n_.toByteArray();                byte ident[] = new byte[8];                System.arraycopy( nBuffer, nBuffer.length - 8, ident, 0, 8 );                return ident;        }        /**         * get the keys fingerprint.         * @return a MD5 hash of n and e.         */ /*       public final byte[]        fingerPrint()        {                byte eBuffer[] = e_.toByteArray();                byte nBuffer[] = n_.toByteArray();                MD5 md = new MD5();                md.add( nBuffer );                md.add( eBuffer );                return md.digest();        }*/        /**         * get the keys bit length.         * @return the length in bits of n, the public modulus.         */        public final int bitLength()        {                return n_.bitLength();        }        /**         * encrypts a number with this key.         * @param plain the number to encrypt.         * @return an encrypted number.         */        public BigInteger        encrypt( BigInteger plain )        {                return new BigInteger( plain ).modExp( e_, n_ );        }        /**         * @return this key in hex.         */        public String        toString()        {                return "n:" + n_ + "\ne:" + e_;        }}