/*
* Copyright (c) 1996, 2009, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.security.util;
import java.io.*;
import java.math.BigInteger;
import java.util.Date;
import sun.misc.IOUtils;
/**
* Represents a single DER-encoded value. DER encoding rules are a subset
* of the "Basic" Encoding Rules (BER), but they only support a single way
* ("Definite" encoding) to encode any given value.
*
* <P>All DER-encoded data are triples <em>{type, length, data}</em>. This
* class represents such tagged values as they have been read (or constructed),
* and provides structured access to the encoded data.
*
* <P>At this time, this class supports only a subset of the types of DER
* data encodings which are defined. That subset is sufficient for parsing
* most X.509 certificates, and working with selected additional formats
* (such as PKCS #10 certificate requests, and some kinds of PKCS #7 data).
*
* A note with respect to T61/Teletex strings: From RFC 1617, section 4.1.3
* and RFC 3280, section 4.1.2.4., we assume that this kind of string will
* contain ISO-8859-1 characters only.
*
*
* @author David Brownell
* @author Amit Kapoor
* @author Hemma Prafullchandra
*/
public class DerValue {
/** The tag class types */
public static final byte TAG_UNIVERSAL = (byte)0x000;
public static final byte TAG_APPLICATION = (byte)0x040;
public static final byte TAG_CONTEXT = (byte)0x080;
public static final byte TAG_PRIVATE = (byte)0x0c0;
/** The DER tag of the value; one of the tag_ constants. */
public byte tag;
protected DerInputBuffer buffer;
/**
* The DER-encoded data of the value.
*/
public final DerInputStream data;
private int length;
/*
* The type starts at the first byte of the encoding, and
* is one of these tag_* values. That may be all the type
* data that is needed.
*/
/*
* These tags are the "universal" tags ... they mean the same
* in all contexts. (Mask with 0x1f -- five bits.)
*/
/** Tag value indicating an ASN.1 "BOOLEAN" value. */
public final static byte tag_Boolean = 0x01;
/** Tag value indicating an ASN.1 "INTEGER" value. */
public final static byte tag_Integer = 0x02;
/** Tag value indicating an ASN.1 "BIT STRING" value. */
public final static byte tag_BitString = 0x03;
/** Tag value indicating an ASN.1 "OCTET STRING" value. */
public final static byte tag_OctetString = 0x04;
/** Tag value indicating an ASN.1 "NULL" value. */
public final static byte tag_Null = 0x05;
/** Tag value indicating an ASN.1 "OBJECT IDENTIFIER" value. */
public final static byte tag_ObjectId = 0x06;
/** Tag value including an ASN.1 "ENUMERATED" value */
public final static byte tag_Enumerated = 0x0A;
/** Tag value indicating an ASN.1 "UTF8String" value. */
public final static byte tag_UTF8String = 0x0C;
/** Tag value including a "printable" string */
public final static byte tag_PrintableString = 0x13;
/** Tag value including a "teletype" string */
public final static byte tag_T61String = 0x14;
/** Tag value including an ASCII string */
public final static byte tag_IA5String = 0x16;
/** Tag value indicating an ASN.1 "UTCTime" value. */
public final static byte tag_UtcTime = 0x17;
/** Tag value indicating an ASN.1 "GeneralizedTime" value. */
public final static byte tag_GeneralizedTime = 0x18;
/** Tag value indicating an ASN.1 "GenerallString" value. */
public final static byte tag_GeneralString = 0x1B;
/** Tag value indicating an ASN.1 "UniversalString" value. */
public final static byte tag_UniversalString = 0x1C;
/** Tag value indicating an ASN.1 "BMPString" value. */
public final static byte tag_BMPString = 0x1E;
// CONSTRUCTED seq/set
/**
* Tag value indicating an ASN.1
* "SEQUENCE" (zero to N elements, order is significant).
*/
public final static byte tag_Sequence = 0x30;
/**
* Tag value indicating an ASN.1
* "SEQUENCE OF" (one to N elements, order is significant).
*/
public final static byte tag_SequenceOf = 0x30;
/**
* Tag value indicating an ASN.1
* "SET" (zero to N members, order does not matter).
*/
public final static byte tag_Set = 0x31;
/**
* Tag value indicating an ASN.1
* "SET OF" (one to N members, order does not matter).
*/
public final static byte tag_SetOf = 0x31;
/*
* These values are the high order bits for the other kinds of tags.
*/
/**
* Returns true if the tag class is UNIVERSAL.
*/
public boolean isUniversal() { return ((tag & 0x0c0) == 0x000); }
/**
* Returns true if the tag class is APPLICATION.
*/
public boolean isApplication() { return ((tag & 0x0c0) == 0x040); }
/**
* Returns true iff the CONTEXT SPECIFIC bit is set in the type tag.
* This is associated with the ASN.1 "DEFINED BY" syntax.
*/
public boolean isContextSpecific() { return ((tag & 0x0c0) == 0x080); }
/**
* Returns true iff the CONTEXT SPECIFIC TAG matches the passed tag.
*/
public boolean isContextSpecific(byte cntxtTag) {
if (!isContextSpecific()) {
return false;
}
return ((tag & 0x01f) == cntxtTag);
}
boolean isPrivate() { return ((tag & 0x0c0) == 0x0c0); }
/** Returns true iff the CONSTRUCTED bit is set in the type tag. */
public boolean isConstructed() { return ((tag & 0x020) == 0x020); }
/**
* Returns true iff the CONSTRUCTED TAG matches the passed tag.
*/
public boolean isConstructed(byte constructedTag) {
if (!isConstructed()) {
return false;
}
return ((tag & 0x01f) == constructedTag);
}
/**
* Creates a PrintableString or UTF8string DER value from a string
*/
public DerValue(String value) throws IOException {
boolean isPrintableString = true;
for (int i = 0; i < value.length(); i++) {
if (!isPrintableStringChar(value.charAt(i))) {
isPrintableString = false;
break;
}
}
data = init(isPrintableString ? tag_PrintableString : tag_UTF8String, value);
}
/**
* Creates a string type DER value from a String object
* @param stringTag the tag for the DER value to create
* @param value the String object to use for the DER value
*/
public DerValue(byte stringTag, String value) throws IOException {
data = init(stringTag, value);
}
/**
* Creates a DerValue from a tag and some DER-encoded data.
*
* @param tag the DER type tag
* @param data the DER-encoded data
*/
public DerValue(byte tag, byte[] data) {
this.tag = tag;
buffer = new DerInputBuffer(data.clone());
length = data.length;
this.data = new DerInputStream(buffer);
this.data.mark(Integer.MAX_VALUE);
}
/*
* package private
*/
DerValue(DerInputBuffer in) throws IOException {
// XXX must also parse BER-encoded constructed
// values such as sequences, sets...
tag = (byte)in.read();
byte lenByte = (byte)in.read();
length = DerInputStream.getLength((lenByte & 0xff), in);
if (length == -1) { // indefinite length encoding found
DerInputBuffer inbuf = in.dup();
int readLen = inbuf.available();
int offset = 2; // for tag and length bytes
byte[] indefData = new byte[readLen + offset];
indefData[0] = tag;
indefData[1] = lenByte;
DataInputStream dis = new DataInputStream(inbuf);
dis.readFully(indefData, offset, readLen);
dis.close();
DerIndefLenConverter derIn = new DerIndefLenConverter();
inbuf = new DerInputBuffer(derIn.convert(indefData));
if (tag != inbuf.read())
throw new IOException
("Indefinite length encoding not supported");
length = DerInputStream.getLength(inbuf);
buffer = inbuf.dup();
buffer.truncate(length);
data = new DerInputStream(buffer);
// indefinite form is encoded by sending a length field with a
// length of 0. - i.e. [1000|0000].
// the object is ended by sending two zero bytes.
in.skip(length + offset);
} else {
buffer = in.dup();
buffer.truncate(length);
data = new DerInputStream(buffer);
in.skip(length);
}
}
/**
* Get an ASN.1/DER encoded datum from a buffer. The
* entire buffer must hold exactly one datum, including
* its tag and length.
*
* @param buf buffer holding a single DER-encoded datum.
*/
public DerValue(byte[] buf) throws IOException {
data = init(true, new ByteArrayInputStream(buf));
}
/**
* Get an ASN.1/DER encoded datum from part of a buffer.
* That part of the buffer must hold exactly one datum, including
* its tag and length.
*
* @param buf the buffer
* @param offset start point of the single DER-encoded dataum
* @param length how many bytes are in the encoded datum
*/
public DerValue(byte[] buf, int offset, int len) throws IOException {
data = init(true, new ByteArrayInputStream(buf, offset, len));
}
/**
* Get an ASN1/DER encoded datum from an input stream. The
* stream may have additional data following the encoded datum.
* In case of indefinite length encoded datum, the input stream
* must hold only one datum.
*
* @param in the input stream holding a single DER datum,
* which may be followed by additional data
*/
public DerValue(InputStream in) throws IOException {
data = init(false, in);
}
private DerInputStream init(byte stringTag, String value) throws IOException {
String enc = null;
tag = stringTag;
switch (stringTag) {
case tag_PrintableString:
case tag_IA5String:
case tag_GeneralString:
enc = "ASCII";
break;
case tag_T61String:
enc = "ISO-8859-1";
break;
case tag_BMPString:
enc = "UnicodeBigUnmarked";
break;
case tag_UTF8String:
enc = "UTF8";
break;
// TBD: Need encoder for UniversalString before it can
// be handled.
default:
throw new IllegalArgumentException("Unsupported DER string type");
}
byte[] buf = value.getBytes(enc);
length = buf.length;
buffer = new DerInputBuffer(buf);
DerInputStream result = new DerInputStream(buffer);
result.mark(Integer.MAX_VALUE);
return result;
}
/*
* helper routine
*/
private DerInputStream init(boolean fullyBuffered, InputStream in)
throws IOException {
tag = (byte)in.read();
byte lenByte = (byte)in.read();
length = DerInputStream.getLength((lenByte & 0xff), in);
if (length == -1) { // indefinite length encoding found
int readLen = in.available();
int offset = 2; // for tag and length bytes
byte[] indefData = new byte[readLen + offset];
indefData[0] = tag;
indefData[1] = lenByte;
DataInputStream dis = new DataInputStream(in);
dis.readFully(indefData, offset, readLen);
dis.close();
DerIndefLenConverter derIn = new DerIndefLenConverter();
in = new ByteArrayInputStream(derIn.convert(indefData));
if (tag != in.read())
throw new IOException
("Indefinite length encoding not supported");
length = DerInputStream.getLength(in);
}
if (length == 0)
return null;
if (fullyBuffered && in.available() != length)
throw new IOException("extra data given to DerValue constructor");
byte[] bytes = IOUtils.readFully(in, length, true);
buffer = new DerInputBuffer(bytes);
return new DerInputStream(buffer);
}
/**
* Encode an ASN1/DER encoded datum onto a DER output stream.
*/
public void encode(DerOutputStream out)
throws IOException {
out.write(tag);
out.putLength(length);
// XXX yeech, excess copies ... DerInputBuffer.write(OutStream)
if (length > 0) {
byte[] value = new byte[length];
// always synchronized on data
synchronized (data) {
buffer.reset();
if (buffer.read(value) != length) {
throw new IOException("short DER value read (encode)");
}
out.write(value);
}
}
}
public final DerInputStream getData() {
return data;
}
public final byte getTag() {
return tag;
}
/**
* Returns an ASN.1 BOOLEAN
*
* @return the boolean held in this DER value
*/
public boolean getBoolean() throws IOException {
if (tag != tag_Boolean) {
throw new IOException("DerValue.getBoolean, not a BOOLEAN " + tag);
}
if (length != 1) {
throw new IOException("DerValue.getBoolean, invalid length "
+ length);
}
if (buffer.read() != 0) {
return true;
}
return false;
}
/**
* Returns an ASN.1 OBJECT IDENTIFIER.
*
* @return the OID held in this DER value
*/
public ObjectIdentifier getOID() throws IOException {
if (tag != tag_ObjectId)
throw new IOException("DerValue.getOID, not an OID " + tag);
return new ObjectIdentifier(buffer);
}
private byte[] append(byte[] a, byte[] b) {
if (a == null)
return b;
byte[] ret = new byte[a.length + b.length];
System.arraycopy(a, 0, ret, 0, a.length);
System.arraycopy(b, 0, ret, a.length, b.length);
return ret;
}
/**
* Returns an ASN.1 OCTET STRING
*
* @return the octet string held in this DER value
*/
public byte[] getOctetString() throws IOException {
byte[] bytes;
if (tag != tag_OctetString && !isConstructed(tag_OctetString)) {
throw new IOException(
"DerValue.getOctetString, not an Octet String: " + tag);
}
bytes = new byte[length];
if (buffer.read(bytes) != length)
throw new IOException("short read on DerValue buffer");
if (isConstructed()) {
DerInputStream in = new DerInputStream(bytes);
bytes = null;
while (in.available() != 0) {
bytes = append(bytes, in.getOctetString());
}
}
return bytes;
}
/**
* Returns an ASN.1 INTEGER value as an integer.
*
* @return the integer held in this DER value.
*/
public int getInteger() throws IOException {
if (tag != tag_Integer) {
throw new IOException("DerValue.getInteger, not an int " + tag);
}
return buffer.getInteger(data.available());
}
/**
* Returns an ASN.1 INTEGER value as a BigInteger.
*
* @return the integer held in this DER value as a BigInteger.
*/
public BigInteger getBigInteger() throws IOException {
if (tag != tag_Integer)
throw new IOException("DerValue.getBigInteger, not an int " + tag);
return buffer.getBigInteger(data.available(), false);
}
/**
* Returns an ASN.1 INTEGER value as a positive BigInteger.
* This is just to deal with implementations that incorrectly encode
* some values as negative.
*
* @return the integer held in this DER value as a BigInteger.
*/
public BigInteger getPositiveBigInteger() throws IOException {
if (tag != tag_Integer)
throw new IOException("DerValue.getBigInteger, not an int " + tag);
return buffer.getBigInteger(data.available(), true);
}
/**
* Returns an ASN.1 ENUMERATED value.
*
* @return the integer held in this DER value.
*/
public int getEnumerated() throws IOException {
if (tag != tag_Enumerated) {
throw new IOException("DerValue.getEnumerated, incorrect tag: "
+ tag);
}
return buffer.getInteger(data.available());
}
/**
* Returns an ASN.1 BIT STRING value. The bit string must be byte-aligned.
*
* @return the bit string held in this value
*/
public byte[] getBitString() throws IOException {
if (tag != tag_BitString)
throw new IOException(
"DerValue.getBitString, not a bit string " + tag);
return buffer.getBitString();
}
/**
* Returns an ASN.1 BIT STRING value that need not be byte-aligned.
*
* @return a BitArray representing the bit string held in this value
*/
public BitArray getUnalignedBitString() throws IOException {
if (tag != tag_BitString)
throw new IOException(
"DerValue.getBitString, not a bit string " + tag);
return buffer.getUnalignedBitString();
}
/**
* Returns the name component as a Java string, regardless of its
* encoding restrictions (ASCII, T61, Printable, IA5, BMP, UTF8).
*/
// TBD: Need encoder for UniversalString before it can be handled.
public String getAsString() throws IOException {
if (tag == tag_UTF8String)
return getUTF8String();
else if (tag == tag_PrintableString)
return getPrintableString();
else if (tag == tag_T61String)
return getT61String();
else if (tag == tag_IA5String)
return getIA5String();
/*
else if (tag == tag_UniversalString)
return getUniversalString();
*/
else if (tag == tag_BMPString)
return getBMPString();
else if (tag == tag_GeneralString)
return getGeneralString();
else
return null;
}
/**
* Returns an ASN.1 BIT STRING value, with the tag assumed implicit
* based on the parameter. The bit string must be byte-aligned.
*
* @params tagImplicit if true, the tag is assumed implicit.
* @return the bit string held in this value
*/
public byte[] getBitString(boolean tagImplicit) throws IOException {
if (!tagImplicit) {
if (tag != tag_BitString)
throw new IOException("DerValue.getBitString, not a bit string "
+ tag);
}
return buffer.getBitString();
}
/**
* Returns an ASN.1 BIT STRING value, with the tag assumed implicit
* based on the parameter. The bit string need not be byte-aligned.
*
* @params tagImplicit if true, the tag is assumed implicit.
* @return the bit string held in this value
*/
public BitArray getUnalignedBitString(boolean tagImplicit)
throws IOException {
if (!tagImplicit) {
if (tag != tag_BitString)
throw new IOException("DerValue.getBitString, not a bit string "
+ tag);
}
return buffer.getUnalignedBitString();
}
/**
* Helper routine to return all the bytes contained in the
* DerInputStream associated with this object.
*/
public byte[] getDataBytes() throws IOException {
byte[] retVal = new byte[length];
synchronized (data) {
data.reset();
data.getBytes(retVal);
}
return retVal;
}
/**
* Returns an ASN.1 STRING value
*
* @return the printable string held in this value
*/
public String getPrintableString()
throws IOException {
if (tag != tag_PrintableString)
throw new IOException(
"DerValue.getPrintableString, not a string " + tag);
return new String(getDataBytes(), "ASCII");
}
/**
* Returns an ASN.1 T61 (Teletype) STRING value
*
* @return the teletype string held in this value
*/
public String getT61String() throws IOException {
if (tag != tag_T61String)
throw new IOException(
"DerValue.getT61String, not T61 " + tag);
return new String(getDataBytes(), "ISO-8859-1");
}
/**
* Returns an ASN.1 IA5 (ASCII) STRING value
*
* @return the ASCII string held in this value
*/
public String getIA5String() throws IOException {
if (tag != tag_IA5String)
throw new IOException(
"DerValue.getIA5String, not IA5 " + tag);
return new String(getDataBytes(), "ASCII");
}
/**
* Returns the ASN.1 BMP (Unicode) STRING value as a Java string.
*
* @return a string corresponding to the encoded BMPString held in
* this value
*/
public String getBMPString() throws IOException {
if (tag != tag_BMPString)
throw new IOException(
"DerValue.getBMPString, not BMP " + tag);
// BMPString is the same as Unicode in big endian, unmarked
// format.
return new String(getDataBytes(), "UnicodeBigUnmarked");
}
/**
* Returns the ASN.1 UTF-8 STRING value as a Java String.
*
* @return a string corresponding to the encoded UTF8String held in
* this value
*/
public String getUTF8String() throws IOException {
if (tag != tag_UTF8String)
throw new IOException(
"DerValue.getUTF8String, not UTF-8 " + tag);
return new String(getDataBytes(), "UTF8");
}
/**
* Returns the ASN.1 GENERAL STRING value as a Java String.
*
* @return a string corresponding to the encoded GeneralString held in
* this value
*/
public String getGeneralString() throws IOException {
if (tag != tag_GeneralString)
throw new IOException(
"DerValue.getGeneralString, not GeneralString " + tag);
return new String(getDataBytes(), "ASCII");
}
/**
* Returns a Date if the DerValue is UtcTime.
*
* @return the Date held in this DER value
*/
public Date getUTCTime() throws IOException {
if (tag != tag_UtcTime) {
throw new IOException("DerValue.getUTCTime, not a UtcTime: " + tag);
}
return buffer.getUTCTime(data.available());
}
/**
* Returns a Date if the DerValue is GeneralizedTime.
*
* @return the Date held in this DER value
*/
public Date getGeneralizedTime() throws IOException {
if (tag != tag_GeneralizedTime) {
throw new IOException(
"DerValue.getGeneralizedTime, not a GeneralizedTime: " + tag);
}
return buffer.getGeneralizedTime(data.available());
}
/**
* Returns true iff the other object is a DER value which
* is bitwise equal to this one.
*
* @param other the object being compared with this one
*/
public boolean equals(Object other) {
if (other instanceof DerValue)
return equals((DerValue)other);
else
return false;
}
/**
* Bitwise equality comparison. DER encoded values have a single
* encoding, so that bitwise equality of the encoded values is an
* efficient way to establish equivalence of the unencoded values.
*
* @param other the object being compared with this one
*/
public boolean equals(DerValue other) {
if (this == other) {
return true;
}
if (tag != other.tag) {
return false;
}
if (data == other.data) {
return true;
}
// make sure the order of lock is always consistent to avoid a deadlock
return (System.identityHashCode(this.data)
> System.identityHashCode(other.data)) ?
doEquals(this, other):
doEquals(other, this);
}
/**
* Helper for public method equals()
*/
private static boolean doEquals(DerValue d1, DerValue d2) {
synchronized (d1.data) {
synchronized (d2.data) {
d1.data.reset();
d2.data.reset();
return d1.buffer.equals(d2.buffer);
}
}
}
/**
* Returns a printable representation of the value.
*
* @return printable representation of the value
*/
public String toString() {
try {
String str = getAsString();
if (str != null)
return "\"" + str + "\"";
if (tag == tag_Null)
return "[DerValue, null]";
if (tag == tag_ObjectId)
return "OID." + getOID();
// integers
else
return "[DerValue, tag = " + tag
+ ", length = " + length + "]";
} catch (IOException e) {
throw new IllegalArgumentException("misformatted DER value");
}
}
/**
* Returns a DER-encoded value, such that if it's passed to the
* DerValue constructor, a value equivalent to "this" is returned.
*
* @return DER-encoded value, including tag and length.
*/
public byte[] toByteArray() throws IOException {
DerOutputStream out = new DerOutputStream();
encode(out);
data.reset();
return out.toByteArray();
}
/**
* For "set" and "sequence" types, this function may be used
* to return a DER stream of the members of the set or sequence.
* This operation is not supported for primitive types such as
* integers or bit strings.
*/
public DerInputStream toDerInputStream() throws IOException {
if (tag == tag_Sequence || tag == tag_Set)
return new DerInputStream(buffer);
throw new IOException("toDerInputStream rejects tag type " + tag);
}
/**
* Get the length of the encoded value.
*/
public int length() {
return length;
}
/**
* Determine if a character is one of the permissible characters for
* PrintableString:
* A-Z, a-z, 0-9, space, apostrophe (39), left and right parentheses,
* plus sign, comma, hyphen, period, slash, colon, equals sign,
* and question mark.
*
* Characters that are *not* allowed in PrintableString include
* exclamation point, quotation mark, number sign, dollar sign,
* percent sign, ampersand, asterisk, semicolon, less than sign,
* greater than sign, at sign, left and right square brackets,
* backslash, circumflex (94), underscore, back quote (96),
* left and right curly brackets, vertical line, tilde,
* and the control codes (0-31 and 127).
*
* This list is based on X.680 (the ASN.1 spec).
*/
public static boolean isPrintableStringChar(char ch) {
if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') ||
(ch >= '0' && ch <= '9')) {
return true;
} else {
switch (ch) {
case ' ': /* space */
case '\'': /* apostrophe */
case '(': /* left paren */
case ')': /* right paren */
case '+': /* plus */
case ',': /* comma */
case '-': /* hyphen */
case '.': /* period */
case '/': /* slash */
case ':': /* colon */
case '=': /* equals */
case '?': /* question mark */
return true;
default:
return false;
}
}
}
/**
* Create the tag of the attribute.
*
* @params class the tag class type, one of UNIVERSAL, CONTEXT,
* APPLICATION or PRIVATE
* @params form if true, the value is constructed, otherwise it
* is primitive.
* @params val the tag value
*/
public static byte createTag(byte tagClass, boolean form, byte val) {
byte tag = (byte)(tagClass | val);
if (form) {
tag |= (byte)0x20;
}
return (tag);
}
/**
* Set the tag of the attribute. Commonly used to reset the
* tag value used for IMPLICIT encodings.
*
* @params tag the tag value
*/
public void resetTag(byte tag) {
this.tag = tag;
}
/**
* Returns a hashcode for this DerValue.
*
* @return a hashcode for this DerValue.
*/
public int hashCode() {
return toString().hashCode();
}
}