* SubjectPublicKeyInfo ::= SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING
* }
*
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm OPTIONAL
* }
*
* * As indicated in RFC-2459: "The parameters field shall have ASN.1 type NULL * for this algorithm identifier.". *
* The subjectPublicKey field, which is a BIT STRING, contains the * DER-encoded form of the RSA public key defined as: * *
* RSAPublicKey ::= SEQUENCE {
* modulus INTEGER, -- n
* publicExponent INTEGER -- e
* }
*
*
* @param key the {@link PublicKey} instance to encode. MUST be an instance of
* {@link GnuRSAPublicKey}.
* @return the ASN.1 representation of the SubjectPublicKeyInfo in an
* X.509 certificate.
* @throw InvalidParameterException if key is not an instance
* of {@link GnuRSAPublicKey} or if an exception occurs during the
* marshalling process.
*/
public byte[] encodePublicKey(PublicKey key)
{
if (Configuration.DEBUG)
log.entering(this.getClass().getName(), "encodePublicKey()", key);
if (! (key instanceof GnuRSAPublicKey))
throw new InvalidParameterException("key");
DERValue derOID = new DERValue(DER.OBJECT_IDENTIFIER, RSA_ALG_OID);
GnuRSAPublicKey rsaKey = (GnuRSAPublicKey) key;
BigInteger n = rsaKey.getN();
BigInteger e = rsaKey.getE();
DERValue derN = new DERValue(DER.INTEGER, n);
DERValue derE = new DERValue(DER.INTEGER, e);
ArrayList algorithmID = new ArrayList(2);
algorithmID.add(derOID);
algorithmID.add(new DERValue(DER.NULL, null));
DERValue derAlgorithmID = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE,
algorithmID);
ArrayList publicKey = new ArrayList(2);
publicKey.add(derN);
publicKey.add(derE);
DERValue derPublicKey = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE,
publicKey);
byte[] spkBytes = derPublicKey.getEncoded();
DERValue derSPK = new DERValue(DER.BIT_STRING, new BitString(spkBytes));
ArrayList spki = new ArrayList(2);
spki.add(derAlgorithmID);
spki.add(derSPK);
DERValue derSPKI = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE, spki);
byte[] result;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try
{
DERWriter.write(baos, derSPKI);
result = baos.toByteArray();
}
catch (IOException x)
{
InvalidParameterException y = new InvalidParameterException(x.getMessage());
y.initCause(x);
throw y;
}
if (Configuration.DEBUG)
log.exiting(this.getClass().getName(), "encodePublicKey()", result);
return result;
}
/**
* @throws InvalidParameterException ALWAYS.
*/
public byte[] encodePrivateKey(PrivateKey key)
{
throw new InvalidParameterException("Wrong format for private keys");
}
/**
* @param input the byte array to unmarshall into a valid RSA
* {@link PublicKey} instance. MUST NOT be null.
* @return a new instance of a {@link GnuRSAPublicKey} decoded from the
* SubjectPublicKeyInfo material in an X.509 certificate.
* @throw InvalidParameterException if an exception occurs during the
* unmarshalling process.
*/
public PublicKey decodePublicKey(byte[] input)
{
if (Configuration.DEBUG)
log.entering(this.getClass().getName(), "decodePublicKey()", input);
if (input == null)
throw new InvalidParameterException("Input bytes MUST NOT be null");
BigInteger n, e;
DERReader der = new DERReader(input);
try
{
DERValue derSPKI = der.read();
DerUtil.checkIsConstructed(derSPKI, "Wrong SubjectPublicKeyInfo field");
DERValue derAlgorithmID = der.read();
DerUtil.checkIsConstructed(derAlgorithmID, "Wrong AlgorithmIdentifier field");
DERValue derOID = der.read();
if (! (derOID.getValue() instanceof OID))
throw new InvalidParameterException("Wrong Algorithm field");
OID algOID = (OID) derOID.getValue();
if (! algOID.equals(RSA_ALG_OID))
throw new InvalidParameterException("Unexpected OID: " + algOID);
// rfc-2459 states that this field is OPTIONAL but NULL if/when present
DERValue val = der.read();
if (val.getTag() == DER.NULL)
val = der.read();
if (! (val.getValue() instanceof BitString))
throw new InvalidParameterException("Wrong SubjectPublicKey field");
byte[] spkBytes = ((BitString) val.getValue()).toByteArray();
der = new DERReader(spkBytes);
val = der.read();
DerUtil.checkIsConstructed(derAlgorithmID, "Wrong subjectPublicKey field");
val = der.read();
DerUtil.checkIsBigInteger(val, "Wrong modulus field");
n = (BigInteger) val.getValue();
val = der.read();
DerUtil.checkIsBigInteger(val, "Wrong publicExponent field");
e = (BigInteger) val.getValue();
}
catch (IOException x)
{
InvalidParameterException y = new InvalidParameterException(x.getMessage());
y.initCause(x);
throw y;
}
PublicKey result = new GnuRSAPublicKey(Registry.X509_ENCODING_ID, n, e);
if (Configuration.DEBUG)
log.exiting(this.getClass().getName(), "decodePublicKey()", result);
return result;
}
/**
* @throws InvalidParameterException ALWAYS.
*/
public PrivateKey decodePrivateKey(byte[] input)
{
throw new InvalidParameterException("Wrong format for private keys");
}
}