static byte[] buildDH(DHPublicKey key) {
DataByteOutputStream out = new DataByteOutputStream();
BigInteger p = key.getParams().getP();
BigInteger g = key.getParams().getG();
BigInteger y = key.getY();
int pLength, gLength, yLength;
if (g.equals(TWO) && (p.equals(DHPRIME768) || p.equals(DHPRIME1024))) {
pLength = 1;
gLength = 0;
} else {
pLength = BigIntegerLength(p);
gLength = BigIntegerLength(g);
}
yLength = BigIntegerLength(y);
out.writeShort(pLength);
if (pLength == 1) {
if (p.bitLength() == 768) out.writeByte((byte) 1);
else out.writeByte((byte) 2);
} else out.writeBigInteger(p);
out.writeShort(gLength);
if (gLength > 0) out.writeBigInteger(g);
out.writeShort(yLength);
out.writeBigInteger(y);
return out.toByteArray();
}
static byte[] buildDSA(DSAPublicKey key) {
DataByteOutputStream out = new DataByteOutputStream();
BigInteger q = key.getParams().getQ();
BigInteger p = key.getParams().getP();
BigInteger g = key.getParams().getG();
BigInteger y = key.getY();
int t = (p.toByteArray().length - 64) / 8;
out.writeByte(t);
out.writeBigInteger(q);
out.writeBigInteger(p);
out.writeBigInteger(g);
out.writeBigInteger(y);
return out.toByteArray();
}
static byte[] buildRSA(RSAPublicKey key) {
DataByteOutputStream out = new DataByteOutputStream();
BigInteger exponent = key.getPublicExponent();
BigInteger modulus = key.getModulus();
int exponentLength = BigIntegerLength(exponent);
if (exponentLength < 256) out.writeByte(exponentLength);
else {
out.writeByte(0);
out.writeShort(exponentLength);
}
out.writeBigInteger(exponent);
out.writeBigInteger(modulus);
return out.toByteArray();
}