void ECP::EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const
{
if (P.identity)
NullStore().TransferTo(bt, EncodedPointSize(compressed));
else if (compressed)
{
bt.Put(2 + P.y.GetBit(0));
P.x.Encode(bt, GetField().MaxElementByteLength());
}
else
{
unsigned int len = GetField().MaxElementByteLength();
bt.Put(4); // uncompressed
P.x.Encode(bt, len);
P.y.Encode(bt, len);
}
}
void EC2N::EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const
{
if (P.identity)
NullStore().TransferTo(bt, EncodedPointSize(compressed));
else if (compressed)
{
bt.Put(2 + (!P.x ? 0 : m_field->Divide(P.y, P.x).GetBit(0)));
P.x.Encode(bt, m_field->MaxElementByteLength());
}
else
{
unsigned int len = m_field->MaxElementByteLength();
bt.Put(4); // uncompressed
P.x.Encode(bt, len);
P.y.Encode(bt, len);
}
}
void EC2N::EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const
{
if (P.identity)
memset(encodedPoint, 0, EncodedPointSize(compressed));
else if (compressed)
{
encodedPoint[0] = 2 + (!P.x ? 0 : m_field->Divide(P.y, P.x).GetBit(0));
P.x.Encode(encodedPoint+1, m_field->MaxElementByteLength());
}
else
{
unsigned int len = m_field->MaxElementByteLength();
encodedPoint[0] = 4; // uncompressed
P.x.Encode(encodedPoint+1, len);
P.y.Encode(encodedPoint+1+len, len);
}
}
void EC2N::DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const
{
SecByteBlock str(EncodedPointSize(compressed));
EncodePoint(str, P, compressed);
DEREncodeOctetString(bt, str);
}
void ECP::EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const
{
ArraySink sink(encodedPoint, EncodedPointSize(compressed));
EncodePoint(sink, P, compressed);
assert(sink.TotalPutLength() == EncodedPointSize(compressed));
}
void EC2N::EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const
{
ArraySink sink(encodedPoint, EncodedPointSize(compressed));
EncodePoint(sink, P, compressed);
CRYPTOPP_ASSERT(sink.TotalPutLength() == EncodedPointSize(compressed));
}