user71151: How to create a bouncy castle ECPoint from a raw private key hex string?  I am getting a private key using the 'dumpprivkey' RPC and removing the header byte and the 4 bytes of checksum + 1 byte of discriminator trailer bytes, resulting in a 32 byte raw key LIKE this example (this sample comes from here).  It causes the following exception.  Decoding public keys this way does not have this problem.
This is the code:
public static void main(String[] args) {
    String priv_key = "E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262"; 
    BigInteger value = new BigInteger(priv_key, 16);
    ECCurve BITCOIN_CURVE = new SecP256K1Curve();
    ECPoint point = BITCOIN_CURVE.decodePoint(value.toByteArray());
}

But it results in this exception:
Exception in thread "main" java.lang.IllegalArgumentException: Incorrect length for infinity encoding
    at org.bouncycastle.math.ec.ECCurve.decodePoint(Unknown Source)
    at Btc.main(Btc.java:19)


user71151: A raw private key is not on the elliptic curve, so there will be no ECPoint.  It is a random number as described here.

71151: <p>How to create a bouncy castle ECPoint from a raw private key hex string?  I am getting a private key using the 'dumpprivkey' RPC and removing the header byte and the 4 bytes of checksum + 1 byte of discriminator trailer bytes, resulting in a 32 byte raw key LIKE this example (this sample comes from <a href="https://en.bitcoin.it/wiki/Private_key" rel="nofollow noreferrer">here</a>).  It causes the following exception.  Decoding public keys this way does not have this problem.</p>

<p>This is the code:</p>

<pre><code>public static void main(String[] args) {
    String priv_key = "E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262"; 
    BigInteger value = new BigInteger(priv_key, 16);
    ECCurve BITCOIN_CURVE = new SecP256K1Curve();
    ECPoint point = BITCOIN_CURVE.decodePoint(value.toByteArray());
}
</code></pre>

<p>But it results in this exception:</p>

<pre><code>Exception in thread "main" java.lang.IllegalArgumentException: Incorrect length for infinity encoding
    at org.bouncycastle.math.ec.ECCurve.decodePoint(Unknown Source)
    at Btc.main(Btc.java:19)
</code></pre>
 71151: <p>A raw private key is not on the elliptic curve, so there will be no ECPoint.  It is a random number as described <a href="https://bitcoin.stackexchange.com/a/79142/71151">here</a>.</p>
