从私钥派生ECDSA公钥

因此，过了一会儿，我想出了一个解决方案，并决定将其发布，以防其他人遇到与我相同的问题：

KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", "BC");    ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("secp256k1");    ECPoint Q = ecSpec.getG().multiply(((org.bouncycastle.jce.interfaces.ECPrivateKey) this.privateKey).getD());    ECPublicKeySpec pubSpec = new ECPublicKeySpec(Q, ecSpec);    PublicKey publicKeyGenerated = keyFactory.generatePublic(pubSpec);    this.publicKey = publicKeyGenerated;

编辑：删除了根据@MaartenBodewes注释解码ECPoint的代码。