Java compact representation of ECC PublicKey

Question

java.security.PublicKey#getEncoded() returns X509 representation of key which in case of ECC adds a lot of overhead compared to raw ECC values.

I\'d lik

Answer 1

Here is a BouncyCastle approach I've used to unpack the public key:

public static byte[] extractData(final @NonNull PublicKey publicKey) {
    final SubjectPublicKeyInfo subjectPublicKeyInfo =
            SubjectPublicKeyInfo.getInstance(publicKey.getEncoded());
    final byte[] encodedBytes = subjectPublicKeyInfo.getPublicKeyData().getBytes();
    final byte[] publicKeyData = new byte[encodedBytes.length - 1];

    System.arraycopy(encodedBytes, 1, publicKeyData, 0, encodedBytes.length - 1);

    return publicKeyData;
}