public static XECPublicKey fromBase58EncodedX25519PublicKey(String base58pk) {
        verifyB58InputSmallEnoughToBeX25519Key(base58pk);
        byte[] rawKeyBytes = Base58.codec().decode(base58pk);
        return fromRawX25519PublicKey(rawKeyBytes);
    }
Returns the bytes representing the BigInteger of the X25519 public key EC point U coordinate
security-utils/src/main/java/com/yahoo/security/KeyUtils.java