private static Bytes toBytes64(final byte[] backing) {
    if (backing.length == BYTE_LENGTH) {
      return Bytes.wrap(backing);
    } else if (backing.length > BYTE_LENGTH) {
      return Bytes.wrap(backing, backing.length - BYTE_LENGTH, BYTE_LENGTH);
    } else {
      final MutableBytes res = MutableBytes.create(BYTE_LENGTH);
      Bytes.wrap(backing).copyTo(res, BYTE_LENGTH - backing.length);
      return res;
    }
  }
Create secp public key.

@param privateKey the private key
@param curve the curve
@param algorithm the algorithm
@return the secp public key
crypto/algorithms/src/main/java/org/hyperledger/besu/crypto/SECPPublicKey.java