BouncyCastle -- Sending ECDH Derivation and Encoding Vectors in the Clear

Question

So Alice is sending a one-way message to Bob. Alice and Bob both, of course, have their own ECDH private keys, as well as each other's public keys.

I am using BouncyCastle 2.2.1 (BC) in this code. It appears (am I wrong?) that Alice and Bob must have the same Derivation and Encoding vectors (dV and eV) to encrypt a given message from one to the other. I've dug around in the metadata-decompiled code and it appears (again, am I wrong?) that these two values are merely added entropy along with a calculation that has to be made with "my" private and "their" public key anyway.

I adapted my code from this sample, and my google-fu gave out looking for the details on the inputs to IesWithCipherParameters().

MY QUESTION: Are these two values (dV and eV) similar to a block-cipher's initialization vector that is permitted to be sent in the clear?

Here is the complete .NET 6 Console app:

using Org.BouncyCastle.Asn1.X9;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Agreement;
using Org.BouncyCastle.Crypto.Agreement.Kdf;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Macs;
using Org.BouncyCastle.Crypto.Modes;
using Org.BouncyCastle.Crypto.Paddings;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Crypto.Prng;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Security;
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
internal class Program
{
    public static void Main()
    {
        CryptoApiRandomGenerator carng = new CryptoApiRandomGenerator();
        var secureRandom = new SecureRandom(carng);
        var ecParams = ECNamedCurveTable.GetByName("P-256");
    var ecDomainParams = new ECDomainParameters(ecParams.Curve, ecParams.G, ecParams.N, ecParams.H, ecParams.GetSeed());
    var ecKeyGenParams = new ECKeyGenerationParameters(ecDomainParams, secureRandom);
    var ecGenerator = new ECKeyPairGenerator();
    ecGenerator.Init(ecKeyGenParams);

    var kpAlice = ecGenerator.GenerateKeyPair();
    var kpBob = ecGenerator.GenerateKeyPair();

    var messageOriginal = "I am the very model of a modern major general";
    var messageOriginalBytes = Encoding.UTF8.GetBytes(messageOriginal);

    var dV = new byte[8];
    var eV = new byte[8];
    secureRandom.NextBytes(dV);
    secureRandom.NextBytes(eV);

    var ciphertextBytes = Encrypt(kpAlice.Private, kpBob.Public, dV, eV, messageOriginalBytes);

    // we are sending Bob the dV and eV values in the clear. Is that right? Doesn't seem right.
    var decryptedBytes = Decrypt(kpAlice.Public, kpBob.Private, dV, eV, ciphertextBytes);

    var decryptedString = Encoding.UTF8.GetString(decryptedBytes);

    if (messageOriginal == decryptedString)
        Console.WriteLine("it worked");
    else
        Console.WriteLine("it failed");
}

public static byte[] Encrypt(AsymmetricKeyParameter senderPrivate, AsymmetricKeyParameter recipientPublic, byte[] dV, byte[] eV, byte[] plaintextBytes)
{
    //
    // AES with CBC
    //
    BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(
        new CbcBlockCipher(new AesEngine()));
    var iesEngine = new IesEngine(
        new ECDHBasicAgreement(),
        new Kdf2BytesGenerator(new Sha256Digest()),
        new HMac(new Sha1Digest()),
        cipher);
    var p = new IesWithCipherParameters(dV, eV, 64, 128);

    iesEngine.Init(true, senderPrivate, recipientPublic, p);

    var ciphertext = iesEngine.ProcessBlock(plaintextBytes, 0, plaintextBytes.Length);

    return ciphertext;
}

public static byte[] Decrypt(AsymmetricKeyParameter senderPublic, AsymmetricKeyParameter recipientPrivate, byte[] dV, byte[] eV, byte[] ciphertextBytes)
{
    //
    // AES with CBC
    //
    BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(
        new CbcBlockCipher(new AesEngine()));
    var iesEngine = new IesEngine(
        new ECDHBasicAgreement(),
        new Kdf2BytesGenerator(new Sha256Digest()),
        new HMac(new Sha1Digest()),
        cipher);
    var p = new IesWithCipherParameters(dV, eV, 64, 128);

    iesEngine.Init(false, recipientPrivate, senderPublic, p);

    var plaintextBytes = iesEngine.ProcessBlock(ciphertextBytes, 0, ciphertextBytes.Length);

    return plaintextBytes;
}

}