ECIES encryption algorithm parameters

[Luca]

Hello,
I have to use ECIES encyrption scheme to implement this communications scheme, but for me is hard to understand which parameters I must use in ECIESCtxBuilder class to create ECIESEncryptionCtx and ECIESDecryptionCtx classes.
Can you help me?

[Clemens Lang]

You will have to implement some additional features that we do not provide in this library to implement this scheme:

1. We do not currently implement AES-CCM (see https://github.com/bmwcarit/MoCOCrW/blob/openssl1.1/src/mococrw/symmetric_crypto.h#L34-L39)
2. You need to implement the mococrw::KeyDerivationFunction (see src/mococrw/kdf.h) interface for SHA256(S || counter)
3. You need to implement SymmetricCipherI (see https://github.com/bmwcarit/MoCOCrW/blob/openssl1.1/src/mococrw/symmetric_crypto.h#L96) for E(m, k) = m ⊕ k.

Once you have those, you should be able to implement this algorithm using our abstraction by using

ECIESCtxBuilder()
  .setKDF(your_sha256_kdf)
  .setSymmetricCipherFactoryFunction([](const std::vector<uint8_t> &key) -> std::unique_ptr<XORCipher> {
    return XORCipherBuilder().setKey(key).buildEncryptor(); // or buildDecryptor(), but that'll be the same for XOR anyway
  })