AES/CFB8 with OpenSSL - c++

Question

I recently started a small side-project to recreate the Minecraft Server in C++ but I stumbled on a problem.
I need to use the AES/CFB8 Cipher according to this link with continuous updating (not finished and restarted every packet).
I surfed trough the internet to try to find a proper solution but could not figure out one that was actually working or it was using the command line interface.
Any help is welcomed !
Cipher.h
class Cipher {
public:
enum CipherType {
ENCRYPT,
DECRYPT
};
private:
EVP_CIPHER_CTX* ctx;
CipherType type;
bool hasFinished;
public:
Cipher(const char* key, const char* iv, CipherType type);
~Cipher();
int update(char* in, int inl, char* out);
int final(char* out);
int getMinimumBufLength(int size);
};
Cipher.cpp
Cipher::Cipher(const char* key, const char* iv, CipherType type) : type(type), hasFinished(false)
{
ctx = EVP_CIPHER_CTX_new();
EVP_CIPHER_CTX_init(ctx);
if(type == CipherType::ENCRYPT)
EVP_EncryptInit_ex(ctx, EVP_aes_256_cfb8(), nullptr, (unsigned char*)key, (unsigned char*)iv);
else
EVP_DecryptInit_ex(ctx, EVP_aes_256_cfb8(), nullptr, (unsigned char*)key, (unsigned char*)iv);
}
Cipher::~Cipher()
{
EVP_CIPHER_CTX_free(ctx);
}
int Cipher::getMinimumBufLength(int size)
{
return type == CipherType::DECRYPT ? size : size + AES_BLOCK_SIZE * 2;
}
int Cipher::update(char* in, int inl, char* out)
{
int len;
EVP_CipherUpdate(ctx, (unsigned char*)out, &len, (unsigned char*)in, inl);
return len;
}
int Cipher::final(char* out)
{
int len;
EVP_EncryptFinal_ex(ctx, (unsigned char*)out, &len);
return len;
}
Cipher-test.cpp
TEST_CASE("Cipher AES/CFB8")
{
char* key = "AAAAAAAAAZEFRGUINJFKDFIVJ";
char* iv = "AUJVFEUB";
Cipher encryptionCipher(key, iv, Cipher::CipherType::ENCRYPT);
Cipher decryptionCipher(key, iv, Cipher::CipherType::DECRYPT);
std::string data = "Hello World ! This is some soon to be encrypted string !";
char encData[encryptionCipher.getMinimumBufLength(data.size() + 1)];
int outLen = encryptionCipher.update(data.data(), data.size() + 1, encData);
int fLen = encryptionCipher.final(encData + outLen);
CHECK(data != std::string(encData));
char decData[decryptionCipher.getMinimumBufLength(outLen + fLen)];
outLen = decryptionCipher.update(encData, outLen + fLen, decData);
decryptionCipher.final(decData + outLen);
CHECK(data == std::string(decData));
}
Thanks in advance
EDIT: I am just wondering if there was a need for supplementary code because of the "continuous" aspect of the Cipher.