test

    std::vector<uint8_t> sig;

    std::vector<uint8_t> cv;

    // Use RSA-PKCS1-SHA256 (0x0401) for maximum compatibility

    // This is the classic RSA signature algorithm, widely supported

    // TLS 1.3 RFC 8446 Section 4.4.3: For RSA signatures, RSASSA-PSS algorithms MUST be used.

    // rsa_pkcs1_* algorithms are NOT allowed for CertificateVerify in TLS 1.3.

    if (_rsa) {

        // For TLS 1.3, we need to use RSA-PKCS1-SHA256 (0x0401)

        // which is RSA signature with PKCS#1 v1.5 padding

        sig = _rsa_sha256_pkcs15_sign(toSign);

        // For TLS 1.3, we MUST use RSA-PSS-RSAE-SHA256 (0x0804)

        // PKCS#1 v1.5 (0x0401) is NOT allowed for CertificateVerify in TLS 1.3

        sig = _rsa_pss_sha256_sign(toSign);

        if (sig.empty())

            throwSSL(NetException::Error, "TLS1.3 CertificateVerify: RSA signature empty");

            throwSSL(NetException::Error, "TLS1.3 CertificateVerify: RSA-PSS signature empty");

        // DEBUG: Log RSA signature details

        fprintf(stderr, "[TLS] RSA-PKCS1-SHA256 signature generated: size=%zu\n", sig.size());

        fprintf(stderr, "[TLS] RSA signature (first 16 bytes): ");

        // DEBUG: Log RSA-PSS signature details

        fprintf(stderr, "[TLS] RSA-PSS-SHA256 signature generated: size=%zu\n", sig.size());

        fprintf(stderr, "[TLS] RSA-PSS signature (first 16 bytes): ");

        for (int i = 0; i < 16 && i < (int)sig.size(); i++)

            fprintf(stderr, "%02x ", sig[i]);

        fprintf(stderr, "\n");

        fprintf(stderr, "[TLS] RSA signature (last 16 bytes): ");

        fprintf(stderr, "[TLS] RSA-PSS signature (last 16 bytes): ");

        for (int i = (int)sig.size() - 16; i < (int)sig.size(); i++)

            if (i >= 0) fprintf(stderr, "%02x ", sig[i]);

        fprintf(stderr, "\n");

        cv.push_back(0x04); cv.push_back(0x01);  // rsa_pkcs1_sha256

        cv.push_back(0x08); cv.push_back(0x04);  // rsa_pss_rsae_sha256 (TLS 1.3 required)

    } else if (_has_ec_key) {

        // Use ECDSA-SHA256 with P-256 curve (0x0403)

        sig = _ecdsa_sha256_sign(toSign);