[lamps] Re: New Individual Draft: Manufacturer-Signed CA Certificate Distribution for EST and EST-coaps Deployments

[Franklin Ferreira de Lima <[e-mail]>]

/**
 * @file IluminaTecnica_AC_on_DC.ino
 * @brief Controlled high-frequency AC ripple superposition on a stable DC
bias for LED testing.
 * @note USE WITH CAUTION. Ensure your hardware driver circuit can handle
high-frequency PWM switching.
 */

// Hardware Configuration
const int LED_DRIVER_PIN = 9; // PWM output pin connected to the MOSFET
gate/LED driver
const int PWM_FREQUENCY = 25000; // 25 kHz frequency to keep AC ripple out
of the audible and visible spectrum

// Signal Parameterization (0 - 255 for standard 8-bit PWM)
const int DC_BIAS_LEVEL = 128; // The permanent stable DC offset (approx
50% voltage baseline)
const int AC_AMPLITUDE = 30; // The peak amplitude of the superimposed AC
wave (Keep low for safety!)

// Math variables
float angularFrequency = 0.0;
const float WAVE_SPEED = 0.05; // Speed of the AC wave alternation

void setup() {
  // Initialize communication for debugging
  Serial.begin(115200);

  // Configure hardware pin
  pinMode(LED_DRIVER_PIN, OUTPUT);

  // Technical Note: If using an ESP32, you would set up ledcAttachChannel
here
  // to enforce a strict 25kHz switching frequency to protect the LED
infrastructure.
  Serial.println(F("[ILUMINA TÉCNICA] System initialized. DC Bias active.
Superimposing AC component..."));
}

void loop() {
  // 1. Calculate the instantaneous sinusoidal AC component
  // Sine outputs a value between -1.0 and 1.0
  float ac_component = sin(angularFrequency) * AC_AMPLITUDE;

  // 2. Superimpose the AC wave onto the stable DC baseline
  int final_signal_output = DC_BIAS_LEVEL + (int)ac_component;

  // 3. Safety Check: Hard-clamp boundaries to prevent driver
over-saturation or reverse polarity
  final_signal_output = constraintCheck(final_signal_output);

  // 4. Output the combined signal to the physical layer
  analogWrite(LED_DRIVER_PIN, final_signal_output);

  // Increment time/angle for the AC frequency
  angularFrequency += WAVE_SPEED;
  if (angularFrequency >= 2 * PI) {
    angularFrequency = 0.0; // Reset phase to prevent float overflow
  }

  // Tiny delay to control loop execution speed during hardware debugging
  delay(5);
}

/**
 * @brief Safety boundary check to protect physical LED components from
extreme electrical values.
 */
int constraintCheck(int calculatedValue) {
  const int ABSOLUTE_MAX_SAFE_LIMIT = 200; // Safeguard limit to protect
against peak current degradation
  const int ABSOLUTE_MIN_SAFE_LIMIT = 40; // Ensure the LED never fully
turns off (maintains DC bias)

  if (calculatedValue > ABSOLUTE_MAX_SAFE_LIMIT) return
ABSOLUTE_MAX_SAFE_LIMIT;
  if (calculatedValue < ABSOLUTE_MIN_SAFE_LIMIT) return
ABSOLUTE_MIN_SAFE_LIMIT;
  return calculatedValue;
}

Em qui., 8 de out. de 2026, 12:29, Mittal, Narinder <Narinder.Mittal=
[e-mail]> escreveu:

> Hi,
>
> I wanted to follow up on the individual draft we shared on September 25
> describing manufacturer-signed CA certificate distribution for EST and
> EST-coaps deployments:
>
> draft-mittal-est-coap-ca-certs-00
> <https://datatracker.ietf.org/doc/draft-mittal-est-coap-ca-certs/>
>
> We would appreciate any feedback from the LAMPS community. This would be
> very helpful as we prepare the next revision.
>
> Thanks
>
> ​
> *Narinder Mittal*
> Principal Engineer, System Architecture
> *CISSP, CCSP, CISM*
> ​*Email:* [e-mail]
> landisgyr.com <https://www.landisgyr.com>
> ​
>
> <https://x.com/landisgyr>
>
> <https://www.youtube.com/@LandisGyrOfficial>
>
> <https://www.linkedin.com/company/landis/>
>
>
>
> *From:* Mittal, Narinder
> *Sent:* Friday, September 25, 2026 12:44 PM
> *To:* '[e-mail]' <[e-mail]>
> *Cc:* Hett, Chris <[e-mail]>
> *Subject:* New Individual Draft: Manufacturer-Signed CA Certificate
> Distribution for EST and EST-coaps Deployments
>
>
>
> Hello,
>
>
>
> Chris Hett and I have submitted an individual draft describing a
> manufacturer-signed mechanism for distributing operational CA certificates
> to constrained EST/EST-coaps clients prior to EST enrollment:
>
>
>
> draft-mittal-est-coap-ca-certs-00 -
> https://datatracker.ietf.org/doc/draft-mittal-est-coap-ca-certs/
>
>
>
> The draft is intended to address deployments where operational trust
> anchors are not known at manufacturing time and devices are provisioned
> only with a manufacturer trust anchor. The mechanism uses a
> manufacturer-signed CMS object containing an operational CA certificate
> bundle. Devices validate the CMS signature using a manufacturer trust
> anchor provisioned during manufacturing before installing the operational
> trust anchors. The draft is intended as an Informational deployment
> mechanism and does not modify RFC 7030 or RFC 9148.
>
>
>
> The draft was motivated by utility-industry deployment requirements and
> has received early interest from participants involved in GEISA
> discussions.
>
>
>
> We would appreciate feedback on:
>
>    - problem statement
>    - trust model
>    - interaction with existing EST bootstrap procedures
>    - applicability to constrained deployments
>
>
>
> Thanks,
>
> Narinder Mittal
>
> Chris Hett
>
>
>
> ​
> *Narinder Mittal*
> Principal Engineer, System Architecture
> *CISSP, CCSP, CISM*
> ​*Email:* [e-mail]
> landisgyr.com <https://www.landisgyr.com>
> ​
>
> <https://x.com/landisgyr>
>
> <https://www.youtube.com/@LandisGyrOfficial>
>
> <https://www.linkedin.com/company/landis/>
>
>
>
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Franklin Ferreira de Lima