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Porsche Charging Data Format (PCDF)

The Porsche Charging Data Format (PCDF) is a compact, line-oriented transparency data format for a single signed DC charging session. It is built from fixed-order key-value fields after the OBIS-like prefix 128.8.0.

Chargy treats PCDF as a single signed session data set. Unlike OCMF, PCDF does not contain a JSON payload and it does not normally provide separate signed START and STOP meter readings. The signed record contains the relevant session timestamps, flags, energy value, meter identity, embedded public key and ECDSA signature.

General Structure

A PCDF record is one string:

128.8.0(ST:<value>)(CT:<value>)(CD:<value>)(TV:<value>)(BV:<value>)(CSC:<value>)(SP:<value>)(RV:<value>)(SI:<value>)(CS:<value>)(HW:<value>)(DT:<value>)(PK:<value>)(SG:<value>)

All fields are mandatory and must appear in this exact order.

The parser also accepts optional STX and ETX control characters around the record:

\x02128.8.0(...)(SG:...)\x03

Signed Payload

The signed payload is the exact UTF-8 byte sequence from the 128.8.0 prefix up to, but not including, the (SG: field.

128.8.0(ST:260101120000)...(DT:0)(PK:04...)

The signature is calculated over:

SHA-256(signedPayload)

and verified as:

ECDSA over secp256r1 / prime256v1, DER encoded signature

The public key in PK is embedded in the PCDF record itself. Chargy accepts the raw uncompressed EC point:

04 || X-coordinate || Y-coordinate

This is 65 bytes, encoded as 130 hexadecimal characters. For public key files, Chargy can also normalize a DER/SPKI encoded P-256 public key to the raw point before comparing it to the embedded key.

Fields

Field Name Format Notes
ST Start Time YYMMDDHHmmss UTC-style timestamp. Year must be 19 or later.
CT Current/Stop Time YYMMDDHHmmss Must be greater than or equal to ST.
CD Charging Duration HHmmss Hours 00-99, minutes and seconds 00-59.
TV Time Validity 0 or 1 1 means the timestamp is valid.
BV Billing Validity 0 or 1 0 means billing is not possible and is treated as an invalid session.
CSC Charging Session Counter decimal integer Must be non-negative.
SP Stop Present 0 or 1 1 means the final session data is present. 0 is invalid for billing verification.
RV Reading Value NNNN.NNN*kWh Energy value in kWh with exactly 4 integer and 3 fractional digits.
SI Session Info <idTag>*<type>*<transactionId> type is one character in the range 1-5.
CS Software Checksum 8 hexadecimal chars Stored as lowercase internally.
HW Hardware Serial 11 chars Meter hardware serial.
DT DC Meter Type decimal integer 0 means PES DCMeter EU, other values are currently unknown.
PK Public Key 130 hexadecimal chars Uncompressed P-256 EC point, beginning with 04.
SG Signature hexadecimal DER ASN.1 DER encoded ECDSA signature.

Session Info Types

The second component of SI is preserved as a string. The known values are:

Type Meaning
1 RFID
2 EMAID
3 Credit card
4 Remote
5 NFC

Example:

(SI:DE-PORSCHE-EMAID*2*tx-2026-00042)

Complete Shape Example

This example is shortened in the PK and SG fields for readability. A real record must contain the full 130-character public key and the complete DER signature.

128.8.0(ST:260101120000)(CT:260101123045)(CD:003045)(TV:1)(BV:1)(CSC:42)(SP:1)(RV:0042.125*kWh)(SI:DE-PORSCHE-EMAID*2*tx-2026-00042)(CS:513f627b)(HW:PDCM1234567)(DT:0)(PK:04aabbccddeeff00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff00112233445566778899)(SG:3045022100...)

Variant Examples

RFID Session

An RFID-authenticated session uses SI:<idTag>*1*<transactionId>.

128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:1)(CSC:1)(SP:1)(RV:0003.276*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:3045...)

EMAID Session

An EMAID-authenticated session uses SI:<emaid>*2*<transactionId>.

128.8.0(ST:260601081500)(CT:260601090245)(CD:004745)(TV:1)(BV:1)(CSC:18)(SP:1)(RV:0028.750*kWh)(SI:DE8PORC1234567890*2*tx-emaid-00018)(CS:a1b2c3d4)(HW:PDCM1234567)(DT:0)(PK:04...)(SG:3044...)

Remote Authorization

Remote authorization uses session info type 4.

128.8.0(ST:260701211000)(CT:260701215800)(CD:004800)(TV:1)(BV:1)(CSC:105)(SP:1)(RV:0017.925*kWh)(SI:remote-user-42*4*remote-tx-105)(CS:7f12ab90)(HW:98765432109)(DT:0)(PK:04...)(SG:3046...)

NFC Authorization

NFC authorization uses session info type 5.

128.8.0(ST:260802073015)(CT:260802081500)(CD:004745)(TV:1)(BV:1)(CSC:106)(SP:1)(RV:0011.400*kWh)(SI:nfc-token-7*5*nfc-tx-106)(CS:0000abcd)(HW:98765432109)(DT:0)(PK:04...)(SG:3045...)

Zero Energy Session

The value format allows 0000.000*kWh. Whether such a record is acceptable for billing depends on the surrounding business context, but the PCDF field itself is syntactically valid.

128.8.0(ST:260901101500)(CT:260901101700)(CD:000200)(TV:1)(BV:1)(CSC:107)(SP:1)(RV:0000.000*kWh)(SI:testuser*1*zero-energy-107)(CS:abcdef12)(HW:12345678901)(DT:0)(PK:04...)(SG:3044...)

Unknown Meter Type

DT:0 is currently known as PES DCMeter EU. Other values are parsed and kept, but displayed as unknown meter types.

128.8.0(ST:261001120000)(CT:261001124500)(CD:004500)(TV:1)(BV:1)(CSC:108)(SP:1)(RV:0020.000*kWh)(SI:testuser*1*unknown-meter-108)(CS:1234abcd)(HW:12345678901)(DT:99)(PK:04...)(SG:3045...)

STX/ETX Wrapped Record

Some transports wrap the payload with ASCII control characters. Chargy strips a leading STX (0x02) and a trailing ETX (0x03) before parsing.

\x02128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:1)(CSC:1)(SP:1)(RV:0003.276*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:3045...)\x03

Quoted Record

Some sources provide the complete PCDF string as a quoted text value. Chargy accepts this form as well.

"128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:1)(CSC:1)(SP:1)(RV:0003.276*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:3045...)"

Invalid but Signed Variants

The following records can be cryptographically signed but are not considered valid charging transparency data for billing verification.

Billing Invalid

BV:0 means that billing is not possible because the DC meter reported an error.

128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:0)(CSC:1)(SP:1)(RV:0003.276*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:3045...)

Stop Data Missing

SP:0 means that the final session data is missing. Chargy reports this as an invalid session.

128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:1)(CSC:1)(SP:0)(RV:0003.276*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:3045...)

Tampered Reading Value

Changing any character in the signed payload, for example RV, must invalidate the signature.

128.8.0(ST:260501162017)(CT:260501162234)(CD:000217)(TV:1)(BV:1)(CSC:1)(SP:1)(RV:0003.277*kWh)(SI:55*1*959bff1e-7164-4132-b783-4a9feed1bfee)(CS:513f627b)(HW:12345678901)(DT:0)(PK:04...)(SG:original-signature-from-0003.276-record)

Validation Notes

Chargy distinguishes parsing, semantic validation and cryptographic verification:

  1. Parsing checks the prefix, field order and the presence of all mandatory fields.
  2. Validation checks timestamp ranges, flags, reading value format, session information, software checksum length, hardware serial length, public key shape and DER signature shape.
  3. Verification checks the embedded public key and the ECDSA signature over the signed payload.

When an external public key is supplied, it must match the embedded PK value byte-for-byte after normalization. Otherwise the record is rejected with a wrong public-key error before the signature is trusted.