# Appendix A — ARRL Logbook of the World (LOTW)

# Digital Signature Rule, Version 1.0

## Signed Fields

### REC_TYPE

### tSTATION

### tCONTACT

Field |  | Field |
CALL | Required | BAND | Required
CONT | Optional | CALL | Required
CQZ | Optional | FREQ | Optional
CZ_DISTRICT | Optional | MODE | Required
DOK | Optional | QSO_DATE | Required
DXCC | Required | QSO_TIME | Required
GRIDSQUARE | Optional | RST_SENT | Optional
IOTA | Optional |  |
ITUZ | Optional |  |
JA_CITY | Optional |  |
JA_GUN | Optional |  |
NZ_COUNTY | Optional |  |
REPEATER | Optional |  |
SAT_NAME | Optional |  |
SAT_MODE | Optional |  |
SDOK | Optional |  |
SK_DISTRICT | Optional |  |
STATION_TYPE | Optional |  |
SUB_GOV1 | Optional |  |
SUB_GOV2 | Optional |  |
SUB_GOV3 | Optional |  |
TX_PWR | Optional |  |
US_COUNTY | Optional |  |
WAE | Optional |  |

## Construction of the Signed Material

1. The object to be signed is a character string that shall be created by concatenation of the field_values of the fields designated for signing under this rule (see above) that are present in a virtual QSL record.
2. No white space or other delimiters shall be inserted between adjacent field_values when forming the string.
3. The order in which field_values are placed in the string shall be as follows:

1. First are the field_values from the tSTATION record in order of an alphanumeric sorting of the field_name corresponding to each field_value.
2. The tSTATION field_values are followed by the field_values from the tCONTACT record again in order of an alphanumeric sorting of the field_name corresponding to each field_value.
3. In the event that the same field_name occurs more than once within a record, the relative ordering of the field_values for a non-unique field_name is determined by an alphanumeric sorting of these field_values.

4. No place holders or other padding shall be inserted in the string to account for optional fields that are not present in the record being signed.
5. A terminating null, a byte count or any other implementation dependent string delimiter or string length indicator shall not be considered to be a part of the character string being signed.

## Signature

#### Key Type

#### Rivest, Shamir & Abelson Public Key Algorithm (RSA);

#### see ANSI X9.31-1998.

Key Length | 1024 bits
Message Digest Algorithm | Secure Hash Algorithm (SHA-1); see FIPS-180-1.