I want to be able to sign my own LOTW entries, without using the provided library (My application is pure Java). Is there a document that explains in enough detail how to do this, assuming of course that I'm provided with a certificate (.tq8 I believe)?


After looking through things for quite some time, and asking around, I was able to find the following, assuming that I can get a copy of the signed certificate from somewhere. There is some more information at this blog article, and this GitHub site.

  1. The log file is done in a format called GAbbI (Global Amateur Interchange). This file format is similar to ADIF, but not quite identical.
  2. The signature is performed using X.509 certificate handling.
  3. The station data is a field in the GAbbI format.
  4. The file is then gzipped, and uploaded to ARRL.

Bottom line is, following the specification given through the linked site is the best bet to getting this to work. X.509 is a standard library, and the GAbbI format is close enough to ADIF that it should be relatively easy to parse through.

A few things to note that are different from the GAbbI spec:

  • All of the data for signing is upper case.
  • The order of fields for the signed data is: CA_PROVINCE, CQZ, GRIDSQUARE, IOTA, ITUZ, US_COUNTY, US_STATE, BAND, BAND_RX, CALL, FREQ, FREQ_RX, MODE, PROP_MODE, QSO_DATE, QSO_TIME, SAT_NAME. Note that station comes first, then QSO data.
  • There are several undocumented fields, including CA_PROVINCE, US_STATE, SIGNDATA, and SIGN_LOTW_V1.0. SIGNDATA is the data signed for the LOTW signature, SIGN_LOTW_V1.0 is the LOTW signature itself. CA__PROVINCE and US_STATE are the Canadian Province and US state.
  • SIGN_LOTW_V1.0 has a :6 after the number of digits. I suspect this is related to the base 64 output.
  • The max space per row is actually 64, not 72 as specified.
  • The character count includes line breaks, and if there is any line breaks, it also counts the last line break. For a single line, it doesn't count the final line break.
  • The signature is signed as SHA1withRSA.

The developer introduction has an overview and links to further resources. If you can link against a C++ library, you can use TrustedQSL to deal with the signing portion, or read the code to understand the process and create a Java version of it.

  • $\begingroup$ I was afraid that might be the answer... Sigh. Hopefully I can figure it out... Might be time to start an open source project... $\endgroup$ – PearsonArtPhoto Feb 18 '14 at 21:09

I'm one of the TrustedQSL developers. We currently have a C library (tqsllib) that you could link against with JNI, but we don't have a Java port of it and aren't really planning to do one.

Most people writing code against LoTW to use the command-line interface to TQSL, explained here: http://www.arrl.org/TrustedQSL/tQSL-help/cmdline.htm

If you decide to do one, feel free to shoot us an email. Be warned - the spec is pretty annoying and if you're trying to make a full-featured application you'll have to deal with creating station locations, which is worse. (The relevant fields are specified in an XML config file that the ARRL provides...)

  • $\begingroup$ I've actually done it, talking a fair bit with Rick and a few others via email in the process. I don't have a full featured library, and in particular the station management could use some work, but it does work. See github.com/kd7uiy/trusted-qsl $\endgroup$ – PearsonArtPhoto May 9 '14 at 1:09

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