help using /usr/bin/netpgp

[Henry <nbsd4ever%gmail.com@localhost>]

I'm not having any luck using /usr/bin/netpgp to verify the
integrity of downloaded files.

I wasn't sure from the man page what the correct command line would
be, but using the format I used in the past with gpg,
`netpgp --verify gnupg-2.2.1.tar.bz2.sig gnupg-2.2.1.tar.bz2`
failed with:
        "gnupg-2.2.1.tar.bz2.sig": verification failure: 0 invalid signatures, 2
 unknown signatures
        "gnupg-2.2.1.tar.bz2": No signatures found - is this a signed file?

I thought maybe it failed because I hadn't imported a public key yet,
so I downloaded the public keys and named one of them "publickey.txt".
I then ran `netpgpkeys --import-key publickey.txt`, but got:
        Can't free 545 (0x221)
        Can't free 547 (0x223)
        Error: Subpacket too long
        Can't free 545 (0x221)
        Error: Subpacket too long
        /usr/src/crypto/external/bsd/netpgp/lib/netpgp/../../dist/src/lib/packet
-parse.c:1793: PGP_E_PROTO_UNKNOWN_SS, Unknown signature subpacket type (33)
        /usr/src/crypto/external/bsd/netpgp/lib/netpgp/../../dist/src/lib/packet
-parse.c:1793: PGP_E_PROTO_UNKNOWN_SS, Unknown signature subpacket type (35)
        /usr/src/crypto/external/bsd/netpgp/lib/netpgp/../../dist/src/lib/packet
-parse.c:1793: PGP_E_PROTO_UNKNOWN_SS, Unknown signature subpacket type (33)
        Cannot import key from file publickey.txt

Help on how to proceed much appreciated.  TIA

Henry