PGP public key decoding

[Max Lapshin]

https://datatracker.ietf.org/doc/html/rfc4880

1. maybe it is not base64, but radix64 and it could be another thing?
2. is it really ASN?

On Fri, Jul 9, 2021 at 10:09 PM Serge <saleyn@REDACTED> wrote:
>
> Does anyone have an idea how to decode a PGP public key using public_key module?
>
> I am doing this:
>
> 1> {ok, B} = file:read_file(PGPPubKeyFile),
> 2> B1 = re:replace(B, <<"-----BEGIN PGP PUBLIC KEY BLOCK-----">>, <<"-----BEGIN RSA PUBLIC KEY-----">>, [{return, binary}]),
> 3> B2 = re:replace(B1,  <<"-----END PGP PUBLIC KEY BLOCK-----">>,   <<"-----END RSA PUBLIC KEY-----">>,   [{return, binary}]),
> 4> B3 = re:replace(B2,  <<"\n.+(\n-----END)">>,    <<"\\1">>, [{return, binary}]), % Remove checksum
> 5> B4 = re:replace(B3,  <<"\nVersion:.+\n\r?\n">>, <<"\n">>,  [{return, binary}]), % Remove version
> 6> [Entry] = public_key:pem_decode(B4),
> 7> public_key:pem_entry_decode(Entry).
> ** exception error: no match of right hand side value {error,{asn1,{{wrong_tag,{{expected,16},
>                                                                                {got,131097,{131097,<<"\r">>}}}},
>                                                                    [{'OTP-PUB-KEY',match_tags,2,
>                                                                                    [{file,"OTP-PUB-KEY.erl"},{line,23999}]},
>                                                                     {'OTP-PUB-KEY',dec_RSAPublicKey,2,
>                                                                                    [{file,"OTP-PUB-KEY.erl"},{line,2957}]},
>                                                                     {'OTP-PUB-KEY',decode,2,
>                                                                                    [{file,"OTP-PUB-KEY.erl"},{line,1232}]},
>                                                                     {public_key,der_decode,2,
>                                                                                 [{file,"public_key.erl"},{line,318}]},
>                                                                     {erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,689}]},
>                                                                     {shell,exprs,7,[{file,"shell.erl"},{line,686}]},
>                                                                     {shell,eval_exprs,7,[{file,"shell.erl"},{line,642}]},
>                                                                     {shell,eval_loop,3,[{file,"shell.erl"},{line,627}]}]}}}
>     in function  public_key:der_decode/2 (public_key.erl, line 322)