Empty exception when parsing Go paseto v2 public

[hazcod]

Hi! Thank you for the library.

I am trying to parse a public (v2) paseto token generated by https://github.com/o1egl/paseto . However, an empty exception is returned when parsing.

        try:
            parsed = paseto.parse(
                key=self.tokenSecretKey,
                purpose='local',
                token=tokenValue,
                encoder=paseto.JsonEncoder, 
                validate=False,
                rules=None,
                required_claims=[
                    '1',
                    '2',
                    '3',
                ]
            )
        except Exception as e:
            raise ValueError("token decrypt failed: " + str(e))

Returns: token decrypt failed:.

Generator:

            now := time.Now()
                        pasetoV2 := paseto.NewV2()
            jsonToken := paseto.JSONToken{
                Audience:   "",
                Subject:    "",
                Issuer:     "foo",
                Jti:        strconv.FormatUint(ID, 10),
                Expiration: now.AddDate(0, 0, tokenExpiryDays),
                IssuedAt:   now,
                NotBefore:  now,
            }

            jsonToken.Set("1", testUUID)
            jsonToken.Set("2", strconv.FormatUint(ID, 10))
            jsonToken.Set("3", user.Name)

            token, err := pasetoV2.Encrypt(cryptoKeyBytes, jsonToken, nil)
            if err != nil { ... }

[rlittlefield]

If you have a public token, try passing in purpose='public' to the paseto.parse call. If you pass "local", it will be expecting a local type token.

[rlittlefield]

Not sure if you had any luck with this. I'm guessing this is because we don't have messages for some of these exceptions.

I've added this issue to track this: https://github.com/rlittlefield/pypaseto/issues/18

If you are having trouble figuring out which exception before I get a fix in for this, you can to str(type(e)), which should give you the name of the exception class.