did_helper.c

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/*
   This file is part of GNUnet
   Copyright (C) 2010-2015 GNUnet e.V.
 
   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.
 
   GNUnet is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Affero General Public License for more details.
 
   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
   SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_namestore_service.h"
#include "gnunet_gns_service.h"
#include "gnunet_gnsrecord_lib.h"
#include "did_helper.h"
#include "jansson.h"
 
#define STR_INDIR(x) #x
#define STR(x) STR_INDIR (x)
 
char*
DID_pkey_to_did (struct GNUNET_CRYPTO_PublicKey *pkey)
{
  char *pkey_str;
  char *did_str;
 
  pkey_str = GNUNET_CRYPTO_public_key_to_string (pkey);
  GNUNET_asprintf (&did_str, "%s%s",
                   GNUNET_DID_METHOD_PREFIX,
                   pkey_str);
 
  GNUNET_free (pkey_str);
  return did_str;
}
 
char*
DID_identity_to_did (struct GNUNET_IDENTITY_Ego *ego)
{
  struct GNUNET_CRYPTO_PublicKey pkey;
 
  GNUNET_IDENTITY_ego_get_public_key (ego, &pkey);
  return DID_pkey_to_did (&pkey);
}
 
enum GNUNET_GenericReturnValue
DID_did_to_pkey (const char *did, struct GNUNET_CRYPTO_PublicKey *pkey)
{
  char pkey_str[MAX_DID_SPECIFIC_IDENTIFIER_LENGTH + 1]; /* 0-term */
 
  if ((1 != (sscanf (did,
                     GNUNET_DID_METHOD_PREFIX "%"
                     STR (MAX_DID_SPECIFIC_IDENTIFIER_LENGTH)
                     "s", pkey_str))) ||
      (GNUNET_OK != GNUNET_CRYPTO_public_key_from_string (pkey_str, pkey)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Could not decode given DID: %s\n",
                did);
    return GNUNET_NO;
  }
 
  return GNUNET_OK;
}
 
char *
DID_key_convert_gnunet_to_multibase_base64 (struct
                                           GNUNET_CRYPTO_PublicKey *
                                           pkey)
{
  struct GNUNET_CRYPTO_EddsaPublicKey pubkey = pkey->eddsa_key;
 
  // This is how to convert out pubkeys to W3c Ed25519-2020 multibase (base64url no padding)
  char *pkey_base_64;
  char *pkey_multibase;
  char pkx[34];
 
  pkx[0] = 0xed;
  pkx[1] = 0x01;
  memcpy (pkx + 2, &pubkey, sizeof (pubkey));
  GNUNET_STRINGS_base64url_encode (pkx, sizeof (pkx), &pkey_base_64);
  GNUNET_asprintf (&pkey_multibase, "u%s", pkey_base_64);
 
  GNUNET_free (pkey_base_64);
  return pkey_multibase;
}
 
char *
DID_pkey_to_did_document (struct GNUNET_CRYPTO_PublicKey *pkey)
{
 
  /* FIXME-MSC: This is effectively creating a DID Document default template for
   * the initial document.
   * Maybe this can be refactored to generate such a template for an identity?
   * Even if higher layers add/modify it, there should probably still be a
   * GNUNET_DID_document_template_from_identity()
   */
 
  char *did_str;
  char *verify_id_str;
  char *pkey_multibase_str;
  char *didd_str;
  json_t *didd_json;
 
  did_str = DID_pkey_to_did (pkey);
  GNUNET_asprintf (&verify_id_str, "%s#key-1", did_str);
 
  pkey_multibase_str = DID_key_convert_gnunet_to_multibase_base64 (pkey);
 
  didd_json = json_pack (
    "{s:[ss], s:s, s:[{s:s, s:s, s:s, s:s}], s:[s], s:[s]}",
    "@context",
    "https://www.w3.org/ns/did/v1",
    "https://w3id.org/security/suites/ed25519-2020/v1",
    "id",
    did_str,
    "verificationMethod",
    "id",
    verify_id_str,
    "type",
    "Ed25519VerificationKey2020",
    "controller",
    did_str,
    "publicKeyMultibase",
    pkey_multibase_str,
    "authentication",
    "#key-1",
    "assertionMethod",
    "#key-1");
 
  // Encode DID Document as JSON string
  didd_str = json_dumps (didd_json, JSON_INDENT (2));
 
  // Free
  GNUNET_free (did_str);
  GNUNET_free (verify_id_str);
  GNUNET_free (pkey_multibase_str);
  json_decref (didd_json);
 
  return didd_str;
}
 
char *
DID_identity_to_did_document (struct GNUNET_IDENTITY_Ego *ego)
{
  struct GNUNET_CRYPTO_PublicKey pkey;
 
  GNUNET_IDENTITY_ego_get_public_key (ego, &pkey);
  return DID_pkey_to_did (&pkey);
}