jwt-decrypt-rsa-oaep256.c

/**
 *
 * Rhonabwy Javascript Object Signing and Encryption (JOSE) library
 *
 * Example program with a encrypted token using RSA-OAEP-256
 *
 * Copyright 2022 Nicolas Mora <mail@babelouest.org>
 *
 * License MIT
 *
 * To compile with gcc, use the following command:
 * gcc -o jwt-decrypt-rsa-oaep256 jwt-decrypt-rsa-oaep256.c -lrhonabwy
 *
 */

#include <stdio.h>
#include <rhonabwy.h>

const char token[] = "eyJ6aXAiOiJERUYiLCJ0eXAiOiJKV1QiLCJhbGciOiJSU0EtT0FFUC0yNTYiLCJraWQiOiIyMDExLTA0LTI5IiwiZW5jIjoiQTEyOENCQy1IUzI1NiJ9." // Protected Header
                     "l57396lDUn2epeG4h0DxwzJ0cHooWJcCsBxupsN2Znwj1yzRQZdYrHwxTs9eexsb7YM_cTjFJ-lTm0Cj8PBWWkttlTfy5jjzyfCt-pTqCBReJ5kCxmNN0" // Encrypted Key (1)
                       "9xsABx2-6MdoWSTG8afZoqgdv-shqwLRvx-gAOlFqO-RnleveXcWRxxfxZwp3LeJ3iU7sZjIDjiQ4EbnFkvQ2vBNw2WB5mT7xYWi0mlnKsK9CIRWBWy" // Encrypted Key (2)
                       "aC2yjZnOFZIBthY8dWMI4kKehfIPLNTupiq95hvja_Qq-XmuyVk4V9GFPKNzZgMa2MD_zL1SoSqNBevR4MONHbjjGNu-FZ9azIq040tFqDlO-Q."     // Encrypted Key (3)
                     "u8FPu7CC6nJSRLPB0QwXtQ."                                                                                               // Initialization Vector
                     "Zo1ebFtu0Jn0zNTfvouUV3dMs1eNKEddjOrog_zJ5cx0_KyR9nevmIqO2yVC0rZSJW0MO6IpcW3h4gFqt_5iTg."                               // Ciphertext
                     "2_G4OhGzIl9vcgfcP0Yd6g";                                                                                               // Authentication Tag

const char jwk_privkey_rsa_str[] = "{\"kty\":\"RSA\",\"n\":\"0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAtVT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKR"\
                                   "XjBZCiFV4n3oknjhMstn64tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FDW2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHz"\
                                   "u6qMQvRL5hajrn1n91CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINHaQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKg"\
                                   "w\",\"e\":\"AQAB\",\"d\":\"X4cTteJY_gn4FYPsXB8rdXix5vwsg1FLN5E3EaG6RJoVH-HLLKD9M7dx5oo7GURknchnrRweUkC7hT5fJLM0WbFAKNLWY2v"\
                                   "v7B6NqXSzUvxT0_YSfqijwp3RTzlBaCxWp4doFk5N2o8Gy_nHNKroADIkJ46pRUohsXywbReAdYaMwFs9tv8d_cPVY3i07a3t8MN6TNwm0dSawm9v47UiCl3Sk"\
                                   "5ZiG7xojPLu4sbg1U2jx4IBTNBznbJSzFHK66jT8bgkuqsk0GjskDJk19Z4qwjwbsnn4j2WBii3RL-Us2lGVkY8fkFzme1z0HbIkfz0Y6mqnOYtqc0X4jfcKoA"\
                                   "C8Q\",\"p\":\"83i-7IvMGXoMXCskv73TKr8637FiO7Z27zv8oj6pbWUQyLPQBQxtPVnwD20R-60eTDmD2ujnMt5PoqMrm8RfmNhVWDtjjMmCMjOpSXicFHj7"\
                                   "XOuVIYQyqVWlWEh6dN36GVZYk93N8Bc9vY41xy8B9RzzOGVQzXvNEvn7O0nVbfs\",\"q\":\"3dfOR9cuYq-0S-mkFLzgItgMEfFzB2q3hWehMuG0oCuqnb3v"\
                                   "obLyumqjVZQO1dIrdwgTnCdpYzBcOfW5r370AFXjiWft_NGEiovonizhKpo9VVS78TzFgxkIdrecRezsZ-1kYd_s1qDbxtkDEgfAITAG9LUnADun4vIcb6yelx"\
                                   "k\",\"dp\":\"G4sPXkc6Ya9y8oJW9_ILj4xuppu0lzi_H7VTkS8xj5SdX3coE0oimYwxIi2emTAue0UOa5dpgFGyBJ4c8tQ2VF402XRugKDTP8akYhFo5tAA7"\
                                   "7Qe_NmtuYZc3C3m3I24G2GvR5sSDxUyAN2zq8Lfn9EUms6rY3Ob8YeiKkTiBj0\",\"dq\":\"s9lAH9fggBsoFR8Oac2R_E2gw282rT2kGOAhvIllETE1efrA"\
                                   "6huUUvMfBcMpn8lqeW6vzznYY5SSQF7pMdC_agI3nG8Ibp1BUb0JUiraRNqUfLhcQb_d9GF4Dh7e74WbRsobRonujTYN1xCaP6TO61jvWrX-L18txXw494Q_cg"\
                                   "k\",\"qi\":\"GyM_p6JrXySiz1toFgKbWV-JdI3jQ4ypu9rbMWx3rQJBfmt0FoYzgUIZEVFEcOqwemRN81zoDAaa-Bk0KWNGDjJHZDdDmFhW3AN7lI-puxk_m"\
                                   "HZGJ11rxyR8O55XLSe3SPmRfKwZI6yU24ZxvQKFYItdldUKGzO6Ia6zTKhAVRU\",\"alg\":\"RS256\",\"kid\":\"2011-04-29\"}";

int main(void) {
  jwk_t * jwk = NULL;
  jwt_t * jwt = NULL;
  const char * aud, * iss;
  rhn_int_t iat;

  // Import RSA private key to decrypt the JWT
  if (NULL != (jwk = r_jwk_quick_import(R_IMPORT_JSON_STR, jwk_privkey_rsa_str))) {
    // Parse the token into a jwt_t structure
    if (NULL != (jwt = r_jwt_quick_parse(token, R_PARSE_NONE, 0))) {
      // Decrypt the token signature with the private key
      if (r_jwt_decrypt(jwt, jwk, 0) == RHN_OK) {
        // Get token claims to use them in your program
        aud = r_jwt_get_claim_str_value(jwt, "aud");
        iss = r_jwt_get_claim_str_value(jwt, "iss");
        iat = r_jwt_get_claim_int_value(jwt, "iat");
        printf("Token decrypted.\n\n");
        printf("Payload claims\n- aud: %s\n- iss: %s\n- iat %"RHONABWY_INTEGER_FORMAT"\n", aud, iss, iat);
      } else {
        printf("Token not decrypted!\n");
      }
    } // else handle r_jwt_quick_parse error
  } // else handle r_jwk_quick_import error

  // Deallocate the jwt and the jwk used
  r_jwk_free(jwk);
  r_jwt_free(jwt);

  return 0;
}