pretty_key_id
printf("Subject key identifier: %s\n", pretty_key_id(ski));
printf("Subject key identifier: %s\n", pretty_key_id(p->ski));
pretty_key_id(p->aki));
printf("Authority key identifier: %s\n", pretty_key_id(p->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));
printf("Subject key identifier: %s\n", pretty_key_id(c->ski));
printf("Authority key identifier: %s\n", pretty_key_id(c->aki));