ccp_copy_and_save_keypart
ret = ccp_copy_and_save_keypart(&ctx->u.rsa.n_buf, &ctx->u.rsa.n_len,
ret = ccp_copy_and_save_keypart(&ctx->u.rsa.e_buf, &ctx->u.rsa.e_len,
ret = ccp_copy_and_save_keypart(&ctx->u.rsa.d_buf,