OpenSSL::PKey::PKey#verify

static VALUE
ossl_pkey_verify(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    VALUE digest, sig, data, options;
    const EVP_MD *md = NULL;
    EVP_MD_CTX *ctx;
    EVP_PKEY_CTX *pctx;
    int state, ret;

    GetPKey(self, pkey);
    rb_scan_args(argc, argv, "31", &digest, &sig, &data, &options);
    ossl_pkey_check_public_key(pkey);
    if (!NIL_P(digest))
        md = ossl_evp_get_digestbyname(digest);
    StringValue(sig);
    StringValue(data);

    ctx = EVP_MD_CTX_new();
    if (!ctx)
        ossl_raise(ePKeyError, "EVP_MD_CTX_new");
    if (EVP_DigestVerifyInit(ctx, &pctx, md, /* engine */NULL, pkey) < 1) {
        EVP_MD_CTX_free(ctx);
        ossl_raise(ePKeyError, "EVP_DigestVerifyInit");
    }
    if (!NIL_P(options)) {
        pkey_ctx_apply_options(pctx, options, &state);
        if (state) {
            EVP_MD_CTX_free(ctx);
            rb_jump_tag(state);
        }
    }
#if OSSL_OPENSSL_PREREQ(1, 1, 1) || OSSL_LIBRESSL_PREREQ(3, 4, 0)
    ret = EVP_DigestVerify(ctx, (unsigned char *)RSTRING_PTR(sig),
                           RSTRING_LEN(sig), (unsigned char *)RSTRING_PTR(data),
                           RSTRING_LEN(data));
    EVP_MD_CTX_free(ctx);
    if (ret < 0)
        ossl_raise(ePKeyError, "EVP_DigestVerify");
#else
    if (EVP_DigestVerifyUpdate(ctx, RSTRING_PTR(data), RSTRING_LEN(data)) < 1) {
        EVP_MD_CTX_free(ctx);
        ossl_raise(ePKeyError, "EVP_DigestVerifyUpdate");
    }
    ret = EVP_DigestVerifyFinal(ctx, (unsigned char *)RSTRING_PTR(sig),
                                RSTRING_LEN(sig));
    EVP_MD_CTX_free(ctx);
    if (ret < 0)
        ossl_raise(ePKeyError, "EVP_DigestVerifyFinal");
#endif
    if (ret)
        return Qtrue;
    else {
        ossl_clear_error();
        return Qfalse;
    }
}