diff --git a/src/Sign/JSignService.php b/src/Sign/JSignService.php
index 5c37002..ea7c304 100644
--- a/src/Sign/JSignService.php
+++ b/src/Sign/JSignService.php
@@ -392,42 +392,106 @@ private function pkcs12Read(JSignParam $params): array
     {
         $certificate = $params->getCertificate();
         $password = $params->getPassword();
+
+        $this->clearOpenSslErrors();
+
         if (openssl_pkcs12_read($certificate, $certInfo, $password)) {
             $this->repackCertificateIfPasswordIsUnicode($params, $certInfo['cert'], $certInfo['pkey']);
             return $certInfo;
         }
-        $msg = openssl_error_string();
-        if ($msg === 'error:0308010C:digital envelope routines::unsupported') {
+
+        $errors = $this->getOpenSslErrors();
+        if ($this->hasUnsupportedLegacyAlgorithmError($errors)) {
             $opensslVersion = exec('openssl version');
             if ($opensslVersion === false) {
                 return [];
             }
+
             $tempPassword = tempnam(sys_get_temp_dir(), 'pfx');
             $tempEncriptedOriginal = tempnam(sys_get_temp_dir(), 'original');
             $tempEncriptedRepacked = tempnam(sys_get_temp_dir(), 'repacked');
             $tempDecrypted = tempnam(sys_get_temp_dir(), 'decripted');
+
             if ($tempDecrypted === false || $tempPassword === false || $tempEncriptedOriginal === false || $tempEncriptedRepacked === false) {
                 return [];
             }
+
             file_put_contents($tempPassword, $password);
             file_put_contents($tempEncriptedOriginal, $certificate);
-            $this->safeExec($tempPassword, $tempEncriptedOriginal, $tempDecrypted, $tempEncriptedRepacked);
+
+            $this->safeExec(
+                $tempPassword,
+                $tempEncriptedOriginal,
+                $tempDecrypted,
+                $tempEncriptedRepacked
+            );
+
             $certificateRepacked = file_get_contents($tempEncriptedRepacked);
-            if ($certificateRepacked === false) {
-                return [];
-            }
-            $params->setCertificate($certificateRepacked);
+
             unlink($tempPassword);
             unlink($tempEncriptedOriginal);
             unlink($tempEncriptedRepacked);
             unlink($tempDecrypted);
-            openssl_pkcs12_read($certificateRepacked, $certInfo, $password);
-            $this->repackCertificateIfPasswordIsUnicode($params, $certInfo['cert'], $certInfo['pkey']);
+
+            if ($certificateRepacked === false) {
+                return [];
+            }
+
+            $this->clearOpenSslErrors();
+
+            if (!openssl_pkcs12_read($certificateRepacked, $certInfo, $password)) {
+                $this->getOpenSslErrors();
+                return [];
+            }
+
+            $params->setCertificate($certificateRepacked);
+
+            $this->repackCertificateIfPasswordIsUnicode(
+                $params,
+                $certInfo['cert'],
+                $certInfo['pkey']
+            );
+
             return $certInfo;
         }
+
         return [];
     }
 
+    private function clearOpenSslErrors(): void
+    {
+        while (openssl_error_string() !== false) {
+        }
+    }
+
+    /**
+     * @return list<string>
+     */
+    private function getOpenSslErrors(): array
+    {
+        $errors = [];
+
+        while (($error = openssl_error_string()) !== false) {
+            $errors[] = $error;
+        }
+
+        return $errors;
+    }
+
+    /**
+     * @param list<string> $errors
+     */
+    private function hasUnsupportedLegacyAlgorithmError(array $errors): bool
+    {
+        foreach ($errors as $error) {
+            if (str_contains($error, 'digital envelope routines::unsupported')) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     private function safeExec(
         string $tempPassword,
         string $tempEncriptedOriginal,
diff --git a/tests/Integration/SignPdfTest.php b/tests/Integration/SignPdfTest.php
index f3f6851..cd0e872 100644
--- a/tests/Integration/SignPdfTest.php
+++ b/tests/Integration/SignPdfTest.php
@@ -4,6 +4,7 @@
 
 use Jeidison\JSignPDF\JSignPDF;
 use Jeidison\JSignPDF\Sign\JSignParam;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\TestCase;
 
@@ -29,6 +30,111 @@ private function params(): JSignParam
         return $params;
     }
 
+    private function legacyCertificateParams(): JSignParam
+    {
+        $tempDir = sys_get_temp_dir() . '/jsignpdf-legacy-' . bin2hex(random_bytes(8));
+
+        if (! mkdir($tempDir, 0700, true) && ! is_dir($tempDir)) {
+            $this->fail('Could not create temporary directory.');
+        }
+
+        $key = $tempDir . '/key.pem';
+        $cert = $tempDir . '/cert.pem';
+        $pkcs12 = $tempDir . '/certificate.p12';
+
+        try {
+            exec(
+                sprintf(
+                    'openssl req -x509 -newkey rsa:2048 -nodes -keyout %s -out %s'
+                    . ' -subj %s -days 1 2>&1',
+                    escapeshellarg($key),
+                    escapeshellarg($cert),
+                    escapeshellarg('/CN=JSignPdf Legacy Test')
+                ),
+                $output,
+                $exitCode
+            );
+
+            $this->assertSame(
+                0,
+                $exitCode,
+                'Could not generate test certificate: ' . implode(PHP_EOL, $output)
+            );
+
+            $output = [];
+
+            exec(
+                sprintf(
+                    'openssl pkcs12 -export -legacy -inkey %s -in %s -out %s'
+                    . ' -passout %s 2>&1',
+                    escapeshellarg($key),
+                    escapeshellarg($cert),
+                    escapeshellarg($pkcs12),
+                    escapeshellarg('pass:' . self::PASSWORD)
+                ),
+                $output,
+                $exitCode
+            );
+
+            if ($exitCode !== 0) {
+                $this->markTestSkipped(
+                    'The installed OpenSSL does not support legacy PKCS#12 generation.'
+                );
+            }
+
+            $certificate = file_get_contents($pkcs12);
+            $this->assertNotFalse($certificate);
+        } finally {
+            foreach ([$key, $cert, $pkcs12] as $file) {
+                if (is_file($file)) {
+                    unlink($file);
+                }
+            }
+
+            if (is_dir($tempDir)) {
+                rmdir($tempDir);
+            }
+        }
+
+        $params = JSignParam::instance();
+        $params->setCertificate($certificate);
+        $params->setPdf(file_get_contents(__DIR__ . '/../resources/pdf-test.pdf'));
+        $params->setPassword(self::PASSWORD);
+
+        return $params;
+    }
+
+    #[DataProvider('opensslErrorQueueProvider')]
+    public function testSignWithLegacyCertificateIgnoresPreviousOpenSslErrors(
+        string $errorSource
+    ): void {
+        while (openssl_error_string() !== false) {
+        }
+
+        match ($errorSource) {
+            'x509' => @openssl_x509_read('not-a-certificate'),
+            'private-key' => @openssl_pkey_get_private('not-a-private-key'),
+            'pkcs12' => (function (): void {
+                $certificates = [];
+                @openssl_pkcs12_read('not-a-pkcs12', $certificates, 'wrong-password');
+            })(),
+        };
+
+        $signed = JSignPDF::instance($this->legacyCertificateParams())->sign();
+
+        $this->assertStringStartsWith('%PDF-', $signed);
+        $this->assertStringContainsString('/ByteRange', $signed);
+    }
+
+    public static function opensslErrorQueueProvider(): array
+    {
+        return [
+            'previous X509 error' => ['x509'],
+            'previous private key error' => ['private-key'],
+            'previous PKCS12 error' => ['pkcs12'],
+        ];
+    }
+
     public function testGetVersionReturnsTheInstalledJSignPdf(): void
     {
         $version = JSignPDF::instance($this->params())->getVersion();