Dart X509Certificate
last modified October 18, 2026
The X509Certificate class in Dart provides functionality for working
with X.509 certificates. These certificates are used in SSL/TLS connections.
X509Certificate provides read-only access to the fields of an X.509
certificate. Certificate validation is performed by the TLS implementation; the
class itself is part of Dart's dart:io library for secure network
communication.
Basic Definition
X509Certificate represents an X.509 digital certificate. It contains
information about the certificate holder, issuer, validity period, and public key.
Key features include subject/issuer inspection, validity period access, DER and PEM encodings, and the SHA-1 fingerprint. It's essential for secure network communication.
Inspecting a Certificate
Certificates are not instantiated directly with a parser. An X509Certificate is
obtained from a secure connection, for example through
SecureSocket.peerCertificate. The following truncated example
begins with PEM-encoded certificate data.
import 'dart:io';
void main() {
const pemCert = '''
-----BEGIN CERTIFICATE-----
MIIDUTCCAjmgAwIBAgIJAKH9y6A5hQ4AMA0GCSqGSIb3DQEBCwUAMBsxGTAXBgNV
BAMMEHd3dy5leGFtcGxlLmNvbTAeFw0yMzAxMDEwMDAwMDBaFw0yNDAxMDEwMDAw
MDBaMBsxGTAXBgNVBAMMEHd3dy5leGFtcGxlLmNvbTCCASIwDQYJKoZIhvcNAQEB
BQADggEPADCCAQoCggEBALe9z5jZV7v5X9h9X9h9X9h9X9h9X9h9X9h9X9h9X9h9
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