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Convertir une chaîne au format PEM en Java.security.cert.X509Certificate

Comment créer un Java.security.cert.X509Certificate instance d'une chaîne au format PEM? La chaîne au format PEM est une valeur d'en-tête "SSL_CLIENT_CERT" de la requête HTTP.

RÉPONSE : Sur la base de la réponse de mgaert, voici ce que j'ai écrit dans Scala :

val cert = factory.generateCertificate(
    new ByteArrayInputStream(
      Base64.decodeBase64(
        cert.stripPrefix("-----BEGIN CERTIFICATE-----").stripSuffix("-----END CERTIFICATE-----")
      )
    ).asInstanceOf[X509Certificate]
javasslx509certificate
31
Jeffrey Chung

Décodez le Base64 en binaire, avec quelques InputStream le lisant, puis essayez

CertificateFactory cf = CertificateFactory.getInstance("X.509");
Certificate cert = cf.generateCertificate(is);
42
mgaert

Les étapes de conversion d'une chaîne au format PEM sont opposées à la façon dont (x509 -> chaîne) s'est déroulé.

Exemple de chaîne formatée PEM:

-----BEGIN CERTIFICATE-----
MIIEczCCA1ugAwIBAgIBADANBgkqhkiG9w0BAQQFAD..AkGA1UEBhMCR0Ix
EzARBgNVBAgTClNvbWUtU3RhdGUxFDASBgNVBAoTC0..0EgTHRkMTcwNQYD
VQQLEy5DbGFzcyAxIFB1YmxpYyBQcmltYXJ5IENlcn..XRpb24gQXV0aG9y
aXR5MRQwEgYDVQQDEwtCZXN0IENBIEx0ZDAeFw0wMD..TUwMTZaFw0wMTAy
MDQxOTUwMTZaMIGHMQswCQYDVQQGEwJHQjETMBEGA1..29tZS1TdGF0ZTEU
MBIGA1UEChMLQmVzdCBDQSBMdGQxNzA1BgNVBAsTLk..DEgUHVibGljIFBy
aW1hcnkgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkxFD..AMTC0Jlc3QgQ0Eg
THRkMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCg..Tz2mr7SZiAMfQyu
vBjM9OiJjRazXBZ1BjP5CE/Wm/Rr500PRK+Lh9x5eJ../ANBE0sTK0ZsDGM
ak2m1g7oruI3dY3VHqIxFTz0Ta1d+NAjwnLe4nOb7/..k05ShhBrJGBKKxb
8n104o/5p8HAsZPdzbFMIyNjJzBM2o5y5A13wiLitE..fyYkQzaxCw0Awzl
kVHiIyCuaF4wj571pSzkv6sv+4IDMbT/XpCo8L6wTa..sh+etLD6FtTjYbb
rvZ8RQM1tlKdoMHg2qxraAV++HNBYmNWs0duEdjUbJ..XI9TtnS4o1Ckj7P
OfljiQIDAQABo4HnMIHkMB0GA1UdDgQWBBQ8urMCRL..5AkIp9NJHJw5TCB
tAYDVR0jBIGsMIGpgBQ8urMCRLYYMHUKU5AkIp9NJH..aSBijCBhzELMAkG
A1UEBhMCR0IxEzARBgNVBAgTClNvbWUtU3RhdGUxFD..AoTC0Jlc3QgQ0Eg
THRkMTcwNQYDVQQLEy5DbGFzcyAxIFB1YmxpYyBQcm..ENlcnRpZmljYXRp
b24gQXV0aG9yaXR5MRQwEgYDVQQDEwtCZXN0IENBIE..DAMBgNVHRMEBTAD
AQH/MA0GCSqGSIb3DQEBBAUAA4IBAQC1uYBcsSncwA..DCsQer772C2ucpX
xQUE/C0pWWm6gDkwd5D0DSMDJRqV/weoZ4wC6B73f5..bLhGYHaXJeSD6Kr
XcoOwLdSaGmJYslLKZB3ZIDEp0wYTGhgteb6JFiTtn..sf2xdrYfPCiIB7g
BMAV7Gzdc4VspS6ljrAhbiiawdBiQlQmsBeFz9JkF4..b3l8BoGN+qMa56Y
It8una2gY4l2O//on88r5IWJlm1L0oA8e4fR2yrBHX..adsGeFKkyNrwGi/
7vQMfXdGsRrXNGRGnX+vWDZ3/zWI0joDtCkNnqEpVn..HoX
-----END CERTIFICATE-----

Voici les étapes:

1. Remove headers from PEM formatted String
Headers are : ---- BEGIN CERTIFICATE ----- and ----- END CERTIFICATE ------
2. Decode the rest of the part using Base64 to byte array
3. Then you can use CertificateFactory to convert byte stream to x509Certificate object

Exemple de code à faire ci-dessus (avec PEM Writer):

  /**
     * Converts a PEM formatted String to a {@link X509Certificate} instance.
     *
     * @param pem PEM formatted String
     * @return a X509Certificate instance
     * @throws CertificateException 
     * @throws IOException
     */
    public X509Certificate convertToX509Certificate(String pem) throws CertificateException, IOException {
        X509Certificate cert = null;
        StringReader reader = new StringReader(pem);
        PEMReader pr = new PEMReader(reader);
        cert = (X509Certificate)pr.readObject();
        return cert;
    }
10
Balaji Boggaram Ramanarayan

Un autre échantillon,

public static X509Certificate convertToX509Cert(String certificateString) throws CertificateException {
    X509Certificate certificate = null;
    CertificateFactory cf = null;
    try {
        if (certificateString != null && !certificateString.trim().isEmpty()) {
            certificateString = certificateString.replace("-----BEGIN CERTIFICATE-----\n", "")
                    .replace("-----END CERTIFICATE-----", ""); // NEED FOR PEM FORMAT CERT STRING
            byte[] certificateData = Base64.getDecoder().decode(certificateString);
            cf = CertificateFactory.getInstance("X509");
            certificate = (X509Certificate) cf.generateCertificate(new ByteArrayInputStream(certificateData));
        }
    } catch (CertificateException e) {
        throw new CertificateException(e);
    }
    return certificate;
}
2
Zeigeist