CertUtil (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.i2p.crypto.CertUtil

```
public final class CertUtil
extends Object
```
Java X.509 certificate utilities, consolidated from various places.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`exportCert(Certificate cert, OutputStream out)` Modified from: http://www.exampledepot.com/egs/java.security.cert/ExportCert.html Writes a certificate in base64 format.
`static void`	`exportCRL(X509CRL crl, OutputStream out)` Writes a CRL in base64 format.
`static void`	`exportPrivateKey(PrivateKey pk, Certificate[] certs, OutputStream out)` Writes the private key and all certs in base64 format.
`static String`	`getIssuerValue(X509Certificate cert, String type)` Get a value out of the issuer distinguished name.
`static Set<String>`	`getSubjectAlternativeNames(X509Certificate cert)` Get the set of Subject Alternative Names, including DNSNames, RFC822Names, IPv4 and v6 addresses as strings.
`static String`	`getSubjectValue(X509Certificate cert, String type)` Get a value out of the subject distinguished name.
`static boolean`	`isRevoked(Certificate cert)` Is the certificate revoked? This loads the CRLs from disk.
`static boolean`	`isRevoked(CertStore store, Certificate cert)` Is the certificate revoked?
`static boolean`	`isRevoked(I2PAppContext ctx, Certificate cert)` Is the certificate revoked? This loads the CRLs from disk.
`static X509Certificate`	`loadCert(File kd)` Get the certificate from a X.509 certificate file.
`static List<X509Certificate>`	`loadCerts(InputStream in)` Get one or more certificates from an input stream.
`static X509CRL`	`loadCRL(InputStream in)` Load a CRL.
`static CertStore`	`loadCRLs()` Load CRLs from standard locations.
`static CertStore`	`loadCRLs(I2PAppContext ctx)` Load CRLs from standard locations.
`static PublicKey`	`loadKey(File kd)` Get the Java public key from a X.509 certificate file.
`static PrivateKey`	`loadPrivateKey(InputStream in)` Get a single Private Key from an input stream.
`static void`	`main(String[] args)` For testing purposes.
`static boolean`	`saveCert(Certificate cert, File file)` Write a certificate to a file in base64 format.
`static boolean`	`saveCRL(X509CRL crl, File file)` Write a CRL to a file in base64 format.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - exportCert
```
public static void exportCert(Certificate cert,
                              OutputStream out)
                       throws IOException,
                              CertificateEncodingException
```
    Modified from: http://www.exampledepot.com/egs/java.security.cert/ExportCert.html Writes a certificate in base64 format. Does NOT close the stream. Throws on all errors.
    Parameters:
    cert - the certificate to export
    out - the output stream to write to
    Throws:
    IOException - if the write fails
    CertificateEncodingException - if the certificate cannot be encoded
  - exportCRL
```
public static void exportCRL(X509CRL crl,
                             OutputStream out)
                      throws IOException,
                             CRLException
```
    Writes a CRL in base64 format. Does NOT close the stream. Throws on all errors.
    Parameters:
    crl - the CRL to export
    out - the output stream to write to
    Throws:
    IOException - if the write fails
    CRLException - if the crl does not support encoding
  - exportPrivateKey
```
public static void exportPrivateKey(PrivateKey pk,
                                    Certificate[] certs,
                                    OutputStream out)
                             throws IOException,
                                    GeneralSecurityException
```
    Writes the private key and all certs in base64 format. Does NOT close the stream. Throws on all errors.
    Parameters:
    pk - non-null
    certs - certificate chain, null or empty to export pk only
    out - the output stream to write to
    Throws:
    InvalidKeyException - if the key does not support encoding
    CertificateEncodingException - if a cert does not support encoding
    IOException - if the write fails
    GeneralSecurityException - on any other security error
  - getIssuerValue
```
public static String getIssuerValue(X509Certificate cert,
                                    String type)
```
    Get a value out of the issuer distinguished name. Warning - unsupported in Android (no javax.naming), returns null.
    Parameters:
    cert - the certificate
    type - e.g. "CN"
    Returns:
    the issuer value
  - getSubjectAlternativeNames
```
public static Set<String> getSubjectAlternativeNames(X509Certificate cert)
```
    Get the set of Subject Alternative Names, including DNSNames, RFC822Names, IPv4 and v6 addresses as strings. see X509Certificate.getSubjectAlternativeNames()
    Parameters:
    cert - the certificate to extract names from
    Returns:
    non-null, empty on error or none found
  - getSubjectValue
```
public static String getSubjectValue(X509Certificate cert,
                                     String type)
```
    Get a value out of the subject distinguished name. Warning - unsupported in Android (no javax.naming), returns null.
    Parameters:
    cert - the certificate
    type - e.g. "CN"
    Returns:
    the subject value
  - isRevoked
```
public static boolean isRevoked(Certificate cert)
```
    Is the certificate revoked? This loads the CRLs from disk. For efficiency, call loadCRLs() and then pass to isRevoked().
    Parameters:
    cert - the certificate to check
    Returns:
    true if revoked
  - isRevoked
```
public static boolean isRevoked(CertStore store,
                                Certificate cert)
```
    Is the certificate revoked?
    Parameters:
    store - the cert store containing CRLs
    cert - the certificate to check
    Returns:
    true if revoked
  - isRevoked
```
public static boolean isRevoked(I2PAppContext ctx,
                                Certificate cert)
```
    Is the certificate revoked? This loads the CRLs from disk. For efficiency, call loadCRLs() and then pass to isRevoked().
    Parameters:
    ctx - the context
    cert - the certificate to check
    Returns:
    true if revoked
  - loadCert
```
public static X509Certificate loadCert(File kd)
                                throws IOException,
                                       GeneralSecurityException
```
    Get the certificate from a X.509 certificate file. Throws if the certificate is invalid (e.g. expired). This does NOT check for revocation. This verifies the signature, assuming it is self-signed, but will not throw an exception, will log a warning only, as of 0.9.54. We do NOT fetch additional certs or attempt to validate a cert up the chain.
    Parameters:
    kd - the certificate file
    Returns:
    non-null, throws on all errors including certificate invalid
    Throws:
    IOException - if the file cannot be read
    GeneralSecurityException - if the certificate is invalid
  - loadCerts
```
public static List<X509Certificate> loadCerts(InputStream in)
                                       throws IOException,
                                              GeneralSecurityException
```
    Get one or more certificates from an input stream. Throws if any certificate is invalid (e.g. expired). Does NOT close the stream. This does NOT check for revocation.
    Parameters:
    in - the input stream to read from
    Returns:
    non-null, non-empty, throws on all errors including certificate invalid
    Throws:
    IOException - if the read fails
    GeneralSecurityException - if any certificate is invalid
  - loadCRL
```
public static X509CRL loadCRL(InputStream in)
                       throws GeneralSecurityException
```
    Load a CRL. Does NOT Close the stream.
    Parameters:
    in - the input stream to read from
    Returns:
    non-null
    Throws:
    GeneralSecurityException - if the CRL cannot be loaded
  - loadCRLs
```
public static CertStore loadCRLs()
```
    Load CRLs from standard locations.
    Returns:
    non-null, possibly empty
  - loadCRLs
```
public static CertStore loadCRLs(I2PAppContext ctx)
```
    Load CRLs from standard locations.
    Parameters:
    ctx - the application context
    Returns:
    non-null, possibly empty
  - loadKey
```
public static PublicKey loadKey(File kd)
                         throws IOException,
                                GeneralSecurityException
```
    Get the Java public key from a X.509 certificate file. Throws if the certificate is invalid (e.g. expired). This DOES check for revocation.
    Parameters:
    kd - the certificate file
    Returns:
    non-null, throws on all errors including certificate invalid
    Throws:
    IOException - if the file cannot be read
    GeneralSecurityException - if the certificate is invalid
  - loadPrivateKey
```
public static PrivateKey loadPrivateKey(InputStream in)
                                 throws IOException,
                                        GeneralSecurityException
```
    Get a single Private Key from an input stream. Does NOT close the stream.
    Parameters:
    in - the input stream to read from
    Returns:
    non-null, non-empty, throws on all errors including certificate invalid
    Throws:
    IOException - if the read fails
    GeneralSecurityException - if the key is invalid
  - main
```
public static final void main(String[] args)
```
    For testing purposes.
    Parameters:
    args - command-line arguments
  - saveCert
```
public static boolean saveCert(Certificate cert,
                               File file)
```
    Write a certificate to a file in base64 format.
    Parameters:
    cert - the certificate to save
    file - the file to write to
    Returns:
    success
  - saveCRL
```
public static boolean saveCRL(X509CRL crl,
                              File file)
```
    Write a CRL to a file in base64 format.
    Parameters:
    crl - the CRL to save
    file - the file to write to
    Returns:
    success

Class CertUtil

Method Summary

Methods inherited from class java.lang.Object

Method Detail

exportCert

exportCRL

exportPrivateKey

getIssuerValue

getSubjectAlternativeNames

getSubjectValue

isRevoked

isRevoked

isRevoked

loadCert

loadCerts

loadCRL

loadCRLs

loadCRLs

loadKey

loadPrivateKey

main

saveCert

saveCRL