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Class sun.security.x509.X509Cert

java.lang.Object
   |
   +----sun.security.x509.X509Cert

public class X509Cert

extends Object

implements Certificate, Serializable

These certificates are managed and vouched for by Certificate Authorities (CAs). CAs are services which create certificates by placing data in the X.509 standard format and then digitally signing that data. Such signatures are quite difficult to forge. CAs act as trusted third parties, making introductions between agents who have no direct knowledge of each other. CA certificates are either signed by themselves, or by some other CA such as a "root" CA.

X.509 certificates have several mandatory data elements, including:

• The Subject Name, an X.500 Distinguished Name for the entity (subject) for which the certificate was issued.
• The Subject Public Key, the public key of the subject. This is one of the most important parts of the certificate.
• The Validity Period, a time period (e.g. six months) within which the certificate is valid (unless revoked).
• The Issuer Name, an X.500 Distinguished Name for the Certificate Authority (CA) which issued the certificate.
• A Serial Number assigned by the CA, for use in certificate revocation and other applications.

Note that at this time X.509 extension attributes are not yet supported. That is, generated certificates are X.509v1 format, and X.509v2/v3 extensions in imported certificates are ignored.

See Also:

CertAndKeyGen

algid

X509Cert()

Construct a uninitialized X509 Cert on which decode must later be called (or which may be deserialized).

X509Cert(byte[])

Unmarshals a certificate from its encoded form, parsing the encoded bytes.

X509Cert(byte[], int, int)

Unmarshals a certificate from its encoded form, parsing the encoded bytes.

X509Cert(DerValue)

Unmarshal a certificate from its encoded form, parsing a DER value.

X509Cert(X500Name, X509Key, Date, Date)

Partially constructs a certificate from descriptive parameters.

decode(InputStream)

Decode an X.509 certificate from an input stream.

encode(OutputStream)

Appends the certificate to an output stream.

encodeAndSign(BigInt, X500Signer)

Creates an X.509 certificate, and signs it using the issuer passed (associating a signature algorithm and an X.500 name).

equals(Object)

Compares two certificates.

equals(X509Cert)

Compares two certificates, returning false if any data differs between the two.

getFormat()

Returns the "X.509" format identifier.

getGuarantor()

Returns getIssuerName

getIssuerAlgorithmId()

Returns the algorithm used by the issuer to sign the certificate.

getIssuerName()

Returns the certificate issuer's X.500 distinguished name.

getNotAfter()

Returns the last time the certificate is valid.

getNotBefore()

Returns the first time the certificate is valid.

getPrincipal()

Returns getSubjectName

getPublicKey()

Returns the subject's public key.

getSerialNumber()

Returns the certificate's serial number.

getSignedCert()

Return the signed X.509 certificate as a byte array.

getSigner(AlgorithmId, PrivateKey)

Returns an X500Signer that may be used to create signatures.

getSubjectName()

Returns the subject's X.500 distinguished name.

getVerifier(String)

Returns a signature object that may be used to verify signatures created using a specified signature algorithm and the public key contained in this certificate.

getVersion()

Returns the X.509 version number of this certificate, zero based.

hashCode()

Calculates a hash code value for the object.

toString()

Returns a printable representation of the certificate.

toString(boolean)

Returns a printable representation of the certificate.

verify(PublicKey)

Throws an exception if the certificate is invalid because it is now outside of the certificate's validity period, or because it was not signed using the verification key provided.

 protected AlgorithmId algid

 public X509Cert()

Construct a uninitialized X509 Cert on which decode must later be called (or which may be deserialized).

 public X509Cert(byte cert[]) throws IOException

Unmarshals a certificate from its encoded form, parsing the encoded bytes. This form of constructor is used by agents which need to examine and use certificate contents. That is, this is one of the more commonly used constructors. Note that the buffer must include only a certificate, and no "garbage" may be left at the end. If you need to ignore data at the end of a certificate, use another constructor.

Parameters:

cert - the encoded bytes, with no terminatu (CONSUMED)

Throws: IOException

when the certificate is improperly encoded.

 public X509Cert(byte buf[],
                 int offset,
                 int len) throws IOException

Unmarshals a certificate from its encoded form, parsing the encoded bytes. This form of constructor is used by agents which need to examine and use certificate contents. That is, this is one of the most commonly used constructors.

Parameters:

buf - the buffer holding the encoded bytes

offset - the offset in the buffer where the bytes begin

len - how many bytes of certificate exist

Throws: IOException

when the certificate is improperly encoded.

 public X509Cert(DerValue derVal) throws IOException

Unmarshal a certificate from its encoded form, parsing a DER value. This form of constructor is used by agents which need to examine and use certificate contents.

Parameters:

derVal - the der value containing the encoded cert.

Throws: IOException

when the certificate is improperly encoded.

 public X509Cert(X500Name subjectName,
                 X509Key subjectPublicKey,
                 Date notBefore,
                 Date notAfter) throws CertException

Partially constructs a certificate from descriptive parameters. This constructor may be used by Certificate Authority (CA) code, which later signs and encodes the certificate. Also, self-signed certificates serve as CA certificates, and are sometimes used as certificate requests.

Until the certificate has been signed and encoded, some of the mandatory fields in the certificate will not be available via accessor functions: the serial number, issuer name and signing algorithm, and of course the signed certificate. The fields passed to this constructor are available, and must be non-null.

Note that the public key being signed is generally independent of the signature algorithm being used. So for example Diffie-Hellman keys (which do not support signatures) can be placed in X.509 certificates when some other signature algorithm (e.g. DSS/DSA, or one of the RSA based algorithms) is used.

Parameters:

subjectName - the X.500 distinguished name being certified

subjectPublicKey - the public key being certified. This must be an "X509Key" implementing the "PublicKey" interface.

notBefore - the first time the certificate is valid

notAfter - the last time the certificate is valid

Throws: CertException

if the public key is inappropriate

See Also:

CertAndKeyGen

 public void decode(InputStream in) throws IOException

Decode an X.509 certificate from an input stream.

Parameters:

in - an input stream holding at least one certificate

Throws: IOException

when the certificate is improperly encoded.

 public void encode(OutputStream out) throws IOException

Appends the certificate to an output stream.

Parameters:

out - an input stream to which the certificate is appended.

Throws: IOException

when appending fails.

 public boolean equals(Object other)

Compares two certificates. This is false if the certificates are not both X.509 certs, otherwise it compares them as binary data.

Parameters:

other - the object being compared with this one

Returns:

true iff the certificates are equivalent

Overrides:

equals in class Object

 public boolean equals(X509Cert src)

Compares two certificates, returning false if any data differs between the two.

Parameters:

other - the object being compared with this one

Returns:

true iff the certificates are equivalent

 public String getFormat()

Returns the "X.509" format identifier.

 public Principal getGuarantor()

Returns getIssuerName

 public Principal getPrincipal()

Returns getSubjectName

 public void verify(PublicKey issuerPublicKey) throws CertException

Throws an exception if the certificate is invalid because it is now outside of the certificate's validity period, or because it was not signed using the verification key provided. Successfully verifying a certificate does not indicate that one should trust the entity which it represents.

Note that since this class represents only a single X.509 certificate, it cannot know anything about the certificate chain which is used to provide the verification key and to establish trust. Other code must manage and use those cert chains.

For now, you must walk the cert chain being used to verify any given cert. Start at the root, which is a self-signed certificate; verify it using the key inside the certificate. Then use that to verify the next certificate in the chain, issued by that CA. In this manner, verify each certificate until you reach the particular certificate you wish to verify. You should not use a certificate if any of the verification operations for its certificate chain were unsuccessful.

Parameters:

issuerPublicKey - the public key of the issuing CA

Throws: CertException

when the certificate is not valid.

 public byte[] encodeAndSign(BigInt serial,
                             X500Signer issuer) throws IOException, SignatureException

Creates an X.509 certificate, and signs it using the issuer passed (associating a signature algorithm and an X.500 name). This operation is used to implement the certificate generation functionality of a certificate authority.

Parameters:

serial - the serial number of the certificate (non-null)

issuer - the certificate issuer (CA) (non-null)

Returns:

the signed certificate, as returned by getSignedCert

Throws: IOException

if any of the data could not be encoded, or when any mandatory data was omitted

Throws: SignatureException

on signing failures

See Also:

getSignedCert, getSigner, CertAndKeyGen

 public X500Signer getSigner(AlgorithmId algorithmId,
                             PrivateKey privateKey) throws NoSuchAlgorithmException, InvalidKeyException

Returns an X500Signer that may be used to create signatures. Those signature may in turn be verified using this certificate (or a copy of it).

NOTE: If the private key is by itself capable of creating signatures, this fact may not be recognized at this time. Specifically, the case of DSS/DSA keys which get their algorithm parameters from higher in the certificate chain is not supportable without using an X509CertChain API, and there is no current support for other sources of algorithm parameters.

Parameters:

algorithm - the signature algorithm to be used. Note that a given public/private key pair may support several such algorithms.

privateKey - the private key used to create the signature, which must correspond to the public key in this certificate

Returns:

the Signer object

Throws: NoSuchAlgorithmException

if the signature algorithm is not supported

Throws: InvalidKeyException

if either the key in the certificate, or the private key parameter, does not support the requested signature algorithm

 public Signature getVerifier(String algorithm) throws NoSuchAlgorithmException, InvalidKeyException

Returns a signature object that may be used to verify signatures created using a specified signature algorithm and the public key contained in this certificate.

NOTE: If the public key in this certificate is not by itself capable of verifying signatures, this may not be recognized at this time. Specifically, the case of DSS/DSA keys which get their algorithm parameters from higher in the certificate chain is not supportable without using an X509CertChain API, and there is no current support for other sources of algorithm parameters.

Parameters:

algorithm - the algorithm of the signature to be verified

Returns:

the Signature object

Throws: NoSuchAlgorithmException

if the signature algorithm is not supported

Throws: InvalidKeyException

if the key in the certificate does not support the requested signature algorithm

 public byte[] getSignedCert()

Return the signed X.509 certificate as a byte array. The bytes are in standard DER marshaled form. Null is returned in the case of a partially constructed cert.

 public BigInt getSerialNumber()

Returns the certificate's serial number. Null is returned in the case of a partially constructed cert.

 public X500Name getSubjectName()

Returns the subject's X.500 distinguished name.

 public X500Name getIssuerName()

Returns the certificate issuer's X.500 distinguished name. Null is returned in the case of a partially constructed cert.

 public AlgorithmId getIssuerAlgorithmId()

Returns the algorithm used by the issuer to sign the certificate. Null is returned in the case of a partially constructed cert.

 public Date getNotBefore()

Returns the first time the certificate is valid.

 public Date getNotAfter()

Returns the last time the certificate is valid.

 public PublicKey getPublicKey()

Returns the subject's public key. Note that some public key algorithms support an optional certificate generation policy where the keys in the certificates are not in themselves sufficient to perform a public key operation. Those keys need to be augmented by algorithm parameters, which the certificate generation policy chose not to place in the certificate.

Two such public key algorithms are: DSS/DSA, where algorithm parameters could be acquired from a CA certificate in the chain of issuers; and Diffie-Hellman, with a similar solution although the CA then needs both a Diffie-Hellman certificate and a signature capable certificate.

 public int getVersion()

Returns the X.509 version number of this certificate, zero based. That is, "2" indicates an X.509 version 3 (1993) certificate, and "0" indicates X.509v1 (1988). Zero is returned in the case of a partially constructed cert.

 public int hashCode()

Calculates a hash code value for the object. Objects which are equal will also have the same hashcode.

Overrides:

hashCode in class Object

 public String toString()

Returns a printable representation of the certificate. This does not contain all the information available to distinguish this from any other certificate. The certificate must be fully constructed before this function may be called; in particular, if you are creating certificates you must call encodeAndSign() before calling this function.

Overrides:

toString in class Object

 public String toString(boolean detailed)

Returns a printable representation of the certificate.

Parameters:

detailed - true iff lots of detail is requested

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