java.security

Class KeyStore

java.lang.Object

java.security.KeyStore

public class KeyStore
extends Object

This class represents a storage facility for cryptographic keys and certificates.

A KeyStore manages different types of entries. Each type of entry implements the KeyStore.Entry interface. Three basic KeyStore.Entry implementations are provided:

• KeyStore.PrivateKeyEntry

  This type of entry holds a cryptographic PrivateKey, which is optionally stored in a protected format to prevent unauthorized access. It is also accompanied by a certificate chain for the corresponding public key.

  Private keys and certificate chains are used by a given entity for self-authentication. Applications for this authentication include software distribution organizations which sign JAR files as part of releasing and/or licensing software.

• KeyStore.SecretKeyEntry

  This type of entry holds a cryptographic SecretKey, which is optionally stored in a protected format to prevent unauthorized access.

• KeyStore.TrustedCertificateEntry

  This type of entry contains a single public key Certificate belonging to another party. It is called a trusted certificate because the keystore owner trusts that the public key in the certificate indeed belongs to the identity identified by the subject (owner) of the certificate.

  This type of entry can be used to authenticate other parties.

Each entry in a keystore is identified by an "alias" string. In the case of private keys and their associated certificate chains, these strings distinguish among the different ways in which the entity may authenticate itself. For example, the entity may authenticate itself using different certificate authorities, or using different public key algorithms.

Whether aliases are case sensitive is implementation dependent. In order to avoid problems, it is recommended not to use aliases in a KeyStore that only differ in case.

Whether keystores are persistent, and the mechanisms used by the keystore if it is persistent, are not specified here. This allows use of a variety of techniques for protecting sensitive (e.g., private or secret) keys. Smart cards or other integrated cryptographic engines (SafeKeyper) are one option, and simpler mechanisms such as files may also be used (in a variety of formats).

Typical ways to request a KeyStore object include relying on the default type and providing a specific keystore type.

• To rely on the default type:

   KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
   

  The system will return a keystore implementation for the default type.
• To provide a specific keystore type:

   KeyStore ks = KeyStore.getInstance("JKS");
   

  The system will return the most preferred implementation of the specified keystore type available in the environment.

Before a keystore can be accessed, it must be loaded.

 KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());

 // get user password and file input stream
 char[] password = getPassword();

 try (FileInputStream fis = new FileInputStream("keyStoreName")) {
        ks.load(fis, password);
 }
 

To create an empty keystore using the above load method, pass null as the InputStream argument.

Once the keystore has been loaded, it is possible to read existing entries from the keystore, or to write new entries into the keystore:

 KeyStore.ProtectionParameter protParam = new KeyStore.PasswordProtection(password);

 // get my private key
 KeyStore.PrivateKeyEntry pkEntry = (KeyStore.PrivateKeyEntry) ks.getEntry("privateKeyAlias", protParam);
 PrivateKey myPrivateKey = pkEntry.getPrivateKey();

 // save my secret key
 javax.crypto.SecretKey mySecretKey;
 KeyStore.SecretKeyEntry skEntry = new KeyStore.SecretKeyEntry(mySecretKey);
 ks.setEntry("secretKeyAlias", skEntry, protParam);

 // store away the keystore
 try (FileOutputStream fos = new FileOutputStream("newKeyStoreName")) {
        ks.store(fos, password);
 }
 

Note that although the same password may be used to load the keystore, to protect the private key entry, to protect the secret key entry, and to store the keystore (as is shown in the sample code above), different passwords or other protection parameters may also be used.

Every implementation of the Java platform is required to support the following standard KeyStore type:

• PKCS12

This type is described in the KeyStore section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other types are supported.

Since:

1.2

Author:

Jan Luehe

See Also:

Certificate

Constructor Summary

Constructors

Constructor and Description
KeyStore()

Method Summary

Modifier and Type	Method and Description
Enumeration<String>	aliases() Lists all the alias names of this keystore.
boolean	containsAlias(String alias) Checks if the given alias exists in this keystore.
void	deleteEntry(String alias) Deletes the entry identified by the given alias from this keystore.
Certificate	getCertificate(String alias) Returns the certificate associated with the given alias.
Certificate[]	getCertificateChain(String alias) Returns the certificate chain associated with the given alias.
static String	getDefaultType() Returns the default keystore type as specified by the keystore.type security property, or the string "jks" (acronym for "Java keystore") if no such property exists.
static KeyStore	getInstance(String type) Returns a keystore object of the specified type.
Key	getKey(String alias, char[] password) Returns the key associated with the given alias, using the given password to recover it.
String	getType() Returns the type of this keystore.
boolean	isCertificateEntry(String alias) Returns true if the entry identified by the given alias was created by a call to setCertificateEntry, or created by a call to setEntry with a TrustedCertificateEntry.
boolean	isKeyEntry(String alias) Returns true if the entry identified by the given alias was created by a call to setKeyEntry, or created by a call to setEntry with a PrivateKeyEntry or a SecretKeyEntry.
void	load(InputStream stream, char[] password) Loads this KeyStore from the given input stream.
void	setCertificateEntry(String alias, Certificate cert) Assigns the given trusted certificate to the given alias.
void	setKeyEntry(String alias, byte[] key, Certificate[] chain) Assigns the given key (that has already been protected) to the given alias.
int	size() Retrieves the number of entries in this keystore.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KeyStore

public KeyStore()

Method Detail

getInstance

public static KeyStore getInstance(String type)
                            throws KeyStoreException

Returns a keystore object of the specified type.

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new KeyStore object encapsulating the KeyStoreSpi implementation from the first Provider that supports the specified type is returned.

Parameters:

type - the type of keystore. See the KeyStore section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard keystore types.

Returns:

a keystore object of the specified type.

Throws:

KeyStoreException - if no Provider supports a KeyStoreSpi implementation for the specified type.

getDefaultType

public static final String getDefaultType()

Returns the default keystore type as specified by the keystore.type security property, or the string "jks" (acronym for "Java keystore") if no such property exists.

The default keystore type can be used by applications that do not want to use a hard-coded keystore type when calling one of the getInstance methods, and want to provide a default keystore type in case a user does not specify its own.

The default keystore type can be changed by setting the value of the keystore.type security property to the desired keystore type.

Returns:

the default keystore type as specified by the keystore.type security property, or the string "jks" if no such property exists.

getType

public final String getType()

Returns the type of this keystore.

Returns:

the type of this keystore.

getKey

@Nullable
public final Key getKey(String alias,
                                   char[] password)
                            throws KeyStoreException,
                                   NoSuchAlgorithmException,
                                   UnrecoverableKeyException

Returns the key associated with the given alias, using the given password to recover it. The key must have been associated with the alias by a call to setKeyEntry, or by a call to setEntry with a PrivateKeyEntry or SecretKeyEntry.

Parameters:

alias - the alias name

password - the password for recovering the key

Returns:

the requested key, or null if the given alias does not exist or does not identify a key-related entry.

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

NoSuchAlgorithmException - if the algorithm for recovering the key cannot be found

UnrecoverableKeyException - if the key cannot be recovered (e.g., the given password is wrong).

getCertificateChain

@Nullable
public final Certificate[] getCertificateChain(String alias)
                                                   throws KeyStoreException

Returns the certificate chain associated with the given alias. The certificate chain must have been associated with the alias by a call to setKeyEntry, or by a call to setEntry with a PrivateKeyEntry.

Parameters:

alias - the alias name

Returns:

the certificate chain (ordered with the user's certificate first followed by zero or more certificate authorities), or null if the given alias does not exist or does not contain a certificate chain

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

getCertificate

@Nullable
public final Certificate getCertificate(String alias)
                                            throws KeyStoreException

Returns the certificate associated with the given alias.

If the given alias name identifies an entry created by a call to setCertificateEntry, or created by a call to setEntry with a TrustedCertificateEntry, then the trusted certificate contained in that entry is returned.

If the given alias name identifies an entry created by a call to setKeyEntry, or created by a call to setEntry with a PrivateKeyEntry, then the first element of the certificate chain in that entry is returned.

Parameters:

alias - the alias name

Returns:

the certificate, or null if the given alias does not exist or does not contain a certificate.

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

setKeyEntry

public final void setKeyEntry(String alias,
                              byte[] key,
                              Certificate[] chain)
                       throws KeyStoreException

Assigns the given key (that has already been protected) to the given alias.

If the protected key is of type java.security.PrivateKey, it must be accompanied by a certificate chain certifying the corresponding public key. If the underlying keystore implementation is of type jks, key must be encoded as an EncryptedPrivateKeyInfo as defined in the PKCS #8 standard.

If the given alias already exists, the keystore information associated with it is overridden by the given key (and possibly certificate chain).

Parameters:

alias - the alias name

key - the key (in protected format) to be associated with the alias

chain - the certificate chain for the corresponding public key (only useful if the protected key is of type java.security.PrivateKey).

Throws:

KeyStoreException - if the keystore has not been initialized (loaded), or if this operation fails for some other reason.

setCertificateEntry

public final void setCertificateEntry(String alias,
                                      Certificate cert)
                               throws KeyStoreException

Assigns the given trusted certificate to the given alias.

If the given alias identifies an existing entry created by a call to setCertificateEntry, or created by a call to setEntry with a TrustedCertificateEntry, the trusted certificate in the existing entry is overridden by the given certificate.

Parameters:

alias - the alias name

cert - the certificate

Throws:

KeyStoreException - if the keystore has not been initialized, or the given alias already exists and does not identify an entry containing a trusted certificate, or this operation fails for some other reason.

deleteEntry

public final void deleteEntry(String alias)
                       throws KeyStoreException

Deletes the entry identified by the given alias from this keystore.

Parameters:

alias - the alias name

Throws:

KeyStoreException - if the keystore has not been initialized, or if the entry cannot be removed.

aliases

public final Enumeration<String> aliases()
                                  throws KeyStoreException

Lists all the alias names of this keystore.

Returns:

enumeration of the alias names

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

containsAlias

public final boolean containsAlias(String alias)
                            throws KeyStoreException

Checks if the given alias exists in this keystore.

Parameters:

alias - the alias name

Returns:

true if the alias exists, false otherwise

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

size

public final int size()
               throws KeyStoreException

Retrieves the number of entries in this keystore.

Returns:

the number of entries in this keystore

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

isKeyEntry

public final boolean isKeyEntry(String alias)
                         throws KeyStoreException

Returns true if the entry identified by the given alias was created by a call to setKeyEntry, or created by a call to setEntry with a PrivateKeyEntry or a SecretKeyEntry.

Parameters:

alias - the alias for the keystore entry to be checked

Returns:

true if the entry identified by the given alias is a key-related entry, false otherwise.

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

isCertificateEntry

public final boolean isCertificateEntry(String alias)
                                 throws KeyStoreException

Returns true if the entry identified by the given alias was created by a call to setCertificateEntry, or created by a call to setEntry with a TrustedCertificateEntry.

Parameters:

alias - the alias for the keystore entry to be checked

Returns:

true if the entry identified by the given alias contains a trusted certificate, false otherwise.

Throws:

KeyStoreException - if the keystore has not been initialized (loaded).

load

public final void load(@Nullable
                       InputStream stream,
                       @Nullable
                       char[] password)
                throws IOException,
                       NoSuchAlgorithmException,
                       CertificateException

Loads this KeyStore from the given input stream.

A password may be given to unlock the keystore (e.g. the keystore resides on a hardware token device), or to check the integrity of the keystore data. If a password is not given for integrity checking, then integrity checking is not performed.

In order to create an empty keystore, or if the keystore cannot be initialized from a stream, pass null as the stream argument.

Note that if this keystore has already been loaded, it is reinitialized and loaded again from the given input stream.

Parameters:

stream - the input stream from which the keystore is loaded, or null

password - the password used to check the integrity of the keystore, the password used to unlock the keystore, or null

Throws:

IOException - if there is an I/O or format problem with the keystore data, if a password is required but not given, or if the given password was incorrect. If the error is due to a wrong password, the cause of the IOException should be an UnrecoverableKeyException

NoSuchAlgorithmException - if the algorithm used to check the integrity of the keystore cannot be found

CertificateException - if any of the certificates in the keystore could not be loaded