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<TITLE>Listing All Available Cryptographic Services
(Java Developers Almanac Example)
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<META CONTENT="Patrick Chan" NAME="AUTHOR">
<META CONTENT="Code Examples from The Java Developers Almanac 1.4" NAME="DESCRIPTION">
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<B><A HREF="../java.security/pkg.html">java.security</A></B><font color="#666666" SIZE="-2">
[30 examples]
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<h3>
e194.
Listing All Available Cryptographic Services</h3>
The providers of cryptographic services such as key generation
algorithms, register their services with the <code>Security</code> class. A
service is represented by a name of the form:
<pre>
<font color="#0066ff"><i>service-type</i></font>.<font color="#0066ff"><i>service-implementation</i></font>
</pre>
An example of a service entry is <code>SecureRandom.SHA1PRNG</code>.
<pre>
// This method returns all available services types
public static String[] getServiceTypes() {
Set result = new HashSet();
// All all providers
Provider[] providers = Security.getProviders();
for (int i=0; i<providers.length; i++) {
// Get services provided by each provider
Set keys = providers[i].keySet();
for (Iterator it=keys.iterator(); it.hasNext(); ) {
String key = (String)it.next();
key = key.split(" ")[0];
if (key.startsWith("Alg.Alias.")) {
// Strip the alias
key = key.substring(10);
}
int ix = key.indexOf('.');
result.add(key.substring(0, ix));
}
}
return (String[])result.toArray(new String[result.size()]);
}
// This method returns the available implementations for a service type
public static String[] getCryptoImpls(String serviceType) {
Set result = new HashSet();
// All all providers
Provider[] providers = Security.getProviders();
for (int i=0; i<providers.length; i++) {
// Get services provided by each provider
Set keys = providers[i].keySet();
for (Iterator it=keys.iterator(); it.hasNext(); ) {
String key = (String)it.next();
key = key.split(" ")[0];
if (key.startsWith(serviceType+".")) {
result.add(key.substring(serviceType.length()+1));
} else if (key.startsWith("Alg.Alias."+serviceType+".")) {
// This is an alias
result.add(key.substring(serviceType.length()+11));
}
}
}
return (String[])result.toArray(new String[result.size()]);
}
</pre>
Here's a sample list of service types:
<pre>
AlgorithmParameterGenerator
AlgorithmParameters
CertPathBuilder
CertPathValidator
CertStore
CertificateFactory
Cipher
GssApiMechanism
KeyAgreement
KeyFactory
KeyGenerator
KeyManagerFactory
KeyPairGenerator
KeyStore
Mac
MessageDigest
SSLContext
SecretKeyFactory
SecureRandom
Signature
TrustManagerFactory
</pre>
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Related Examples
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e193. <a class="eglink" href="EnableDebug.html?l=rel">
Printing Security System Trace Messages
</a>
<br>
e195. <a class="eglink" href="ListSecureRnd.html?l=rel">
Listing All Available Secure Random Number Generators
</a>
<br>
e196. <a class="eglink" href="CreateSecureRandom.html?l=rel">
Generating a Secure Random Number
</a>
<br>
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See also:
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Key%20Store">
Key Store
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Message%20Digests">
Message Digests
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Permissions">
Permissions
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Policy%20Files">
Policy Files
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Public%20and%20Private%20Keys">
Public and Private Keys
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Signatures">
Signatures
</a>
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