Java by API/java.security/Security

Security: addProvider(Provider provider)

   <source lang="java">

import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException; import java.security.DigestInputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.Provider; import java.security.Security; import java.util.zip.CRC32; public class MainClass {

 static private String hexDigit(byte x) {
   StringBuffer sb = new StringBuffer();
   char c;
   // First nibble
   c = (char) ((x >> 4) & 0xf);
   if (c > 9) {
     c = (char) ((c - 10) + "a");
   } else {
     c = (char) (c + "0");
   }
   sb.append(c);
   // Second nibble
   c = (char) (x & 0xf);
   if (c > 9) {
     c = (char) ((c - 10) + "a");
   } else {
     c = (char) (c + "0");
   }
   sb.append(c);
   return sb.toString();
 }
 static private String computeDigest(MessageDigest algorithm, String filename) {
   String returnValue = "";
   try {
     algorithm.reset();
     FileInputStream fis = new FileInputStream(filename);
     BufferedInputStream bis = new BufferedInputStream(fis);
     DigestInputStream dis = new DigestInputStream(bis, algorithm);
     int ch;
     while ((ch = dis.read()) != -1)
       ;
     StringBuffer hexString = new StringBuffer();
     byte digest[] = algorithm.digest();
     int digestLength = digest.length;
     for (int i = 0; i < digestLength; i++) {
       hexString.append(hexDigit(digest[i]));
       hexString.append(" ");
     }
     returnValue = hexString.toString();
   } catch (IOException e) {
     System.err.println("Error generating digest for: " + filename);
   }
   return returnValue;
 }
 public static void main(String args[]) {
   MessageDigest algorithm = null;
   Security.addProvider(new MyProvider());
   try {
     algorithm = MessageDigest.getInstance("CRC32");
   } catch (NoSuchAlgorithmException e) {
     System.err.println("Invalid algorithm");
     System.exit(-1);
   }
   int argsLength = args.length;
   for (int i = 0; i < argsLength; i++) {
     String digest = computeDigest(algorithm, args[i]);
     System.out.println(args[i] + " : " + digest);
   }
 }

} class MyProvider extends Provider {

 public MyProvider() {
   super("MyProvider", 1.0, "jexp.ru Collections Example");
   put("CRC32", "CRC");
 }

} class CRC extends MessageDigest {

 CRC32 crc;
 public CRC() {
   super("CRC");
   crc = new CRC32();
 }
 protected void engineReset() {
   crc.reset();
 }
 protected void engineUpdate(byte input) {
   crc.update(input);
 }
 protected void engineUpdate(byte[] input, int offset, int len) {
   crc.update(input, offset, len);
 }
 protected byte[] engineDigest() {
   long l = crc.getValue();
   byte[] bytes = new byte[4];
   bytes[3] = (byte) ((l & 0xFF000000) >> 24);
   bytes[2] = (byte) ((l & 0x00FF0000) >> 16);
   bytes[1] = (byte) ((l & 0x0000FF00) >> 8);
   bytes[0] = (byte) ((l & 0x000000FF) >> 0);
   return bytes;
 }

}

      </source>
   
  
 
  

Security: getProviders()

   <source lang="java">

/* Ciphers:

           None available.

KeyAgreeents:

           None available.

Macs:

           None available.

MessageDigests:

           SHA-512
           SHA1
           MD2
           SHA
           SHA ImplementedIn
           SHA-256
           MD5 ImplementedIn
           SHA-1
           MD5
           SHA-384

Signatures:

           OID.1.2.840.10040.4.3
           OID.1.2.840.113549.1.1.4
           SHA384withRSA
           1.3.14.3.2.29
           SHA512withRSA SupportedKeyClasses
           SHA/DSA
           SHA1withDSA KeySize
           NONEwithDSA SupportedKeyClasses
           OID.1.2.840.113549.1.1.5
           SHA512withRSA
           MD5withRSA
           DSS
           OID.1.2.840.113549.1.1.11
           SHA384withRSA SupportedKeyClasses
           SHA1withRSA
           MD5withRSA SupportedKeyClasses
           NONEwithDSA
           1.2.840.113549.1.1.4
           MD5andSHA1withRSA
           1.2.840.113549.1.1.11
           OID.1.2.840.113549.1.1.13
           1.3.14.3.2.27
           1.2.840.10040.4.3
           SHA256withRSA
           MD2withRSA SupportedKeyClasses
           1.2.840.113549.1.1.2
           1.2.840.113549.1.1.12
           RawDSA
           SHA1withDSA
           SHA1/DSA
           MD2withRSA
           1.3.14.3.2.13
           SHAwithDSA
           DSAWithSHA1
           1.2.840.113549.1.1.13
           OID.1.3.14.3.2.29
           SHA1withDSA ImplementedIn
           SHA256withRSA SupportedKeyClasses
           SHA1withDSA SupportedKeyClasses
           DSA
           1.2.840.113549.1.1.5
           SHA-1/DSA
           SHA1withRSA SupportedKeyClasses
           OID.1.2.840.113549.1.1.12
           OID.1.2.840.113549.1.1.2
*/

import java.security.Provider; import java.security.Security; import java.util.HashSet; import java.util.Iterator; import java.util.Set; public class ListAlgorithms {

 public static void printSet(String setName, Set algorithms) {
   System.out.println(setName + ":");
   if (algorithms.isEmpty()) {
     System.out.println("            None available.");
   } else {
     Iterator it = algorithms.iterator();
     while (it.hasNext()) {
       String name = (String) it.next();
       System.out.println("            " + name);
     }
   }
 }
 public static void main(String[] args) {
   Provider[] providers = Security.getProviders();
   Set<String> ciphers = new HashSet<String>();
   Set<String> keyAgreements = new HashSet<String>();
   Set<String> macs = new HashSet<String>();
   Set<String> messageDigests = new HashSet<String>();
   Set<String> signatures = new HashSet<String>();
   for (int i = 0; i != providers.length; i++) {
     Iterator it = providers[i].keySet().iterator();
     while (it.hasNext()) {
       String entry = (String) it.next();
       if (entry.startsWith("Alg.Alias.")) {
         entry = entry.substring("Alg.Alias.".length());
       }
       if (entry.startsWith("Cipher.")) {
         ciphers.add(entry.substring("Cipher.".length()));
       } else if (entry.startsWith("KeyAgreement.")) {
         keyAgreements.add(entry.substring("KeyAgreement.".length()));
       } else if (entry.startsWith("Mac.")) {
         macs.add(entry.substring("Mac.".length()));
       } else if (entry.startsWith("MessageDigest.")) {
         messageDigests.add(entry.substring("MessageDigest.".length()));
       } else if (entry.startsWith("Signature.")) {
         signatures.add(entry.substring("Signature.".length()));
       }
     }
   }
   printSet("Ciphers", ciphers);
   printSet("KeyAgreeents", keyAgreements);
   printSet("Macs", macs);
   printSet("MessageDigests", messageDigests);
   printSet("Signatures", signatures);
 }

}

      </source>