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* accompanied this code).
*
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package sun.security.util;
import java.util.HashSet;
import java.util.Set;
import java.util.Arrays;
import java.util.Collection;
import java.util.regex.Pattern;
The class decomposes standard algorithms into sub-elements.
/**
* The class decomposes standard algorithms into sub-elements.
*/
public class AlgorithmDecomposer {
private static final Pattern transPattern = Pattern.compile("/");
private static final Pattern pattern =
Pattern.compile("with|and", Pattern.CASE_INSENSITIVE);
private static Set<String> decomposeImpl(String algorithm) {
// algorithm/mode/padding
String[] transTockens = transPattern.split(algorithm);
Set<String> elements = new HashSet<>();
for (String transTocken : transTockens) {
if (transTocken == null || transTocken.length() == 0) {
continue;
}
// PBEWith<digest>And<encryption>
// PBEWith<prf>And<encryption>
// OAEPWith<digest>And<mgf>Padding
// <digest>with<encryption>
// <digest>with<encryption>and<mgf>
String[] tokens = pattern.split(transTocken);
for (String token : tokens) {
if (token == null || token.length() == 0) {
continue;
}
elements.add(token);
}
}
return elements;
}
Decompose the standard algorithm name into sub-elements.
For example, we need to decompose "SHA1WithRSA" into "SHA1" and "RSA"
so that we can check the "SHA1" and "RSA" algorithm constraints
separately.
Please override the method if need to support more name pattern.
/**
* Decompose the standard algorithm name into sub-elements.
* <p>
* For example, we need to decompose "SHA1WithRSA" into "SHA1" and "RSA"
* so that we can check the "SHA1" and "RSA" algorithm constraints
* separately.
* <p>
* Please override the method if need to support more name pattern.
*/
public Set<String> decompose(String algorithm) {
if (algorithm == null || algorithm.length() == 0) {
return new HashSet<>();
}
Set<String> elements = decomposeImpl(algorithm);
// In Java standard algorithm name specification, for different
// purpose, the SHA-1 and SHA-2 algorithm names are different. For
// example, for MessageDigest, the standard name is "SHA-256", while
// for Signature, the digest algorithm component is "SHA256" for
// signature algorithm "SHA256withRSA". So we need to check both
// "SHA-256" and "SHA256" to make the right constraint checking.
// handle special name: SHA-1 and SHA1
if (elements.contains("SHA1") && !elements.contains("SHA-1")) {
elements.add("SHA-1");
}
if (elements.contains("SHA-1") && !elements.contains("SHA1")) {
elements.add("SHA1");
}
// handle special name: SHA-224 and SHA224
if (elements.contains("SHA224") && !elements.contains("SHA-224")) {
elements.add("SHA-224");
}
if (elements.contains("SHA-224") && !elements.contains("SHA224")) {
elements.add("SHA224");
}
// handle special name: SHA-256 and SHA256
if (elements.contains("SHA256") && !elements.contains("SHA-256")) {
elements.add("SHA-256");
}
if (elements.contains("SHA-256") && !elements.contains("SHA256")) {
elements.add("SHA256");
}
// handle special name: SHA-384 and SHA384
if (elements.contains("SHA384") && !elements.contains("SHA-384")) {
elements.add("SHA-384");
}
if (elements.contains("SHA-384") && !elements.contains("SHA384")) {
elements.add("SHA384");
}
// handle special name: SHA-512 and SHA512
if (elements.contains("SHA512") && !elements.contains("SHA-512")) {
elements.add("SHA-512");
}
if (elements.contains("SHA-512") && !elements.contains("SHA512")) {
elements.add("SHA512");
}
return elements;
}
Get aliases of the specified algorithm.
May support more algorithms in the future.
/**
* Get aliases of the specified algorithm.
*
* May support more algorithms in the future.
*/
public static Collection<String> getAliases(String algorithm) {
String[] aliases;
if (algorithm.equalsIgnoreCase("DH") ||
algorithm.equalsIgnoreCase("DiffieHellman")) {
aliases = new String[] {"DH", "DiffieHellman"};
} else {
aliases = new String[] {algorithm};
}
return Arrays.asList(aliases);
}
private static void hasLoop(Set<String> elements, String find, String replace) {
if (elements.contains(find)) {
if (!elements.contains(replace)) {
elements.add(replace);
}
elements.remove(find);
}
}
/*
* This decomposes a standard name into sub-elements with a consistent
* message digest algorithm name to avoid overly complicated checking.
*/
public static Set<String> decomposeOneHash(String algorithm) {
if (algorithm == null || algorithm.length() == 0) {
return new HashSet<>();
}
Set<String> elements = decomposeImpl(algorithm);
hasLoop(elements, "SHA-1", "SHA1");
hasLoop(elements, "SHA-224", "SHA224");
hasLoop(elements, "SHA-256", "SHA256");
hasLoop(elements, "SHA-384", "SHA384");
hasLoop(elements, "SHA-512", "SHA512");
return elements;
}
/*
* The provided message digest algorithm name will return a consistent
* naming scheme.
*/
public static String hashName(String algorithm) {
return algorithm.replace("-", "");
}
}