diff options
| author | netconomy <netconomy@7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c> | 2007-08-17 06:10:56 +0000 |
|---|---|---|
| committer | netconomy <netconomy@7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c> | 2007-08-17 06:10:56 +0000 |
| commit | 3d982813b34f6f230baf4a467cdc37ec92a77595 (patch) | |
| tree | 85319d39cee2ded1bb7a2b2dd9e8ea37e3778248 /src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java | |
| parent | 07f6c8f33b2d700276fe6ec6339ff836c8710131 (diff) | |
| download | pdf-as-3-3d982813b34f6f230baf4a467cdc37ec92a77595.tar.gz pdf-as-3-3d982813b34f6f230baf4a467cdc37ec92a77595.tar.bz2 pdf-as-3-3d982813b34f6f230baf4a467cdc37ec92a77595.zip | |
Performance
git-svn-id: https://joinup.ec.europa.eu/svn/pdf-as/trunk@167 7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c
Diffstat (limited to 'src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java')
| -rw-r--r-- | src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java b/src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java new file mode 100644 index 0000000..19d7b33 --- /dev/null +++ b/src/main/java/at/gv/egiz/pdfas/utils/DataHashUtils.java @@ -0,0 +1,136 @@ +/**
+ *
+ */
+package at.gv.egiz.pdfas.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.security.DigestInputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import org.apache.commons.codec.binary.Base64;
+
+import at.knowcenter.wag.egov.egiz.pdf.BinarySignatureHolder;
+import at.knowcenter.wag.egov.egiz.pdf.SignatureHolder;
+import at.knowcenter.wag.egov.egiz.pdf.TextualSignatureHolder;
+
+/**
+ * Contains helpful methods for building data hashed.
+ *
+ * <p>
+ * Data hashes are useful for summarizing the signed data of signatures for
+ * debugging and testing purposes. Do not use these hashes for signatures.
+ * </p>
+ * <p>
+ * A data hash is always a Base64 encoded String.
+ * </p>
+ *
+ * @author wprinz
+ *
+ */
+public final class DataHashUtils
+{
+
+ /**
+ *
+ * @param text
+ * @return
+ */
+ public static String buildDataHash(String text)
+ {
+ try
+ {
+ MessageDigest md = getMessageDigest();
+ // probable performance leak for very large texts
+ md.update(text.getBytes("UTF-8"));
+ byte[] rawDigest = md.digest();
+
+ return encodeDigest(rawDigest);
+ }
+ catch (UnsupportedEncodingException e)
+ {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public static String buildDataHash(byte[] data)
+ {
+ MessageDigest md = getMessageDigest();
+ md.update(data);
+ byte[] rawDigest = md.digest();
+
+ return encodeDigest(rawDigest);
+ }
+
+ public static String buildDataHash(InputStream is)
+ {
+ try
+ {
+ MessageDigest md = getMessageDigest();
+
+ DigestInputStream dis = new DigestInputStream(is, md);
+
+ byte[] temp = new byte[1024];
+ int i = 0;
+ while (dis.read(temp) >= 0)
+ {
+ // this just keeps the compiler from optimizing this loop away
+ i++;
+ }
+ dis.close();
+
+ byte[] rawDigest = md.digest();
+
+ return encodeDigest(rawDigest);
+ }
+ catch (IOException e)
+ {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public static String buildDataHash(SignatureHolder sh)
+ {
+ if (sh instanceof TextualSignatureHolder)
+ {
+ TextualSignatureHolder tsh = (TextualSignatureHolder) sh;
+ String signedText = tsh.getSignedText();
+ return buildDataHash(signedText);
+ }
+
+ {
+ BinarySignatureHolder bsh = (BinarySignatureHolder) sh;
+ InputStream is = bsh.getSignedPdf().createInputStream();
+ return buildDataHash(is);
+ }
+ }
+
+ protected static MessageDigest getMessageDigest()
+ {
+ try
+ {
+ MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+ return sha1;
+ }
+ catch (NoSuchAlgorithmException e)
+ {
+ throw new RuntimeException(e);
+ }
+ }
+
+ protected static String encodeDigest(byte[] rawDigest)
+ {
+ try
+ {
+ byte[] encoded = Base64.encodeBase64(rawDigest);
+ String str = new String(encoded, "US-ASCII");
+ return str;
+ }
+ catch (UnsupportedEncodingException e)
+ {
+ throw new RuntimeException(e);
+ }
+ }
+}
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