Make cipher field in AESCipher and AESCipherCBCnoPad thread safe

DEVSIX-8435

Autoported commit.
Original commit hash: [cecbc2716]
Manual files:
kernel/src/main/java/com/itextpdf/kernel/crypto/AESCipher.java
kernel/src/main/java/com/itextpdf/kernel/crypto/AESCipherCBCnoPad.java
kernel/src/main/java/com/itextpdf/kernel/crypto/securityhandler/EncryptionUtils.java
sign/src/main/java/com/itextpdf/signatures/validation/v1/SignatureValidationProperties.java

itext/itext.kernel/itext/kernel/crypto/AESCipherCBCnoPad.cs

@@ -26,7 +26,7 @@ You should have received a copy of the GNU Affero General Public License
 namespace iText.Kernel.Crypto {
     /// <summary>Creates an AES Cipher with CBC and no padding.</summary>
     public class AESCipherCBCnoPad {
-        private static ICipherCBCnoPad cipher;
+        private ICipherCBCnoPad cipher;
 
         /// <summary>Creates a new instance of AESCipher with CBC and no padding</summary>
         /// <param name="forEncryption">

itext/itext.kernel/itext/kernel/pdf/PdfNumTree.cs

@@ -75,9 +75,9 @@ public virtual PdfDictionary BuildTree() {
             if (numbers.Length <= NODE_SIZE) {
                 PdfDictionary dic = new PdfDictionary();
                 PdfArray ar = new PdfArray();
-                for (int k = 0; k < numbers.Length; ++k) {
-                    ar.Add(new PdfNumber((int)numbers[k]));
-                    ar.Add(items.Get(numbers[k]));
+                foreach (int? number in numbers) {
+                    ar.Add(new PdfNumber((int)number));
+                    ar.Add(items.Get(number));
                 }
                 dic.Put(PdfName.Nums, ar);
                 return dic;

itext/itext.kernel/itext/kernel/pdf/PdfWriter.cs

@@ -94,7 +94,7 @@ public PdfWriter(String filename, WriterProperties properties)
         /// <summary>Indicates if to use full compression mode.</summary>
         /// <returns>true if to use full compression, false otherwise.</returns>
         public virtual bool IsFullCompression() {
-            return properties.isFullCompression != null ? (bool)properties.isFullCompression : false;
+            return properties.isFullCompression != null && (bool)properties.isFullCompression;
         }
 
         /// <summary>Gets default compression level for @see PdfStream.</summary>

itext/itext.sign/itext/signatures/validation/v1/SafeCalling.cs

@@ -48,8 +48,8 @@ public static void OnExceptionLog(Action action, ValidationReport report, Func<E
         /// <param name="defaultValue">The value to return when an exception is thrown</param>
         /// <param name="report">The report to add the ReportItem to</param>
         /// <param name="reportItemCreator">A callback to generate a ReportItem</param>
-        /// <returns>The returned value from the action</returns>
         /// <typeparam name="T"/>
+        /// <returns>The returned value from the action</returns>
         public static T OnExceptionLog<T>(Func<T> action, T defaultValue, ValidationReport report, Func<Exception, 
             ReportItem> reportItemCreator) {
             try {
@@ -80,8 +80,8 @@ public static void OnRuntimeExceptionLog(Action action, ValidationReport report,
         /// <param name="defaultValue">The value to return when an exception is thrown</param>
         /// <param name="report">The report to add the ReportItem to</param>
         /// <param name="reportItemCreator">A callback to generate a ReportItem</param>
-        /// <returns>The returned value from the action</returns>
         /// <typeparam name="T"/>
+        /// <returns>The returned value from the action</returns>
         public static T OnRuntimeExceptionLog<T>(Func<T> action, T defaultValue, ValidationReport report, Func<Exception
             , ReportItem> reportItemCreator) {
             try {

port-hash

@@ -1 +1 @@
-5a8f86d5e1ee424e95f9bae23d0ae30f8a971989
+cecbc27166eb8d323051127a3436131ba4993639