diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
index b668aab..71558ed 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
@@ -42,7 +42,7 @@
 
     // Reads node information from dictionary buffer and updates members with the information.
     AK_FORCE_INLINE void fetchNodeInfoFromBuffer(const int nodePos) {
-        fetchNodeInfoFromBufferAndGetNodeCodePoints(mNodePos , 0 /* maxCodePointCount */,
+        fetchNodeInfoFromBufferAndGetNodeCodePoints(nodePos , 0 /* maxCodePointCount */,
                 0 /* outCodePoints */);
     }
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
index 9a180e6..0b73efa 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.cpp
@@ -27,6 +27,8 @@
 namespace latinime {
 
 const DynamicPatriciaTriePolicy DynamicPatriciaTriePolicy::sInstance;
+// To avoid infinite loop caused by invalid or malicious forward links.
+const int DynamicPatriciaTriePolicy::MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP = 100000;
 
 void DynamicPatriciaTriePolicy::createAndGetAllChildNodes(const DicNode *const dicNode,
         const BinaryDictionaryInfo *const binaryDictionaryInfo,
@@ -37,14 +39,23 @@
     DynamicPatriciaTrieNodeReader nodeReader(binaryDictionaryInfo);
     int mergedNodeCodePoints[MAX_WORD_LENGTH];
     int nextPos = dicNode->getChildrenPos();
+    int totalChildCount = 0;
     do {
         const int childCount = PatriciaTrieReadingUtils::getGroupCountAndAdvancePosition(
                 binaryDictionaryInfo->getDictRoot(), &nextPos);
+        totalChildCount += childCount;
+        if (childCount <= 0 || totalChildCount > MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP) {
+            // Invalid dictionary.
+            AKLOGI("Invalid dictionary. childCount: %d, totalChildCount: %d, MAX: %d",
+                    childCount, totalChildCount, MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP);
+            ASSERT(false);
+            return;
+        }
         for (int i = 0; i < childCount; i++) {
             nodeReader.fetchNodeInfoFromBufferAndGetNodeCodePoints(nextPos, MAX_WORD_LENGTH,
                     mergedNodeCodePoints);
             if (!nodeReader.isDeleted() && !nodeFilter->isFilteredOut(mergedNodeCodePoints[0])) {
-                // Push child note when the node is not deleted and not filtered out.
+                // Push child node when the node is not deleted and not filtered out.
                 childDicNodes->pushLeavingChild(dicNode, nodeReader.getNodePos(),
                         nodeReader.getChildrenPos(), nodeReader.getProbability(),
                         nodeReader.isTerminal(), nodeReader.hasChildren(),
@@ -55,13 +66,17 @@
         }
         nextPos = DynamicPatriciaTrieReadingUtils::getForwardLinkPosition(
                 binaryDictionaryInfo->getDictRoot(), nextPos);
-    } while(DynamicPatriciaTrieReadingUtils::isValidForwardLinkPosition(nextPos));
+    } while (DynamicPatriciaTrieReadingUtils::isValidForwardLinkPosition(nextPos));
 }
 
 int DynamicPatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
         const BinaryDictionaryInfo *const binaryDictionaryInfo,
         const int nodePos, const int maxCodePointCount, int *const outCodePoints,
         int *const outUnigramProbability) const {
+    if (nodePos == NOT_A_VALID_WORD_POS) {
+        *outUnigramProbability = NOT_A_PROBABILITY;
+        return 0;
+    }
     // This method traverses parent nodes from the terminal by following parent pointers; thus,
     // node code points are stored in the buffer in the reverse order.
     int reverseCodePoints[maxCodePointCount];
@@ -106,12 +121,85 @@
 int DynamicPatriciaTriePolicy::getTerminalNodePositionOfWord(
         const BinaryDictionaryInfo *const binaryDictionaryInfo, const int *const inWord,
         const int length, const bool forceLowerCaseSearch) const {
-    // TODO: Implement.
-    return NOT_A_DICT_POS;
+    int searchCodePoints[length];
+    for (int i = 0; i < length; ++i) {
+        searchCodePoints[i] = forceLowerCaseSearch ? CharUtils::toLowerCase(inWord[i]) : inWord[i];
+    }
+    int mergedNodeCodePoints[MAX_WORD_LENGTH];
+    int currentLength = 0;
+    int pos = getRootPosition();
+    DynamicPatriciaTrieNodeReader nodeReader(binaryDictionaryInfo);
+    while (currentLength <= length) {
+        // When foundMatchedNode becomes true, currentLength is increased at least once.
+        bool foundMatchedNode = false;
+        int totalChildCount = 0;
+        do {
+            const int childCount = PatriciaTrieReadingUtils::getGroupCountAndAdvancePosition(
+                    binaryDictionaryInfo->getDictRoot(), &pos);
+            totalChildCount += childCount;
+            if (childCount <= 0 || totalChildCount > MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP) {
+                // Invalid dictionary.
+                AKLOGI("Invalid dictionary. childCount: %d, totalChildCount: %d, MAX: %d",
+                        childCount, totalChildCount, MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP);
+                ASSERT(false);
+                return NOT_A_VALID_WORD_POS;
+            }
+            for (int i = 0; i < childCount; i++) {
+                nodeReader.fetchNodeInfoFromBufferAndGetNodeCodePoints(pos, MAX_WORD_LENGTH,
+                        mergedNodeCodePoints);
+                if (nodeReader.isDeleted() || nodeReader.getCodePointCount() <= 0) {
+                    // Skip deleted or empty node.
+                    pos = nodeReader.getSiblingNodePos();
+                    continue;
+                }
+                bool matched = true;
+                for (int j = 0; j < nodeReader.getCodePointCount(); ++j) {
+                    if (mergedNodeCodePoints[j] != searchCodePoints[currentLength + j]) {
+                        // Different code point is found.
+                        matched = false;
+                        break;
+                    }
+                }
+                if (matched) {
+                    currentLength += nodeReader.getCodePointCount();
+                    if (length == currentLength) {
+                        // Terminal position is found.
+                        return nodeReader.getNodePos();
+                    }
+                    if (!nodeReader.hasChildren()) {
+                        return NOT_A_VALID_WORD_POS;
+                    }
+                    foundMatchedNode = true;
+                    // Advance to the children nodes.
+                    pos = nodeReader.getChildrenPos();
+                    break;
+                }
+                // Try next sibling node.
+                pos = nodeReader.getSiblingNodePos();
+            }
+            if (foundMatchedNode) {
+                break;
+            }
+            // If the matched node is not found in the current node group, try to follow the
+            // forward link.
+            pos = DynamicPatriciaTrieReadingUtils::getForwardLinkPosition(
+                    binaryDictionaryInfo->getDictRoot(), pos);
+        } while (DynamicPatriciaTrieReadingUtils::isValidForwardLinkPosition(pos));
+        if (!foundMatchedNode) {
+            // Matched node is not found.
+            return NOT_A_VALID_WORD_POS;
+        }
+    }
+    // If we already traversed the tree further than the word is long, there means
+    // there was no match (or we would have found it).
+    return NOT_A_VALID_WORD_POS;
 }
 
 int DynamicPatriciaTriePolicy::getUnigramProbability(
         const BinaryDictionaryInfo *const binaryDictionaryInfo, const int nodePos) const {
+    if (nodePos == NOT_A_VALID_WORD_POS) {
+        return NOT_A_PROBABILITY;
+    }
     DynamicPatriciaTrieNodeReader nodeReader(binaryDictionaryInfo);
     nodeReader.fetchNodeInfoFromBuffer(nodePos);
     if (nodeReader.isDeleted() || nodeReader.isBlacklisted() || nodeReader.isNotAWord()) {
@@ -123,6 +211,9 @@
 int DynamicPatriciaTriePolicy::getShortcutPositionOfNode(
         const BinaryDictionaryInfo *const binaryDictionaryInfo,
         const int nodePos) const {
+    if (nodePos == NOT_A_VALID_WORD_POS) {
+        return NOT_A_DICT_POS;
+    }
     DynamicPatriciaTrieNodeReader nodeReader(binaryDictionaryInfo);
     nodeReader.fetchNodeInfoFromBuffer(nodePos);
     if (nodeReader.isDeleted()) {
@@ -134,6 +225,9 @@
 int DynamicPatriciaTriePolicy::getBigramsPositionOfNode(
         const BinaryDictionaryInfo *const binaryDictionaryInfo,
         const int nodePos) const {
+    if (nodePos == NOT_A_VALID_WORD_POS) {
+        return NOT_A_DICT_POS;
+    }
     DynamicPatriciaTrieNodeReader nodeReader(binaryDictionaryInfo);
     nodeReader.fetchNodeInfoFromBuffer(nodePos);
     if (nodeReader.isDeleted()) {
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
index 39dfb86..6a79771 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_policy.h
@@ -61,6 +61,7 @@
  private:
     DISALLOW_COPY_AND_ASSIGN(DynamicPatriciaTriePolicy);
     static const DynamicPatriciaTriePolicy sInstance;
+    static const int MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP;
 
     DynamicPatriciaTriePolicy() {}
     ~DynamicPatriciaTriePolicy() {}