diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9b39b11..f4f27d9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -74,7 +74,7 @@ endif(WITH_PCRE)
 set(Boost_USE_STATIC_LIBS OFF)
 set(Boost_USE_STATIC_RUNTIME OFF)
 find_package(Boost COMPONENTS 
-      serialization unit_test_framework system filesystem program_options iostreams REQUIRED)
+      serialization unit_test_framework system filesystem program_options iostreams regex REQUIRED)
 
 # ----------------------------------------------------
 # libconfig
diff --git a/concordia/CMakeLists.txt b/concordia/CMakeLists.txt
index 727f9a1..6a971c7 100644
--- a/concordia/CMakeLists.txt
+++ b/concordia/CMakeLists.txt
@@ -6,6 +6,8 @@ foreach(dir ${ALL_DIRECTORIES})
 endforeach(dir)
 
 add_library(concordia SHARED
+  regex_replacement.cpp
+  sentence_anonymizer.cpp
   interval.cpp
   tm_matches.cpp
   anubis_search_result.cpp
diff --git a/concordia/concordia.cpp b/concordia/concordia.cpp
index 7d18b3c..30cac80 100644
--- a/concordia/concordia.cpp
+++ b/concordia/concordia.cpp
@@ -100,20 +100,20 @@ void Concordia::loadRAMIndexFromDisk() throw(ConcordiaException) {
             throw ConcordiaException("Index corrupt: empty markers file");
         }
         // generating suffix array
-        _SA = _index->generateSuffixArray(_hashGenerator, _T);
+        _SA = _index->generateSuffixArray(_T);
     } else {
         throw ConcordiaException("Index corrupt: missing files");
     }
 }
 
 void Concordia::refreshSAfromRAM() throw(ConcordiaException) {
-    _SA = _index->generateSuffixArray(_hashGenerator, _T);
+    _SA = _index->generateSuffixArray(_T);
 }
 
 
 void Concordia::_initializeIndex() throw(ConcordiaException) {
     _hashGenerator = boost::shared_ptr<HashGenerator>(
-                            new HashGenerator(_config->getWordMapFilePath()));
+                            new HashGenerator(_config));
     _T = boost::shared_ptr<std::vector<sauchar_t> >(
                                                   new std::vector<sauchar_t>);
     _markers = boost::shared_ptr<std::vector<SUFFIX_MARKER_TYPE> >(
diff --git a/concordia/concordia_index.cpp b/concordia/concordia_index.cpp
index 6f6ac42..011da29 100644
--- a/concordia/concordia_index.cpp
+++ b/concordia/concordia_index.cpp
@@ -17,7 +17,6 @@ ConcordiaIndex::~ConcordiaIndex() {
 }
 
 boost::shared_ptr<vector<saidx_t> > ConcordiaIndex::generateSuffixArray(
-                boost::shared_ptr<HashGenerator> hashGenerator,
                 boost::shared_ptr<vector<sauchar_t> > T) {
     saidx_t * SA_array = new saidx_t[T->size()];
     if (divsufsort(T->data(), SA_array, (saidx_t) T->size()) != 0) {
diff --git a/concordia/concordia_index.hpp b/concordia/concordia_index.hpp
index 6d71d98..41d9d9e 100644
--- a/concordia/concordia_index.hpp
+++ b/concordia/concordia_index.hpp
@@ -43,7 +43,6 @@ public:
                 const boost::ptr_vector<Example > & examples);
 
     boost::shared_ptr<vector<saidx_t> > generateSuffixArray(
-                boost::shared_ptr<HashGenerator> hashGenerator,
                 boost::shared_ptr<vector<sauchar_t> > T);
 
 private:
diff --git a/concordia/hash_generator.cpp b/concordia/hash_generator.cpp
index fc736f3..6014d01 100644
--- a/concordia/hash_generator.cpp
+++ b/concordia/hash_generator.cpp
@@ -5,10 +5,11 @@
 #include <boost/algorithm/string.hpp>
 #include <fstream>
 
-HashGenerator::HashGenerator(const string & wordMapFilePath)
+HashGenerator::HashGenerator(boost::shared_ptr<ConcordiaConfig> config)
                                          throw(ConcordiaException) :
-    _wordMapFilePath(wordMapFilePath),
-    _wordMap(boost::shared_ptr<WordMap>(new WordMap)) {
+    _wordMapFilePath(config->getWordMapFilePath()),
+    _wordMap(boost::shared_ptr<WordMap>(new WordMap)),
+    _sentenceAnonymizer(boost::shared_ptr<SentenceAnonymizer>(new SentenceAnonymizer(config))) {
     if (boost::filesystem::exists(_wordMapFilePath)) {
         ifstream ifs(_wordMapFilePath.c_str(), std::ios::binary);
         boost::archive::binary_iarchive ia(ifs);
diff --git a/concordia/hash_generator.hpp b/concordia/hash_generator.hpp
index 450ce6d..982df2d 100644
--- a/concordia/hash_generator.hpp
+++ b/concordia/hash_generator.hpp
@@ -8,6 +8,8 @@
 #include <boost/algorithm/string/predicate.hpp>
 #include "concordia/word_map.hpp"
 #include "concordia/common/config.hpp"
+#include "concordia/sentence_anonymizer.hpp"
+#include "concordia/concordia_config.hpp"
 #include "concordia/concordia_exception.hpp"
 
 
@@ -20,8 +22,8 @@ using namespace std;
 
 class HashGenerator {
 public:
-    explicit HashGenerator(const string & wordMapFilePath)
-                                    throw(ConcordiaException);
+    explicit HashGenerator(boost::shared_ptr<ConcordiaConfig> config)
+                                            throw(ConcordiaException);
 
     /*! Destructor.
     */
@@ -35,6 +37,8 @@ public:
 
 private:
     boost::shared_ptr<WordMap> _wordMap;
+    
+    boost::shared_ptr<SentenceAnonymizer> _sentenceAnonymizer;
 
     string _wordMapFilePath;
 };
diff --git a/concordia/regex_replacement.cpp b/concordia/regex_replacement.cpp
new file mode 100644
index 0000000..cc09964
--- /dev/null
+++ b/concordia/regex_replacement.cpp
@@ -0,0 +1,31 @@
+#include "concordia/regex_replacement.hpp"
+#include <sstream>
+#include <boost/exception/all.hpp>
+#include <boost/throw_exception.hpp>
+
+RegexReplacement::RegexReplacement(string patternString, string replacement)
+                                         throw(ConcordiaException):
+                                         _replacement(replacement) {
+    try {
+        _pattern = boost::regex(patternString);
+    } catch ( const std::exception & e ) {
+        stringstream ss;
+        
+        ss << "Bad regex pattern: " << patternString <<
+             " Detailed info: " << e.what();
+             
+        if ( std::string const * extra  = boost::get_error_info<my_tag_error_info>(e) ) {
+            ss << *extra;
+        }
+        throw ConcordiaException(ss.str());
+    }
+}
+
+RegexReplacement::~RegexReplacement() {
+}
+
+string RegexReplacement::apply(const string & text) {
+    return boost::regex_replace(text, _pattern, _replacement,
+                    boost::match_default | boost::format_all);
+}
+
diff --git a/concordia/regex_replacement.hpp b/concordia/regex_replacement.hpp
new file mode 100644
index 0000000..88c33ce
--- /dev/null
+++ b/concordia/regex_replacement.hpp
@@ -0,0 +1,37 @@
+#ifndef REGEX_REPLACEMENT_HDR
+#define REGEX_REPLACEMENT_HDR
+
+#include <string>
+#include "concordia/common/config.hpp"
+#include "concordia/concordia_exception.hpp"
+#include <boost/shared_ptr.hpp>
+#include <boost/regex.hpp>
+
+
+/*!
+  Class for replacing string occurences.
+
+*/
+
+using namespace std;
+
+typedef boost::error_info<struct my_tag,std::string> my_tag_error_info;
+
+class RegexReplacement {
+public:
+    explicit RegexReplacement(string patternString, string replacement)
+                                              throw(ConcordiaException);
+
+    /*! Destructor.
+    */
+    virtual ~RegexReplacement();
+    
+    string apply(const string & text);
+
+private:
+    boost::regex _pattern;
+    
+    string _replacement;    
+};
+
+#endif
diff --git a/concordia/sentence_anonymizer.cpp b/concordia/sentence_anonymizer.cpp
new file mode 100644
index 0000000..9b530bc
--- /dev/null
+++ b/concordia/sentence_anonymizer.cpp
@@ -0,0 +1,13 @@
+#include "concordia/sentence_anonymizer.hpp"
+
+SentenceAnonymizer::SentenceAnonymizer(boost::shared_ptr<ConcordiaConfig> config)
+                                         throw(ConcordiaException) {
+}
+
+SentenceAnonymizer::~SentenceAnonymizer() {
+}
+
+string SentenceAnonymizer::anonymize(const string & sentence) {
+
+}
+
diff --git a/concordia/sentence_anonymizer.hpp b/concordia/sentence_anonymizer.hpp
new file mode 100644
index 0000000..6d0ded3
--- /dev/null
+++ b/concordia/sentence_anonymizer.hpp
@@ -0,0 +1,32 @@
+#ifndef SENTENCE_ANONYMIZER_HDR
+#define SENTENCE_ANONYMIZER_HDR
+
+#include <string>
+#include "concordia/common/config.hpp"
+#include "concordia/concordia_config.hpp"
+#include "concordia/concordia_exception.hpp"
+#include <boost/shared_ptr.hpp>
+
+
+/*!
+  Class for anonymizing sentence before adding to index.
+
+*/
+
+using namespace std;
+
+class SentenceAnonymizer {
+public:
+    explicit SentenceAnonymizer(boost::shared_ptr<ConcordiaConfig> config)
+                                                 throw(ConcordiaException);
+
+    /*! Destructor.
+    */
+    virtual ~SentenceAnonymizer();
+    
+    string anonymize(const string & sentence);
+
+private:
+};
+
+#endif
diff --git a/concordia/t/CMakeLists.txt b/concordia/t/CMakeLists.txt
index bdd3c92..054178c 100644
--- a/concordia/t/CMakeLists.txt
+++ b/concordia/t/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_library(concordia-tests
+  test_regex_replacement.cpp
   test_example.cpp
   test_tm_matches.cpp
   test_interval.cpp
diff --git a/concordia/t/test_concordia_config.cpp b/concordia/t/test_concordia_config.cpp
index 4af8602..5fc66c0 100644
--- a/concordia/t/test_concordia_config.cpp
+++ b/concordia/t/test_concordia_config.cpp
@@ -15,10 +15,10 @@ BOOST_AUTO_TEST_CASE( ConfigParameters )
 {
     ConcordiaConfig config(TestResourcesManager::getTestConcordiaConfigFilePath("concordia-mock.cfg"));
     BOOST_CHECK_EQUAL( config.getPuddleTagsetFilePath() , "puddle/tagset.txt" );
-    BOOST_CHECK_EQUAL( config.getWordMapFilePath() , "tmp/wm.bin" );
-    BOOST_CHECK_EQUAL( config.getHashedIndexFilePath() , "tmp/hi.bin" );
-    BOOST_CHECK_EQUAL( config.getMarkersFilePath() , "tmp/ma.bin" );
-    BOOST_CHECK_EQUAL( config.getSuffixArrayFilePath() , "tmp/sa.bin" );
+    BOOST_CHECK_EQUAL( config.getWordMapFilePath() , "/tmp/wm.bin" );
+    BOOST_CHECK_EQUAL( config.getHashedIndexFilePath() , "/tmp/hi.bin" );
+    BOOST_CHECK_EQUAL( config.getMarkersFilePath() , "/tmp/ma.bin" );
+    BOOST_CHECK_EQUAL( config.getSuffixArrayFilePath() , "/tmp/sa.bin" );
 }
 
 BOOST_AUTO_TEST_CASE( NonexistentConfigTest )
diff --git a/concordia/t/test_concordia_index.cpp b/concordia/t/test_concordia_index.cpp
index 3efeb64..afdcf34 100644
--- a/concordia/t/test_concordia_index.cpp
+++ b/concordia/t/test_concordia_index.cpp
@@ -14,8 +14,6 @@ BOOST_AUTO_TEST_SUITE(concordia_index)
 
 BOOST_AUTO_TEST_CASE( SuffixArrayGenerationTest )
 {
-    boost::shared_ptr<HashGenerator> hashGenerator (new HashGenerator("nonexistent"));
-    
     ConcordiaIndex index(TestResourcesManager::getTestFilePath("temp","test_hash_index.bin"),
                          TestResourcesManager::getTestFilePath("temp","test_markers.bin"));
     boost::shared_ptr<vector<sauchar_t> > T = boost::shared_ptr<vector<sauchar_t> >(new vector<sauchar_t>());
@@ -36,7 +34,7 @@ BOOST_AUTO_TEST_CASE( SuffixArrayGenerationTest )
     //    n: 0 1 2 3 4 5 6 7 8
     //SA[n]: 0 3 1 7 4 2 8 5 6
 
-    boost::shared_ptr<std::vector<saidx_t> > SA = index.generateSuffixArray(hashGenerator, T);
+    boost::shared_ptr<std::vector<saidx_t> > SA = index.generateSuffixArray(T);
 
     boost::shared_ptr<vector<saidx_t> > expectedSA = boost::shared_ptr<vector<saidx_t> >(new vector<saidx_t>());
     expectedSA->push_back(0);
@@ -53,8 +51,6 @@ BOOST_AUTO_TEST_CASE( SuffixArrayGenerationTest )
 
 BOOST_AUTO_TEST_CASE( SuffixArrayGenerationTest2 )
 {
-    boost::shared_ptr<HashGenerator> hashGenerator (new HashGenerator("nonexistent"));
-    
     ConcordiaIndex index(TestResourcesManager::getTestFilePath("temp","test_hash_index.bin"),
                          TestResourcesManager::getTestFilePath("temp","test_markers.bin"));
     boost::shared_ptr<vector<sauchar_t> > T = boost::shared_ptr<vector<sauchar_t> >(new vector<sauchar_t>());
@@ -79,7 +75,7 @@ BOOST_AUTO_TEST_CASE( SuffixArrayGenerationTest2 )
     //    n: 0  1  2  3  4  5  6  7  8  9 10 11
     //SA[n]: 0  4  1  9  5  2 10  6  8 11  3  7 
 
-    boost::shared_ptr<std::vector<saidx_t> > SA = index.generateSuffixArray(hashGenerator, T);
+    boost::shared_ptr<std::vector<saidx_t> > SA = index.generateSuffixArray(T);
 
     boost::shared_ptr<vector<saidx_t> > expectedSA = boost::shared_ptr<vector<saidx_t> >(new vector<saidx_t>());
     expectedSA->push_back(0);
diff --git a/concordia/t/test_hash_generator.cpp b/concordia/t/test_hash_generator.cpp
index 6df7cfe..3fc4e44 100644
--- a/concordia/t/test_hash_generator.cpp
+++ b/concordia/t/test_hash_generator.cpp
@@ -3,10 +3,11 @@
 #include <string>
 #include <sstream>
 
+#include <boost/shared_ptr.hpp>
 #include "concordia/common/config.hpp"
 #include "concordia/hash_generator.hpp"
+#include "tests/common/test_resources_manager.hpp"
 
-#define TEST_WORD_MAP_PATH "/tmp/test_word_map.bin"
 
 using namespace std;
 
@@ -14,11 +15,13 @@ BOOST_AUTO_TEST_SUITE(hash_generator)
 
 BOOST_AUTO_TEST_CASE( SimpleHashTest )
 {
-    if (boost::filesystem::exists(TEST_WORD_MAP_PATH)) {
-        boost::filesystem::remove(TEST_WORD_MAP_PATH);      
+    boost::shared_ptr<ConcordiaConfig> config(new ConcordiaConfig(TestResourcesManager::getTestConcordiaConfigFilePath("concordia-mock.cfg")));
+    
+    if (boost::filesystem::exists(config->getWordMapFilePath())) {
+        boost::filesystem::remove(config->getWordMapFilePath());      
     } 
     
-    HashGenerator hashGenerator = HashGenerator(TEST_WORD_MAP_PATH);
+    HashGenerator hashGenerator = HashGenerator(config);
 
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > hash = hashGenerator.generateHash("Ala ma kota");
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > expected(new vector<INDEX_CHARACTER_TYPE>());
@@ -31,11 +34,13 @@ BOOST_AUTO_TEST_CASE( SimpleHashTest )
 
 BOOST_AUTO_TEST_CASE( TooLongHashTest )
 {
-    if (boost::filesystem::exists(TEST_WORD_MAP_PATH)) {
-        boost::filesystem::remove(TEST_WORD_MAP_PATH);      
+    boost::shared_ptr<ConcordiaConfig> config(new ConcordiaConfig(TestResourcesManager::getTestConcordiaConfigFilePath("concordia-mock.cfg")));
+    
+    if (boost::filesystem::exists(config->getWordMapFilePath())) {
+        boost::filesystem::remove(config->getWordMapFilePath());      
     } 
     
-    HashGenerator hashGenerator = HashGenerator(TEST_WORD_MAP_PATH);
+    HashGenerator hashGenerator = HashGenerator(config);
 
     stringstream ss;
     for (int i=0;i<256;i++) {
@@ -60,11 +65,14 @@ BOOST_AUTO_TEST_CASE( TooLongHashTest )
 
 BOOST_AUTO_TEST_CASE( HashSerializationTest )
 {
-    if (boost::filesystem::exists(TEST_WORD_MAP_PATH)) {
-        boost::filesystem::remove(TEST_WORD_MAP_PATH);      
+    boost::shared_ptr<ConcordiaConfig> config(new ConcordiaConfig(TestResourcesManager::getTestConcordiaConfigFilePath("concordia-mock.cfg")));
+    
+    if (boost::filesystem::exists(config->getWordMapFilePath())) {
+        boost::filesystem::remove(config->getWordMapFilePath());      
     } 
+    
+    HashGenerator hashGenerator1 = HashGenerator(config);
 
-    HashGenerator hashGenerator1 = HashGenerator(TEST_WORD_MAP_PATH);
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > hash1 = hashGenerator1.generateHash("Ala ma kota");
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > expected1(new vector<INDEX_CHARACTER_TYPE>());
     expected1->push_back(0);
@@ -74,7 +82,7 @@ BOOST_AUTO_TEST_CASE( HashSerializationTest )
 
     hashGenerator1.serializeWordMap();
    
-    HashGenerator hashGenerator2 = HashGenerator(TEST_WORD_MAP_PATH);
+    HashGenerator hashGenerator2 = HashGenerator(config);
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > hash2 = hashGenerator2.generateHash("Ala ma psa");
     boost::shared_ptr<vector<INDEX_CHARACTER_TYPE> > expected2(new vector<INDEX_CHARACTER_TYPE>());
     expected2->push_back(0);
@@ -82,7 +90,7 @@ BOOST_AUTO_TEST_CASE( HashSerializationTest )
     expected2->push_back(3);
     BOOST_CHECK_EQUAL_COLLECTIONS(hash2->begin(), hash2->end(), expected2->begin(), expected2->end());
 
-    boost::filesystem::remove(TEST_WORD_MAP_PATH);       
+    boost::filesystem::remove(config->getWordMapFilePath());       
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/concordia/t/test_regex_replacement.cpp b/concordia/t/test_regex_replacement.cpp
new file mode 100644
index 0000000..02a6065
--- /dev/null
+++ b/concordia/t/test_regex_replacement.cpp
@@ -0,0 +1,42 @@
+#include "tests/unit-tests/unit_tests_globals.hpp"
+#include "concordia/regex_replacement.hpp"
+#include "concordia/common/config.hpp"
+#include <boost/algorithm/string/predicate.hpp>
+
+using namespace std;
+
+BOOST_AUTO_TEST_SUITE(regex_replacement)
+
+BOOST_AUTO_TEST_CASE( SimpleReplacement )
+{
+    RegexReplacement rr("a","b");
+    BOOST_CHECK_EQUAL(rr.apply("xxxxxxxaxxxaxxaxaxa"),"xxxxxxxbxxxbxxbxbxb");
+}
+
+BOOST_AUTO_TEST_CASE( BadRegex )
+{
+    bool exceptionThrown = false;
+    string message = "";
+    try {
+        RegexReplacement rr("+a","b");
+    } catch (ConcordiaException & e) {
+        exceptionThrown = true;
+        message = e.what();
+    }    
+    BOOST_CHECK_EQUAL(exceptionThrown, true);    
+    BOOST_CHECK_EQUAL(boost::starts_with(message, "Bad regex pattern"), true);    
+}
+
+BOOST_AUTO_TEST_CASE( WeirdSymbolsReplacement )
+{
+    RegexReplacement rr("['\"\\\\.]","");
+    BOOST_CHECK_EQUAL(rr.apply("Don't stop believin' \\ Hold on to the feelin'."),"Dont stop believin  Hold on to the feelin");
+}
+
+BOOST_AUTO_TEST_CASE( BackrefReplacement )
+{
+    RegexReplacement rr("(\\d+)","the number: \\1");
+    BOOST_CHECK_EQUAL(rr.apply("This is 12 and this is 812."),"This is the number: 12 and this is the number: 812.");
+}
+
+BOOST_AUTO_TEST_SUITE_END()
diff --git a/tests/resources/concordia-config/concordia-mock.cfg b/tests/resources/concordia-config/concordia-mock.cfg
index 37bd27b..8170e3f 100644
--- a/tests/resources/concordia-config/concordia-mock.cfg
+++ b/tests/resources/concordia-config/concordia-mock.cfg
@@ -6,12 +6,12 @@
 #Path to the Puddle tagset
 puddle_tagset_path = "puddle/tagset.txt";
 
-word_map_path = "tmp/wm.bin"
+word_map_path = "/tmp/wm.bin"
 
-hashed_index_path = "tmp/hi.bin"
+hashed_index_path = "/tmp/hi.bin"
 
-markers_path = "tmp/ma.bin"
+markers_path = "/tmp/ma.bin"
 
-suffix_array_path = "tmp/sa.bin"
+suffix_array_path = "/tmp/sa.bin"
 
 ### eof