diff --git a/Zip/src/Compress.cpp b/Zip/src/Compress.cpp
index 65af92574..dab372cf9 100644
--- a/Zip/src/Compress.cpp
+++ b/Zip/src/Compress.cpp
@@ -80,7 +80,7 @@ void Compress::addEntry(std::istream& in, const Poco::DateTime& lastModifiedAt,
 	if (hdr.searchCRCAndSizesAfterData())
 		_offset += ZipDataInfo::getFullHeaderSize();
 	_files.insert(std::make_pair(fileName.toString(Poco::Path::PATH_UNIX), hdr));
-	poco_assert (_out);
+	if (!_out) throw Poco::IOException("Bad output stream");
 	ZipFileInfo nfo(hdr);
 	nfo.setOffset(localHeaderOffset);
 	_infos.insert(std::make_pair(fileName.toString(Poco::Path::PATH_UNIX), nfo));
@@ -145,7 +145,7 @@ void Compress::addFileRaw(std::istream& in, const ZipLocalFileHeader& h, const P
 	if (hdr.searchCRCAndSizesAfterData())
 		_offset += ZipDataInfo::getFullHeaderSize();
 	_files.insert(std::make_pair(fileName.toString(Poco::Path::PATH_UNIX), hdr));
-	poco_assert (_out);
+	if (!_out) throw Poco::IOException("Bad output stream");
 	ZipFileInfo nfo(hdr);
 	nfo.setOffset(localHeaderOffset);
 	_infos.insert(std::make_pair(fileName.toString(Poco::Path::PATH_UNIX), nfo));
@@ -213,7 +213,7 @@ void Compress::addDirectory(const Poco::Path& entryName, const Poco::DateTime& l
 	if (hdr.searchCRCAndSizesAfterData())
 		_offset += ZipDataInfo::getFullHeaderSize();
 	_files.insert(std::make_pair(entryName.toString(Poco::Path::PATH_UNIX), hdr));
-	poco_assert (_out);
+	if (!_out) throw Poco::IOException("Bad output stream");
 	ZipFileInfo nfo(hdr);
 	nfo.setOffset(localHeaderOffset);
 	_infos.insert(std::make_pair(entryName.toString(Poco::Path::PATH_UNIX), nfo));
@@ -294,8 +294,7 @@ ZipArchive Compress::close()
 		centralDirSize += entrySize;
 		_offset += entrySize;
 	}
-	poco_assert (_out);
-
+	if (!_out) throw Poco::IOException("Bad output stream");
 	
 	Poco::UInt16 numEntries = static_cast<Poco::UInt16>(_infos.size());
 	ZipArchiveInfo central;
diff --git a/Zip/src/Decompress.cpp b/Zip/src/Decompress.cpp
index 2f94fa949..e01f47e9d 100644
--- a/Zip/src/Decompress.cpp
+++ b/Zip/src/Decompress.cpp
@@ -39,7 +39,7 @@ Decompress::Decompress(std::istream& in, const Poco::Path& outputDir, bool flatt
 {
 	_outDir.makeAbsolute();
 	_outDir.makeDirectory();
-	poco_assert (_in.good());
+	if (!_in.good()) throw Poco::IOException("Bad input stream");
 	Poco::File tmp(_outDir);
 	if (!tmp.exists())
 	{
diff --git a/Zip/src/ZipArchiveInfo.cpp b/Zip/src/ZipArchiveInfo.cpp
index c76a53dab..e77b7f5e7 100644
--- a/Zip/src/ZipArchiveInfo.cpp
+++ b/Zip/src/ZipArchiveInfo.cpp
@@ -58,12 +58,16 @@ void ZipArchiveInfo::parse(std::istream& inp, bool assumeHeaderRead)
 	if (!assumeHeaderRead)
 	{
 		inp.read(_rawInfo, ZipCommon::HEADER_SIZE);
+		if (inp.gcount() != ZipCommon::HEADER_SIZE)
+			throw Poco::IOException("Failed to read archive info header");
+		if (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) != 0)
+			throw Poco::DataFormatException("Bad archive info header");
 	}
 	else
 	{
 		std::memcpy(_rawInfo, HEADER, ZipCommon::HEADER_SIZE);
 	}
-	poco_assert (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) == 0);
+		
 	// read the rest of the header
 	inp.read(_rawInfo + ZipCommon::HEADER_SIZE, FULLHEADER_SIZE - ZipCommon::HEADER_SIZE);
 	Poco::UInt16 len = getZipCommentSize();
diff --git a/Zip/src/ZipDataInfo.cpp b/Zip/src/ZipDataInfo.cpp
index 3d5197a0c..8545f3c48 100644
--- a/Zip/src/ZipDataInfo.cpp
+++ b/Zip/src/ZipDataInfo.cpp
@@ -15,6 +15,7 @@
 
 
 #include "Poco/Zip/ZipDataInfo.h"
+#include "Poco/Exception.h"
 #include <istream>
 #include <cstring>
 
@@ -41,10 +42,17 @@ ZipDataInfo::ZipDataInfo(std::istream& in, bool assumeHeaderRead):
 	_valid(false)
 {
 	if (assumeHeaderRead)
+	{
 		std::memcpy(_rawInfo, HEADER, ZipCommon::HEADER_SIZE);
+	}
 	else
+	{
 		in.read(_rawInfo, ZipCommon::HEADER_SIZE);
-	poco_assert (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) == 0);
+		if (in.gcount() != ZipCommon::HEADER_SIZE)
+			throw Poco::IOException("Failed to read data info header");
+		if (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) != 0)
+			throw Poco::DataFormatException("Bad data info header");
+	}
 	// now copy the rest of the header
 	in.read(_rawInfo+ZipCommon::HEADER_SIZE, FULLHEADER_SIZE - ZipCommon::HEADER_SIZE);
 	_valid = (!in.eof() && in.good());
diff --git a/Zip/src/ZipFileInfo.cpp b/Zip/src/ZipFileInfo.cpp
index 62e14cf5b..18ef3816a 100644
--- a/Zip/src/ZipFileInfo.cpp
+++ b/Zip/src/ZipFileInfo.cpp
@@ -85,12 +85,16 @@ void ZipFileInfo::parse(std::istream& inp, bool assumeHeaderRead)
 	if (!assumeHeaderRead)
 	{
 		inp.read(_rawInfo, ZipCommon::HEADER_SIZE);
+		if (inp.gcount() != ZipCommon::HEADER_SIZE)
+			throw Poco::IOException("Failed to read file info header");
+		if (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) != 0)
+			throw Poco::DataFormatException("Bad file info header");
 	}
 	else
 	{
 		std::memcpy(_rawInfo, HEADER, ZipCommon::HEADER_SIZE);
 	}
-	poco_assert (std::memcmp(_rawInfo, HEADER, ZipCommon::HEADER_SIZE) == 0);
+
 	// read the rest of the header
 	inp.read(_rawInfo + ZipCommon::HEADER_SIZE, FULLHEADER_SIZE - ZipCommon::HEADER_SIZE);
 	_crc32 = getCRCFromHeader();
diff --git a/Zip/src/ZipLocalFileHeader.cpp b/Zip/src/ZipLocalFileHeader.cpp
index 645775767..00c02ba8d 100644
--- a/Zip/src/ZipLocalFileHeader.cpp
+++ b/Zip/src/ZipLocalFileHeader.cpp
@@ -103,18 +103,22 @@ void ZipLocalFileHeader::parse(std::istream& inp, bool assumeHeaderRead)
 	if (!assumeHeaderRead)
 	{
 		inp.read(_rawHeader, ZipCommon::HEADER_SIZE);
+		if (inp.gcount() != ZipCommon::HEADER_SIZE)
+			throw Poco::IOException("Failed to read local file header");
+		if (std::memcmp(_rawHeader, HEADER, ZipCommon::HEADER_SIZE) != 0)
+			throw Poco::DataFormatException("Bad local file header");
 	}
 	else
 	{
 		std::memcpy(_rawHeader, HEADER, ZipCommon::HEADER_SIZE);
 	}
-	poco_assert (std::memcmp(_rawHeader, HEADER, ZipCommon::HEADER_SIZE) == 0);
+
 	// read the rest of the header
 	inp.read(_rawHeader + ZipCommon::HEADER_SIZE, FULLHEADER_SIZE - ZipCommon::HEADER_SIZE);
 	if (!(_rawHeader[VERSION_POS + 1]>= ZipCommon::HS_FAT && _rawHeader[VERSION_POS + 1] < ZipCommon::HS_UNUSED))
-		throw Poco::DataFormatException("bad ZIP file header", "invalid version");
+		throw Poco::DataFormatException("Bad local file header", "invalid version");
 	if (ZipUtil::get16BitValue(_rawHeader, COMPR_METHOD_POS) >= ZipCommon::CM_UNUSED)
-		throw Poco::DataFormatException("bad ZIP file header", "invalid compression method");
+		throw Poco::DataFormatException("Bad local file header", "invalid compression method");
 	parseDateTime();
 	Poco::UInt16 len = getFileNameLength();
 	if (len > 0)
diff --git a/Zip/src/ZipManipulator.cpp b/Zip/src/ZipManipulator.cpp
index 5fc00e9ae..73e8e7e1c 100644
--- a/Zip/src/ZipManipulator.cpp
+++ b/Zip/src/ZipManipulator.cpp
@@ -111,7 +111,7 @@ const ZipLocalFileHeader& ZipManipulator::getForChange(const std::string& zipPat
 {
 	ZipArchive::FileHeaders::const_iterator it = _in->findHeader(zipPath);
 	if (it == _in->headerEnd())
-		throw ZipManipulationException("entry not found: " + zipPath);
+		throw ZipManipulationException("Entry not found: " + zipPath);
 
 	if (_changes.find(zipPath) != _changes.end())
 		throw ZipManipulationException("A change request exists already for entry " + zipPath);