diff --git a/SlnkDWFCom/Crypto.cpp b/SlnkDWFCom/Crypto.cpp
index 78e2a0c..b5e1984 100644
--- a/SlnkDWFCom/Crypto.cpp
+++ b/SlnkDWFCom/Crypto.cpp
@@ -114,6 +114,76 @@ STDMETHODIMP CCrypto::hex_sha1(BSTR data, BSTR* pVal)
 	return bstrString.CopyTo(pVal);
 }
 
+// Big Endian
+static inline void be32enc(void *pp, uint32_t x)
+{
+	uint8_t * p = (uint8_t *)pp;
+	p[3] = x & 0xff;
+	p[2] = (x >> 8) & 0xff;
+	p[1] = (x >> 16) & 0xff;
+	p[0] = (x >> 24) & 0xff;
+}
+
+/* F(P, S, c, i) = U1 xor U2 xor ... Uc
+* U1 = PRF(P, S || i)
+* U2 = PRF(P, U1)
+* Uc = PRF(P, Uc-1)
+*/
+#define SHA1_MAC_LEN 20
+STDMETHODIMP CCrypto::hex_pbkdf2(BSTR pPassword, BSTR pSalt, ULONG pCount, ULONG pLength, BSTR* pVal)
+{
+	CString apass(pPassword);
+	CString asalt(pSalt);
+	int saltlen = asalt.GetLength();
+	BYTE *saltbuff = (BYTE *)asalt.GetBufferSetLength(saltlen + 4); // Ruimte maken voor counter
+	int passlen = apass.GetLength();
+	BYTE *passbuff = (BYTE *)apass.GetBuffer();
+
+	size_t i;
+	uint8_t U[SHA1_MAC_LEN];
+	uint8_t T[SHA1_MAC_LEN]; // Hierin komt het XOR resultaat
+
+	CString res;
+
+	/* Iterate through the blocks. */
+	for (i = 0; i * SHA1_MAC_LEN < pLength; i++)
+	{
+		/* Generate INT(i + 1). */
+		be32enc(saltbuff + saltlen, i + 1);
+
+		/* Compute U_1 = PRF(P, S || INT(i)). */
+		CHMAC_SHA1 HMAC_SHA1;
+		HMAC_SHA1.HMAC_SHA1(saltbuff, saltlen + 4, passbuff, passlen, U);
+
+		/* T_1 = U_1 ... */
+		memcpy(T, U, SHA1_MAC_LEN);
+
+		for (uint64_t j = 2; j <= pCount; j++) 
+		{
+			/* Compute U_j. */
+			HMAC_SHA1.HMAC_SHA1(U, SHA1_MAC_LEN, passbuff, passlen, U);
+
+			/* ... xor U_j ... */
+			for (int k = 0; k < sizeof(U); k++)
+				T[k] ^= U[k];
+		}
+
+		/* Copy as many bytes as necessary into buf. */
+		int clen = pLength - i * SHA1_MAC_LEN;
+		if (clen > SHA1_MAC_LEN)
+			clen = SHA1_MAC_LEN;
+
+		for (int k = 0; k < clen; k++)
+		{
+			res = res + hex_tab[T[k] >> 4];
+			res = res + hex_tab[T[k] & 0xF];
+		}
+	}
+
+	CComBSTR bstrString(res);
+	return bstrString.CopyTo(pVal);
+}
+
 STDMETHODIMP CCrypto::hex_sha1_file(BSTR fname, BSTR* pVal)
 {
 	CSHA1 sha1;
diff --git a/SlnkDWFCom/Crypto.h b/SlnkDWFCom/Crypto.h
index 1df5199..f72b33a 100644
--- a/SlnkDWFCom/Crypto.h
+++ b/SlnkDWFCom/Crypto.h
@@ -53,6 +53,7 @@ public:
 	STDMETHOD(hex_sha1_file)(BSTR fname, BSTR* pVal);
 	STDMETHOD(hotp)(BSTR hexseed, LONGLONG counter, BYTE digits, BSTR* pVal);
 
+	STDMETHOD(hex_pbkdf2)(BSTR pPassword, BSTR pSalt, ULONG pCount, ULONG pLength, BSTR* pVal);
 };
 
 OBJECT_ENTRY_AUTO(__uuidof(Crypto), CCrypto)
diff --git a/SlnkDWFCom/SLNKDWF.idl b/SlnkDWFCom/SLNKDWF.idl
index ba7b518..2ba248b 100644
--- a/SlnkDWFCom/SLNKDWF.idl
+++ b/SlnkDWFCom/SLNKDWF.idl
@@ -392,6 +392,7 @@ interface ICrypto : IDispatch{
 	[id(3), helpstring("method hex_sha1")] HRESULT hex_sha1([in] BSTR str, [out,retval] BSTR* pVal);
 	[id(4), helpstring("method hex_sha1_file")] HRESULT hex_sha1_file([in] BSTR fname, [out,retval] BSTR* pVal);
 	[id(5), helpstring("method hotp")] HRESULT hotp([in] BSTR hexseed, [in] LONGLONG counter, [in, defaultvalue(6)] BYTE digits, [out,retval] BSTR* pVal);
+	[id(6), helpstring("method hex_pbkdf2")] HRESULT hex_pbkdf2([in] BSTR pPassword, [in] BSTR pSalt, [in] ULONG pCount, [in, defaultvalue(20)] ULONG pLength, [out, retval] BSTR* pVal);
 };
 [
 	object,
diff --git a/SlnkDWFCom/SLNKDWFVersion.h b/SlnkDWFCom/SLNKDWFVersion.h
index 02c567a..d056452 100644
--- a/SlnkDWFCom/SLNKDWFVersion.h
+++ b/SlnkDWFCom/SLNKDWFVersion.h
@@ -1,6 +1,6 @@
 // Zorg dat versies alfabetisch altijd op elkaar volgen!
 #define SLNK_MAJOR_VERSION 4
-#define SLNK_MINOR_VERSION 10
+#define SLNK_MINOR_VERSION 11
 #define SLNK_BUILD_VERSION 0
 
 // Define resource strings
diff --git a/SlnkDWFImpl/DWFFileImpl.cpp b/SlnkDWFImpl/DWFFileImpl.cpp
index 7725557..43e7e94 100644
--- a/SlnkDWFImpl/DWFFileImpl.cpp
+++ b/SlnkDWFImpl/DWFFileImpl.cpp
@@ -1,7 +1,7 @@
 // DWFFile.cpp : Implementation of CDWFFile
 
 #include "stdafx.h"
-#include "assert.h"
+//#include "assert.h"
 #include "DWFFileImpl.h"
 
 #include "myEPlotSectionImpl.h"