diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 829adaf..cbcb5b0 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -1,6 +1,8 @@
 /**
  * \file x509.h
  *
+ * \brief X.509 certificate and private key decoding
+ *
  *  Copyright (C) 2006-2010, Brainspark B.V.
  *
  *  This file is part of PolarSSL (http://www.polarssl.org)
@@ -27,59 +29,80 @@
 
 #include "polarssl/rsa.h"
 
-/*
- * ASN1 Error codes
- *
- * These error codes will be OR'ed to X509 error codes for
- * higher error granularity.
+/** 
+ * @addtogroup x509_module
+ * @{ 
  */
-#define POLARSSL_ERR_ASN1_OUT_OF_DATA                      0x0014
-#define POLARSSL_ERR_ASN1_UNEXPECTED_TAG                   0x0016
-#define POLARSSL_ERR_ASN1_INVALID_LENGTH                   0x0018
-#define POLARSSL_ERR_ASN1_LENGTH_MISMATCH                  0x001A
-#define POLARSSL_ERR_ASN1_INVALID_DATA                     0x001C
-
-/*
- * X509 Error codes
+ 
+/**
+ * @name ASN1 Error codes
+ * These error codes are OR'ed to X509 error codes for
+ * higher error granularity. 
+ * ASN1 is a standard to specify data structures.
+ * @{
  */
-#define POLARSSL_ERR_X509_FEATURE_UNAVAILABLE              -0x0020
-#define POLARSSL_ERR_X509_CERT_INVALID_PEM                 -0x0040
-#define POLARSSL_ERR_X509_CERT_INVALID_FORMAT              -0x0060
-#define POLARSSL_ERR_X509_CERT_INVALID_VERSION             -0x0080
-#define POLARSSL_ERR_X509_CERT_INVALID_SERIAL              -0x00A0
-#define POLARSSL_ERR_X509_CERT_INVALID_ALG                 -0x00C0
-#define POLARSSL_ERR_X509_CERT_INVALID_NAME                -0x00E0
-#define POLARSSL_ERR_X509_CERT_INVALID_DATE                -0x0100
-#define POLARSSL_ERR_X509_CERT_INVALID_PUBKEY              -0x0120
-#define POLARSSL_ERR_X509_CERT_INVALID_SIGNATURE           -0x0140
-#define POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS          -0x0160
-#define POLARSSL_ERR_X509_CERT_UNKNOWN_VERSION             -0x0180
-#define POLARSSL_ERR_X509_CERT_UNKNOWN_SIG_ALG             -0x01A0
-#define POLARSSL_ERR_X509_CERT_UNKNOWN_PK_ALG              -0x01C0
-#define POLARSSL_ERR_X509_CERT_SIG_MISMATCH                -0x01E0
-#define POLARSSL_ERR_X509_CERT_VERIFY_FAILED               -0x0200
-#define POLARSSL_ERR_X509_KEY_INVALID_PEM                  -0x0220
-#define POLARSSL_ERR_X509_KEY_INVALID_VERSION              -0x0240
-#define POLARSSL_ERR_X509_KEY_INVALID_FORMAT               -0x0260
-#define POLARSSL_ERR_X509_KEY_INVALID_ENC_IV               -0x0280
-#define POLARSSL_ERR_X509_KEY_UNKNOWN_ENC_ALG              -0x02A0
-#define POLARSSL_ERR_X509_KEY_PASSWORD_REQUIRED            -0x02C0
-#define POLARSSL_ERR_X509_KEY_PASSWORD_MISMATCH            -0x02E0
-#define POLARSSL_ERR_X509_POINT_ERROR                      -0x0300
-#define POLARSSL_ERR_X509_VALUE_TO_LENGTH                  -0x0320
+#define POLARSSL_ERR_ASN1_OUT_OF_DATA                      0x0014   /**< Out of data when parsing an ASN1 data structure. */
+#define POLARSSL_ERR_ASN1_UNEXPECTED_TAG                   0x0016   /**< ASN1 tag was of an unexpected value. */
+#define POLARSSL_ERR_ASN1_INVALID_LENGTH                   0x0018   /**< Error when trying to determine the length or invalid length. */
+#define POLARSSL_ERR_ASN1_LENGTH_MISMATCH                  0x001A   /**< Actual length differs from expected length. */
+#define POLARSSL_ERR_ASN1_INVALID_DATA                     0x001C   /**< Data is invalid. (not used) */
+/* @} name */
 
-/*
- * X509 Verify codes
+/** 
+ * @name X509 Error codes
+ * @{
  */
-#define BADCERT_EXPIRED                 1
-#define BADCERT_REVOKED                 2
-#define BADCERT_CN_MISMATCH             4
-#define BADCERT_NOT_TRUSTED             8
-#define BADCRL_NOT_TRUSTED             16
-#define BADCRL_EXPIRED                 32
+#define POLARSSL_ERR_X509_FEATURE_UNAVAILABLE              -0x0020  /**< Unavailable feature, e.g. RSA hashing/encryption combination. */
+#define POLARSSL_ERR_X509_CERT_INVALID_PEM                 -0x0040  /**< The PEM-encoded certificate contains invalid elements, e.g. invalid character. */ 
+#define POLARSSL_ERR_X509_CERT_INVALID_FORMAT              -0x0060  /**< The certificate format is invalid, e.g. different type expected. */
+#define POLARSSL_ERR_X509_CERT_INVALID_VERSION             -0x0080  /**< The certificate version element is invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_SERIAL              -0x00A0  /**< The serial tag or value is invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_ALG                 -0x00C0  /**< The algorithm tag or value is invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_NAME                -0x00E0  /**< The name tag or value is invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_DATE                -0x0100  /**< The date tag or value is invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_PUBKEY              -0x0120  /**< The pubkey tag or value is invalid (only RSA is supported). */
+#define POLARSSL_ERR_X509_CERT_INVALID_SIGNATURE           -0x0140  /**< The signature tag or value invalid. */
+#define POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS          -0x0160  /**< The extension tag or value is invalid. */
+#define POLARSSL_ERR_X509_CERT_UNKNOWN_VERSION             -0x0180  /**< Certificate or CRL has an unsupported version number. */
+#define POLARSSL_ERR_X509_CERT_UNKNOWN_SIG_ALG             -0x01A0  /**< Signature algorithm (oid) is unsupported. */
+#define POLARSSL_ERR_X509_CERT_UNKNOWN_PK_ALG              -0x01C0  /**< Public key algorithm is unsupported (only RSA is supported). */
+#define POLARSSL_ERR_X509_CERT_SIG_MISMATCH                -0x01E0  /**< Certificate signature algorithms do not match. (see \c ::x509_cert sig_oid) */
+#define POLARSSL_ERR_X509_CERT_VERIFY_FAILED               -0x0200  /**< Certificate verification failed, e.g. CRL, CA or signature check failed. */
+#define POLARSSL_ERR_X509_KEY_INVALID_PEM                  -0x0220  /**< PEM key string is not as expected. */
+#define POLARSSL_ERR_X509_KEY_INVALID_VERSION              -0x0240  /**< Unsupported RSA key version */
+#define POLARSSL_ERR_X509_KEY_INVALID_FORMAT               -0x0260  /**< Invalid RSA key tag or value. */
+#define POLARSSL_ERR_X509_KEY_INVALID_ENC_IV               -0x0280  /**< RSA IV is not in hex-format. */
+#define POLARSSL_ERR_X509_KEY_UNKNOWN_ENC_ALG              -0x02A0  /**< Unsupported key encryption algorithm. */
+#define POLARSSL_ERR_X509_KEY_PASSWORD_REQUIRED            -0x02C0  /**< Private key password can't be empty. */
+#define POLARSSL_ERR_X509_KEY_PASSWORD_MISMATCH            -0x02E0  /**< Given private key password does not allow for correct decryption. */
+#define POLARSSL_ERR_X509_POINT_ERROR                      -0x0300  /**< Not used. */
+#define POLARSSL_ERR_X509_VALUE_TO_LENGTH                  -0x0320  /**< Not used. */
+/* @} name */
 
-/*
- * DER constants
+
+/**
+ * @name X509 Verify codes
+ * @{
+ */
+#define BADCERT_EXPIRED                 1   /**< The certificate validity has expired. */
+#define BADCERT_REVOKED                 2   /**< The certificate has been revoked (is on a CRL). */
+#define BADCERT_CN_MISMATCH             4   /**< The certificate Common Name (CN) does not match with the expected CN. */
+#define BADCERT_NOT_TRUSTED             8   /**< The certificate is not correctly signed by the trusted CA. */
+#define BADCRL_NOT_TRUSTED             16   /**< CRL is not correctly signed by the trusted CA. */
+#define BADCRL_EXPIRED                 32   /**< CRL is expired. */
+/* @} name */
+
+
+/**
+ * @name DER constants
+ * These constants comply with DER encoded the ANS1 type tags.
+ * DER encoding uses hexadecimal representation.
+ * An example DER sequence is:\n
+ * - 0x02 -- tag indicating INTEGER
+ * - 0x01 -- length in octets
+ * - 0x05 -- value
+ * Such sequences are typically read into \c ::x509_buf.
+ * @{
  */
 #define ASN1_BOOLEAN                 0x01
 #define ASN1_INTEGER                 0x02
@@ -100,6 +123,8 @@
 #define ASN1_PRIMITIVE               0x00
 #define ASN1_CONSTRUCTED             0x20
 #define ASN1_CONTEXT_SPECIFIC        0x80
+/* @} name */
+/* @} addtogroup x509_module */
 
 /*
  * various object identifiers
@@ -126,68 +151,89 @@
 #define OID_PKCS9               "\x2A\x86\x48\x86\xF7\x0D\x01\x09"
 #define OID_PKCS9_EMAIL         "\x2A\x86\x48\x86\xF7\x0D\x01\x09\x01"
 
-/*
- * Structures for parsing X.509 certificates
+/** 
+ * @addtogroup x509_module
+ * @{ */
+
+/**
+ * @name Structures for parsing X.509 certificates and CRLs
+ * @{
+ */
+ 
+/** 
+ * Type-length-value structure that allows for ASN1 using DER.
  */
 typedef struct _x509_buf
 {
-    int tag;
-    int len;
-    unsigned char *p;
+    int tag;                /**< ASN1 type, e.g. ASN1_UTF8_STRING. */
+    int len;                /**< ASN1 length, e.g. in octets. */
+    unsigned char *p;       /**< ASN1 data, e.g. in ASCII. */
 }
 x509_buf;
 
+/**
+ * Container for ASN1 named information objects. 
+ * It allows for Relative Distinguished Names (e.g. cn=polarssl,ou=code,etc.).
+ */
 typedef struct _x509_name
 {
-    x509_buf oid;
-    x509_buf val;
-    struct _x509_name *next;
+    x509_buf oid;               /**< The object identifier. */
+    x509_buf val;               /**< The named value. */
+    struct _x509_name *next;    /**< The next named information object. */
 }
 x509_name;
 
+/** Container for date and time (precision in seconds). */
 typedef struct _x509_time
 {
-    int year, mon, day;
-    int hour, min, sec;
+    int year, mon, day;         /**< Date. */
+    int hour, min, sec;         /**< Time. */
 }
 x509_time;
 
+/** 
+ * Container for an X.509 certificate. The certificate may be chained.
+ */
 typedef struct _x509_cert
 {
-    x509_buf raw;
-    x509_buf tbs;
+    x509_buf raw;               /**< The raw certificate data (DER). */
+    x509_buf tbs;               /**< The raw certificate body (DER). The part that is To Be Signed. */
 
-    int version;
-    x509_buf serial;
-    x509_buf sig_oid1;
+    int version;                /**< The X.509 version. (0=v1, 1=v2, 2=v3) */
+    x509_buf serial;            /**< Unique id for certificate issued by a specific CA. */
+    x509_buf sig_oid1;          /**< Signature algorithm, e.g. sha1RSA */
 
-    x509_buf issuer_raw;
-    x509_buf subject_raw;
+    x509_buf issuer_raw;        /**< The raw issuer data (DER). Used for quick comparison. */
+    x509_buf subject_raw;       /**< The raw subject data (DER). Used for quick comparison. */
 
-    x509_name issuer;
-    x509_name subject;
+    x509_name issuer;           /**< The parsed issuer data (named information object). */
+    x509_name subject;          /**< The parsed subject data (named information object). */
 
-    x509_time valid_from;
-    x509_time valid_to;
+    x509_time valid_from;       /**< Start time of certificate validity. */
+    x509_time valid_to;         /**< End time of certificate validity. */
 
-    x509_buf pk_oid;
-    rsa_context rsa;
+    x509_buf pk_oid;            /**< Subject public key info. Includes the public key algorithm and the key itself. */
+    rsa_context rsa;            /**< Container for the RSA context. Only RSA is supported for public keys at this time. */
 
-    x509_buf issuer_id;
-    x509_buf subject_id;
-    x509_buf v3_ext;
+    x509_buf issuer_id;         /**< Optional X.509 v2/v3 issuer unique identifier. */
+    x509_buf subject_id;        /**< Optional X.509 v2/v3 subject unique identifier. */
+    x509_buf v3_ext;            /**< Optional X.509 v3 extensions. Only Basic Contraints are supported at this time. */
 
-    int ca_istrue;
-    int max_pathlen;
+    int ca_istrue;              /**< Optional Basic Constraint extension value: 1 if this certificate belongs to a CA, 0 otherwise. */
+    int max_pathlen;            /**< Optional Basic Constraint extension value: The maximum path length to the root certificate. */
 
-    x509_buf sig_oid2;
-    x509_buf sig;
-    int sig_alg;
+    x509_buf sig_oid2;          /**< Signature algorithm. Must match sig_oid1. */
+    x509_buf sig;               /**< Signature: hash of the tbs part signed with the private key. */
+    int sig_alg;                /**< Internal representation of the signature algorithm, e.g. SIG_RSA_MD2 */
 
-    struct _x509_cert *next; 
+    struct _x509_cert *next;    /**< Next certificate in the CA-chain. */ 
 }
 x509_cert;
 
+/** 
+ * Certificate revocation list entry. 
+ * Contains the CA-specific serial numbers and revocation dates.
+ */
 typedef struct _x509_crl_entry
 {
     x509_buf raw;
@@ -202,22 +248,26 @@
 }
 x509_crl_entry;
 
+/** 
+ * Certificate revocation list structure. 
+ * Every CRL may have multiple entries.
+ */
 typedef struct _x509_crl
 {
-    x509_buf raw;
-    x509_buf tbs;
+    x509_buf raw;           /**< The raw certificate data (DER). */
+    x509_buf tbs;           /**< The raw certificate body (DER). The part that is To Be Signed. */
 
     int version;
     x509_buf sig_oid1;
 
-    x509_buf issuer_raw;
+    x509_buf issuer_raw;    /**< The raw issuer data (DER). */
 
-    x509_name issuer;
+    x509_name issuer;       /**< The parsed issuer data (named information object). */
 
-    x509_time this_update;
+    x509_time this_update;  
     x509_time next_update;
 
-    x509_crl_entry entry;
+    x509_crl_entry entry;   /**< The CRL entries containing the certificate revocation times for this CA. */
 
     x509_buf crl_ext;
 
@@ -228,10 +278,16 @@
     struct _x509_crl *next; 
 }
 x509_crl;
+/** @} name Structures for parsing X.509 certificates and CRLs */
+/** @} addtogroup x509_module */
 
-/*
- * Structures for writing X.509 certificates
+/**
+ * @name Structures for writing X.509 certificates.
+ * XvP: commented out as they are not used.
+ * - <tt>typedef struct _x509_node x509_node;</tt>
+ * - <tt>typedef struct _x509_raw x509_raw;</tt>
  */
+/*
 typedef struct _x509_node
 {
     unsigned char *data;
@@ -259,12 +315,19 @@
     x509_node sign;
 }
 x509_raw;
+*/
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /**
+ * @name Functions to read in a certificate, CRL or private RSA key 
+ * @{
+ */
+
+/** @ingroup x509_module */
+/**
  * \brief          Parse one or more certificates and add them
  *                 to the chained list
  *
@@ -276,6 +339,7 @@
  */
 int x509parse_crt( x509_cert *chain, const unsigned char *buf, int buflen );
 
+/** @ingroup x509_module */
 /**
  * \brief          Load one or more certificates and add them
  *                 to the chained list
@@ -287,6 +351,7 @@
  */
 int x509parse_crtfile( x509_cert *chain, const char *path );
 
+/** @ingroup x509_module */
 /**
  * \brief          Parse one or more CRLs and add them
  *                 to the chained list
@@ -299,6 +364,7 @@
  */
 int x509parse_crl( x509_crl *chain, const unsigned char *buf, int buflen );
 
+/** @ingroup x509_module */
 /**
  * \brief          Load one or more CRLs and add them
  *                 to the chained list
@@ -310,6 +376,7 @@
  */
 int x509parse_crlfile( x509_crl *chain, const char *path );
 
+/** @ingroup x509_module */
 /**
  * \brief          Parse a private RSA key
  *
@@ -325,17 +392,21 @@
                    const unsigned char *key, int keylen,
                    const unsigned char *pwd, int pwdlen );
 
+/** @ingroup x509_module */
 /**
  * \brief          Load and parse a private RSA key
  *
  * \param rsa      RSA context to be initialized
  * \param path     filename to read the private key from
- * \param pwd      password to decrypt the file (can be NULL)
+ * \param password password to decrypt the file (can be NULL)
  *
  * \return         0 if successful, or a specific X509 error code
  */
 int x509parse_keyfile( rsa_context *rsa, const char *path,
                        const char *password );
+/** @} name Functions to read in a certificate, CRL or private RSA key */ 
+
+
 
 /**
  * \brief          Store the certificate DN in printable form into buf;
@@ -372,7 +443,7 @@
  * \param buf      Buffer to write to
  * \param size     Maximum size of buffer
  * \param prefix   A line prefix
- * \param crt      The X509 CRL to represent
+ * \param crl      The X509 CRL to represent
  *
  * \return         The amount of data written to the buffer, or -1 in
  *                 case of an error.
@@ -392,6 +463,11 @@
 int x509parse_time_expired( const x509_time *time );
 
 /**
+ * @name Functions to verify a certificate
+ * @{
+ */
+/** @ingroup x509_module */
+/**
  * \brief          Verify the certificate signature
  *
  * \param crt      a certificate to be verified
@@ -416,6 +492,15 @@
                       x509_crl *ca_crl,
                       const char *cn, int *flags );
 
+/** @} name Functions to verify a certificate */
+
+
+
+/**
+ * @name Functions to clear a certificate, CRL or private RSA key 
+ * @{
+ */
+/** @ingroup x509_module */
 /**
  * \brief          Unallocate all certificate data
  *
@@ -423,13 +508,17 @@
  */
 void x509_free( x509_cert *crt );
 
+/** @ingroup x509_module */
 /**
  * \brief          Unallocate all CRL data
  *
- * \param crt      CRL chain to free
+ * \param crl      CRL chain to free
  */
 void x509_crl_free( x509_crl *crl );
 
+/** @} name Functions to clear a certificate, CRL or private RSA key */
+
+
 /**
  * \brief          Checkup routine
  *