diff --git a/library/debug.c b/library/debug.c
new file mode 100644
index 0000000..4862fc4
--- /dev/null
+++ b/library/debug.c
@@ -0,0 +1,202 @@
+/*
+ *  Debugging routines
+ *
+ *  Copyright (C) 2006-2007  Christophe Devine
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "xyssl/config.h"
+
+#if defined(XYSSL_DEBUG_C)
+
+#include "xyssl/debug.h"
+
+#include <stdarg.h>
+#include <stdlib.h>
+
+#if defined _MSC_VER && !defined  snprintf
+#define  snprintf  _snprintf
+#endif
+
+#if defined _MSC_VER && !defined vsnprintf
+#define vsnprintf _vsnprintf
+#endif
+
+char *debug_fmt( const char *format, ... )
+{
+    va_list argp;
+    static char str[512];
+    int maxlen = sizeof( str ) - 1;
+
+    va_start( argp, format );
+    vsnprintf( str, maxlen, format, argp );
+    va_end( argp );
+
+    str[maxlen] = '\0';
+    return( str );
+}
+
+void debug_print_msg( ssl_context *ssl, int level,
+                      char *file, int line, char *text )
+{
+    char str[512];
+    int maxlen = sizeof( str ) - 1;
+
+    if( ssl->f_dbg == NULL )
+        return;
+
+    snprintf( str, maxlen, "%s(%04d): %s\n", file, line, text );
+    str[maxlen] = '\0';
+    ssl->f_dbg( ssl->p_dbg, level, str );
+}
+
+void debug_print_ret( ssl_context *ssl, int level,
+                      char *file, int line, char *text, int ret )
+{
+    char str[512];
+    int maxlen = sizeof( str ) - 1;
+
+    if( ssl->f_dbg == NULL )
+        return;
+
+    snprintf( str, maxlen, "%s(%04d): %s() returned %d (0x%x)\n",
+              file, line, text, ret, ret );
+
+    str[maxlen] = '\0';
+    ssl->f_dbg( ssl->p_dbg, level, str );
+}
+
+void debug_print_buf( ssl_context *ssl, int level,
+                      char *file, int line, char *text,
+                      unsigned char *buf, int len )
+{
+    char str[512];
+    int i, maxlen = sizeof( str ) - 1;
+
+    if( ssl->f_dbg == NULL || len < 0 )
+        return;
+
+    snprintf( str, maxlen, "%s(%04d): dumping '%s' (%d bytes)\n",
+              file, line, text, len );
+
+    str[maxlen] = '\0';
+    ssl->f_dbg( ssl->p_dbg, level, str );
+
+    for( i = 0; i < len; i++ )
+    {
+        if( i >= 4096 )
+            break;
+
+        if( i % 16 == 0 )
+        {
+            if( i > 0 )
+                ssl->f_dbg( ssl->p_dbg, level, "\n" );
+
+            snprintf( str, maxlen, "%s(%04d): %04x: ", file, line, i );
+
+            str[maxlen] = '\0';
+            ssl->f_dbg( ssl->p_dbg, level, str );
+        }
+
+        snprintf( str, maxlen, " %02x", (unsigned int) buf[i] );
+
+        str[maxlen] = '\0';
+        ssl->f_dbg( ssl->p_dbg, level, str );
+    }
+
+    if( len > 0 )
+        ssl->f_dbg( ssl->p_dbg, level, "\n" );
+}
+
+void debug_print_mpi( ssl_context *ssl, int level,
+                      char *file, int line, char *text, mpi *X )
+{
+    char str[512];
+    int i, j, k, n, maxlen = sizeof( str ) - 1;
+
+    if( ssl->f_dbg == NULL || X == NULL )
+        return;
+
+    for( n = X->n - 1; n >= 0; n-- )
+        if( X->p[n] != 0 )
+            break;
+
+    snprintf( str, maxlen, "%s(%04d): value of '%s' (%d bits) is:\n",
+              file, line, text, ((n + 1) * sizeof( t_int )) << 3 );
+
+    str[maxlen] = '\0';
+    ssl->f_dbg( ssl->p_dbg, level, str );
+
+    for( i = n, j = 0; i >= 0; i--, j++ )
+    {
+        if( j % ( 16 / sizeof( t_int ) ) == 0 )
+        {
+            if( j > 0 )
+                ssl->f_dbg( ssl->p_dbg, level, "\n" );
+
+            snprintf( str, maxlen, "%s(%04d): ", file, line );
+
+            str[maxlen] = '\0';
+            ssl->f_dbg( ssl->p_dbg, level, str );
+        }
+
+        for( k = sizeof( t_int ) - 1; k >= 0; k-- )
+        {
+            snprintf( str, maxlen, " %02x", (unsigned int)
+                      ( X->p[i] >> (k << 3) ) & 0xFF );
+
+            str[maxlen] = '\0';
+            ssl->f_dbg( ssl->p_dbg, level, str );
+        }
+    }
+
+    ssl->f_dbg( ssl->p_dbg, level, "\n" );
+}
+
+void debug_print_crt( ssl_context *ssl, int level,
+                      char *file, int line, char *text, x509_cert *crt )
+{
+    char str[512], prefix[64], *p;
+    int i = 0, maxlen = sizeof( prefix ) - 1;
+
+    if( ssl->f_dbg == NULL || crt == NULL )
+        return;
+
+    snprintf( prefix, maxlen, "%s(%04d): ", file, line );
+    prefix[maxlen] = '\0';
+    maxlen = sizeof( str ) - 1;
+
+    while( crt != NULL && crt->next != NULL )
+    {
+        p = x509parse_cert_info( prefix, crt );
+
+        snprintf( str, maxlen, "%s(%04d): %s #%d:\n%s",
+                  file, line, text, ++i, p );
+
+        str[maxlen] = '\0';
+        ssl->f_dbg( ssl->p_dbg, level, str );
+
+        debug_print_mpi( ssl, level, file, line,
+                         "crt->rsa.N", &crt->rsa.N );
+
+        debug_print_mpi( ssl, level, file, line,
+                         "crt->rsa.E", &crt->rsa.E );
+
+        crt = crt->next;
+    }
+}
+
+#endif