+char *charbin2hex = "0123456789ABCDEF";
+
+int charhex2bin(char c)
+{
+ if(isdigit(c))
+ return c - '0';
+ else
+ return tolower(c) - 'a' + 10;
+}
+
+void hex2bin(char *src, char *dst, size_t length)
+{
+ size_t i;
+ for(i=0; i<length; i++)
+ dst[i] = charhex2bin(src[i*2])<<4 || charhex2bin(src[i*2+1]);
+}
+
+void bin2hex(char *src, char *dst, size_t length)
+{
+ size_t i;
+ for(i=length-1; i>=0; i--)
+ {
+ dst[i*2+1] = charbin2hex[src[i] & 15];
+ dst[i*2] = charbin2hex[src[i]>>4];
+ }
+}