this.key=(k.length>(keySizeInBitsBlow/4))?k.substr(0,(keySizeInBitsBlow/4)):k;//prima il limite era 56
var j=0;
for(var i=0;i<18;++i){
var d=((this.key.charCodeAt(j%this.key.length)*256+this.key.charCodeAt((j+1)%this.key.length))*256+this.key.charCodeAt((j+2)%this.key.length))*256+this.key.charCodeAt((j+3)%this.key.length);