var coinImgUrl = "https://bitcoinpaperwallet.com/bitcoinpaperwallet/images/logo-" + whichDesign + ".png";
...
        var base64 = "data:image/png;base64," + btoa([].reduce.call(new Uint8Array(this.response),function(p,c){return p+String.fromCharCode(c)},''));
                for(var i = 0; i < base64.length; i++)
                {
                    if(i+3 < base64.length)
                    {
                        if(base64.charCodeAt(i) != 0 && base64.charCodeAt(i+1) != 0 && base64.charCodeAt(i+2) != 0 && base64.charCodeAt(i) != 1 && base64.charCodeAt(i+1) != 1 && base64.charCodeAt(i+2) != 1)
                        {
                            SecureRandom.seedInt((base64.charCodeAt(i) * base64.charCodeAt(i+1) * base64.charCodeAt(i+2))*(i+1));
                        }
                    }
                }
                SecureRandom.loaded = 1;
            };