关于base64加密的用途，在php文档中的描述是：设计此种编码是为了使二进制数据可以通过非纯 8-bit 的传输层传输，例如电子邮件的主体。Base64-encoded 数据要比原始数据多占用 33% 左右的空间。（http://php.net/manual/zh/function.base64-encode.php）
其实base64加密方法的应用远远不止于此，今天就跟大家扒一扒base64加密的几种应用场景。
加密url
相信几乎没有哪个小伙伴没有用过迅雷下载吧，下面就是一个典型的迅雷资源链接：
thunder://QUFlZDJrOi8vfGZpbGV8xM+3vbmr1LAuU291dGguUGFyay5TMTlFMDIu1tDTotfWxLsuSERUVnJpcC4xMDI0WDU3Ni5tcDR8MjIxMzQ0NzUwfDBhYTc3NjdkNWU1NTZiZjM0ZDBjOTcyYWNmMmFhMDU3fGg9Z2YyeGtta2Qya2pvYXF6ZndremU2amFxa2pncXBsZ3h8L1pa上面的链接我们去掉thunder://头，用base64方法解密出来，看看能得到什么结果：
<?php
echo base64_decode('QUFlZDJrOi8vfGZpbGV8xM+3vbmr1LAuU291dGguUGFyay5TMTlFMDIu1tDTotfWxLsuSERUVnJpcC4xMDI0WDU3Ni5tcDR8MjIxMzQ0NzUwfDBhYTc3NjdkNWU1NTZiZjM0ZDBjOTcyYWNmMmFhMDU3fGg9Z2YyeGtta2Qya2pvYXF6ZndremU2amFxa2pncXBsZ3h8L1pa');执行结果如下：
可以看出，迅雷下载专用链接，不过是将ed2k地址字符串前面加上”AA”，结尾加上“ZZ”，再进行了base64加密而已。其他的如快车、qq旋风的下载链接也类似，可自行搜索它们的加密方法，这里不再赘述。
传输二进制数据，如邮件主题及图片等
这个应用场景就是php文档中提到的用途，这里以图片为例。
<?php
echo base64_encode(file_get_contents('https://www.baidu.com/img/bd_logo1.png'));执行结果如下：
iVBORw0KGgoAAAANSUhEUgAAAhwAAAECCAMAAACCFP44AAAACXBIWXMAAAsTAAALEwEAmpwYAAAKTWlDQ1BQaG90b3Nob3AgSUNDIHByb2ZpbGUAAHjanVN3WJP3Fj7f92UPVkLY8LGXbIEAIiOsCMgQWaIQkgBhhBASQMWFiApWFBURnEhVxILVCkidiOKgKLhnQYqIWotVXDjuH9yntX167+3t+9f7vOec5/zOec8PgBESJpHmomoAOVKFPDrYH49PSMTJvYACFUjgBCAQ5svCZwXFAADwA3l4fnSwP/wBr28AAgBw1S4kEsfh/4O6UCZXACCRAOAiEucLAZBSAMguVMgUAMgYALBTs2QKAJQAAGx5fEIiAKoNAOz0ST4FANipk9wXANiiHKkIAI0BAJkoRyQCQLsAYFWBUiwCwMIAoKxAIi4EwK4BgFm2MkcCgL0FAHaOWJAPQGAAgJlCLMwAIDgCAEMeE80DIEwDoDDSv+CpX3CFuEgBAMDLlc2XS9IzFLiV0Bp38vDg4iHiwmyxQmEXKRBmCeQinJebIxNI5wNMzgwAABr50cH+OD+Q5+bk4eZm52zv9MWi/mvwbyI+IfHf/ryMAgQAEE7P79pf5eXWA3DHAbB1v2upWwDaVgBo3/ldM9sJoFoK0Hr5i3k4/EAenqFQyDwdHAoLC+0lYqG9MOOLPv8z4W/gi372/EAe/tt68ABxmkCZrcCjg/1xYW52rlKO58sEQjFu9+cj/seFf/2OKdHiNLFcLBWK8ViJuFAiTcd5uVKRRCHJleIS6X8y8R+W/QmTdw0ArIZPwE62B7XLbMB+7gECiw5Y0nYAQH7zLYwaC5EAEGc0Mnn3AACTv/mPQCsBAM2XpOMAALzoGFyolBdMxggAAESggSqwQQcMwRSswA6cwR28wBcCYQZEQAwkwDwQQgbkgBwKoRiWQRlUwDrYBLWwAxqgEZrhELTBMTgN5+ASXIHrcBcGYBiewhi8hgkEQcgIE2EhOogRYo7YIs4IF5mOBCJhSDSSgKQg6YgUUSLFyHKkAqlCapFdSCPyLXIUOY1cQPqQ28ggMor8irxHMZSBslED1AJ1QLmoHxqKxqBz0XQ0D12AlqJr0Rq0Hj2AtqKn0UvodXQAfYqOY4DRMQ5mjNlhXIyHRWCJWBomxxZj5Vg1Vo81Yx1YN3YVG8CeYe8IJAKLgBPsCF6EEMJsgpCQR1hMWEOoJewjtBK6CFcJg4Qxwicik6hPtCV6EvnEeGI6sZBYRqwm7iEeIZ4lXicOE1+TSCQOyZLkTgohJZAySQtJa0jbSC2kU6Q+0hBpnEwm65Btyd7kCLKArCCXkbeQD5BPkvvJw+S3FDrFiOJMCaIkUqSUEko1ZT/lBKWfMkKZoKpRzame1AiqiDqfWkltoHZQL1OHqRM0dZolzZsWQ8ukLaPV0JppZ2n3aC/pdLoJ3YMeRZfQl9Jr6Afp5+mD9HcMDYYNg8dIYigZaxl7GacYtxkvmUymBdOXmchUMNcyG5lnmA+Yb1VYKvYqfBWRyhKVOpVWlX6V56pUVXNVP9V5qgtUq1UPq15WfaZGVbNQ46kJ1Bar1akdVbupNq7OUndSj1DPUV+jvl/9gvpjDbKGhUaghkijVGO3xhmNIRbGMmXxWELWclYD6yxrmE1iW7L57Ex2Bfsbdi97TFNDc6pmrGaRZp3mcc0BDsax4PA52ZxKziHODc57LQMtPy2x1mqtZq1+rTfaetq+2mLtcu0W7eva73VwnUCdLJ31Om0693UJuja6UbqFutt1z+o+02PreekJ9cr1Dund0Uf1bfSj9Rfq79bv0R83MDQINpAZbDE4Y/DMkGPoa5hpuNHwhOGoEctoupHEaKPRSaMnuCbuh2fjNXgXPmasbxxirDTeZdxrPGFiaTLbpMSkxeS+Kc2Ua5pmutG003TMzMgs3KzYrMnsjjnVnGueYb7ZvNv8jYWlRZzFSos2i8eW2pZ8ywWWTZb3rJhWPlZ5VvVW16xJ1lzrLOtt1ldsUBtXmwybOpvLtqitm63Edptt3xTiFI8p0in1U27aMez87ArsmuwG7Tn2YfYl9m32zx3MHBId1jt0O3xydHXMdmxwvOuk4TTDqcSpw+lXZxtnoXOd8zUXpkuQyxKXdpcXU22niqdun3rLleUa7rrStdP1o5u7m9yt2W3U3cw9xX2r+00umxvJXcM970H08PdY4nHM452nm6fC85DnL152Xlle+70eT7OcJp7WMG3I28Rb4L3Le2A6Pj1l+s7pAz7GPgKfep+Hvqa+It89viN+1n6Zfgf8nvs7+sv9j/i/4XnyFvFOBWABwQHlAb2BGoGzA2sDHwSZBKUHNQWNBbsGLww+FUIMCQ1ZH3KTb8AX8hv5YzPcZyya0RXKCJ0VWhv6MMwmTB7WEY6GzwjfEH5vpvlM6cy2CIjgR2yIuB9pGZkX+X0UKSoyqi7qUbRTdHF09yzWrORZ+2e9jvGPqYy5O9tqtnJ2Z6xqbFJsY+ybuIC4qriBeIf4RfGXEnQTJAntieTE2MQ9ieNzAudsmjOc5JpUlnRjruXcorkX5unOy553PFk1WZB8OIWYEpeyP+WDIEJQLxhP5aduTR0T8oSbhU9FvqKNolGxt7hKPJLmnVaV9jjdO31D+miGT0Z1xjMJT1IreZEZkrkj801WRNberM/ZcdktOZSclJyjUg1plrQr1zC3KLdPZisrkw3keeZtyhuTh8r35CP5c/PbFWyFTNGjtFKuUA4WTC+oK3hbGFt4uEi9SFrUM99m/ur5IwuCFny9kLBQuLCz2Lh4WfHgIr9FuxYji1MXdy4xXVK6ZHhp8NJ9y2jLspb9UOJYUlXyannc8o5Sg9KlpUMrglc0lamUycturvRauWMVYZVkVe9ql9VbVn8qF5VfrHCsqK74sEa45uJXTl/VfPV5bdra3kq3yu3rSOuk626s91m/r0q9akHV0IbwDa0b8Y3lG19tSt50oXpq9Y7NtM3KzQM1YTXtW8y2rNvyoTaj9nqdf13LVv2tq7e+2Sba1r/dd3vzDoMdFTve75TsvLUreFdrvUV99W7S7oLdjxpiG7q/5n7duEd3T8Wej3ulewf2Re/ranRvbNyvv7+yCW1SNo0eSDpw5ZuAb9qb7Zp3tXBaKg7CQeXBJ9+mfHvjUOihzsPcw83fmX+39QjrSHkr0jq/dawto22gPaG97+iMo50dXh1Hvrf/fu8x42N1xzWPV56gnSg98fnkgpPjp2Snnp1OPz3Umdx590z8mWtdUV29Z0PPnj8XdO5Mt1/3yfPe549d8Lxw9CL3Ytslt0utPa49R35w/eFIr1tv62X3y+1XPK509E3rO9Hv03/6asDVc9f41y5dn3m978bsG7duJt0cuCW69fh29u0XdwruTNxdeo94r/y+2v3qB/oP6n+0/rFlwG3g+GDAYM/DWQ/vDgmHnv6U/9OH4dJHzEfVI0YjjY+dHx8bDRq98mTOk+GnsqcTz8p+Vv9563Or59/94vtLz1j82PAL+YvPv655qfNy76uprzrHI8cfvM55PfGm/K3O233vuO+638e9H5ko/ED+UPPR+mPHp9BP9z7nfP78L/eE8/sl0p8zAAAAIGNIUk0AAHolAACAgwAA+f8AAIDpAAB1MAAA6mAAADqYAAAXb5JfxUYAAAMAUExURQAAAP///+EGASMZ3Pz7/vX0/fb1/fLx/fPy/fTz/TIo3kY94UxD4l9X5XJr6Hdw6Xhx6YR+64uF7JqV75uW75yX752Y76Sf8K+r8rGt87ay88fE9snG9s/M99DN99bU+NjW+drY+dza+eLg+uvq/Ozr/O3s/O7t/O/u/CQa3CYc3Cce3Sge3Ssh3Swi3Swj3i0k3i4l3i8m3jAn3jMq3zQr3zUs3zYt3zcu3zgv3zkw4Dkw3zox4Dsy4Dwz4D004D414D834UA44UI54UM64UQ74UU84UY+4khA4kpC4k1F409H41JK41JL5FNM5FZO5FlR5VtU5VxV5V9Y5mFa5mNc5mRd5mVe52Zf52dg52hh52li52pj52tl6G5n6G9o6HNt6XRu6Xlz6nt16n136n546n9664F764J864R/7IaB7IiD7IuG7Y2I7Y+K7ZGM7pCL7ZKN7pGM7ZOO7pSP7paR7piU75+b8KCc8KSg8aej8aik8auo8rKv87Sx87e09Lm29Lu49Ly59L+89cG+9cPB9sXD9svJ983L99DO+NPR+NTS+N7d+uDf+uPi++Tj++Xk++bl++fm++no/Ojn++rp/Ono+/Dw/fb2/vn5/vr6/vz8//7+//zo5/3r6uMTDuMUD+MVEOMWEeMXEuMYE+MaFfCFgvGHhPGJhvGOi/KRjvKUkfKWk/Shn/SmpPWpp/WsqvWurPa0sve5t/e6uPe9u/e/vffBv/rT0vrU0/rW1frY1/va2fvc2/vd3Pvg3/zj4vvi4fzl5Pzn5uEHAuEIA+EJBOEKBeILBuIMB+INCOIPCuIQC+QbF+QdGeQfG+QgHOUjH+UlIeUpJeUqJuYtKeYvK+YzL+c2Muc5Nec8OOg+OuhAPOlEQelGQ+lIRelKR+lMSepPTOtWU+tZVuteW+xiX+1mY+1qZ+1tau5wbu92dO99e/B/ffCAfvCCgPOZl/OenPjBwPjEw/jGxfnJyPnMy/nPzv3u7v3w8P719f729v75+f/7+//9/f///4DJalUAAAEAdFJOU////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////wBT9wclAAAP2klEQVR42uzdaXwURRoGcKsrJEAIi0G5A4RATEICaBQWMYiEXcGA4Y6yHIICcikKAlkuJYRICCLHLklmhMUgghwiiAguiC6IcsgRORRRdzlFFLwRE377wWRm+qjq7pnumeme5/mYeaeH6frT3dNVXXUTQRBGbsIuQIADAQ4EOBDgQIADAQ4EOBDgQIADAQ4EAQ4EOBDgQIADAQ4EOBDgQIADAQ4EOBAEOBDgQIADAQ4EOBDgQIADAQ4EOBDgQBDgQIADAQ4EOBDgQIADAQ4EOBDgQIADAQ4EAQ4EOBDgQIADAQ4EOBDgQIADAQ4EOBAEOBDgQIADAQ4EOBDgQIADAQ4EOBDgQBDgQIADAQ4EOBDgQIADAQ4EOBDgQIADAQ4EAQ4EOBDgQIADAQ4EOBDgQIADAQ4EOBAEOBDgQIADAQ4EOBDgQIADAQ4EOBDgQBDgQIADAQ4EOHzP0uyH7klO6TSofiEIAIcohU+0oRVpN8UBBMDhTuz91COZ/4QC4KhMo1QqSscCHqTJjw0Zk1MEHKGRxq2oJGmLWLUNe/5R0XZ8VeAIgcSnUVkylI8MCYPdJe1mAof98xBVyGilyvx7RDVjncBh88xUskGT5skrZ7eWFA0uBg5bJ6yLIg4aJavMSZYVPeQADjunHmUkRvWylVI6CjjsnO4sHDXFdYs7KFY9Bxz2TSzLBk2p5lnn6Klc1S4BOGybp5k4aH3PultYVcOBw7Z5kI3jEY+yuBRWVVIccNg0VZLYODp61A1gl40ADpsmj3IS7yqL4VTdEQ4c9kw2D0dDV9lAXlkD4LBnonmtPs31MzaJV/Yn4LBnhvJafUJl1TO8KpoOHPZMFq/VoyurunJxJBYBhy3Tl9fqlb9DFlN+CoDDlunPa/SbK4pmq+CYBxy2zEAtp5VsFRxNgcOWGcZr9Fsrip5UwbEIOGwZbrtPrygazbdxuwM4bJl6vFZvXFE0nI8jCj9l7ZmmvJ+oVSqKRvBxjAcOeyasNbvRa1QWRfNxzAGO0LvR4RoCyL9BemcxcNg02RqOCH/n4gip0T6hhSOe2afW3vUjZA4XRxPgsH4i6g3vmd6t96gc8WlgMKvRx7lKWvBs9CfAYfVUG+16suCuJyM8XmAN90le6K6J5OCYCxxWT97dng3aoYH6Jann6D/Oz5UsAhwWT33pw2qPuc8tsclKjX5XvMfbG7OfXygADotnlvyqs597dqenVZ9LIA+wcEwiwGHtvJCq0Kx9XccOR2/5q8PEW5jJsNEHz8paPE7lh9UedRUs7caWU5F+ygMEIwhwWPyCQ238MImXPDA7QDajYHOFCV7ofS8Q4LB2wu5jdbW7x2EUDk90/73lBIWTRew98r6XFwlwWDzsXvlBHlUxURU8Wg6KVdzMwkzpEwnhBDisnkx2n3xjz7oF2Y8+PHDEtBas7Timep5aMnI9XirOublX2u00uVNUdCMHcFgnzTh3Nx/WtynHrGHpiZRS2nlYQ4/pwAqfauexzU51i4DDKnmKN5xnoe7Nhc/PL1gq+ksT6bxR6Y2AwyLpzus1q+P79nPkkzMk1gEOSyQhkYejr8/bz1eaKYyOBQ4rZBZ3LMbdvm6+MF15w1OAwwLhP3OSGGbSFU1yY+AI/gzkDw5e7NvWI9qwNty1GDiCPt34OGJ923od9panAEfQpxUfR75vW3+AveX2RcAR5Kmi8phrnk9bX8DbdD3gCPJEmIpjGm/TvYAjyBNOzTytPMbbdNJtwBHkacPH0YzxtkXTRkRFdu7SPWvsLM5qkZk01GYZtBcO/nReVHEtrqpTPO+5pwxh9pV04G57NHAEeQZz26+6wjsKJ94hLesZo7jtMO6teToQOII8t3DbL0P+hhlKh4PEEUojexbyj0qZwBHkmcdtv2GyMwprYtLIWPm2m/BxdAOOII8zTc+9iIK/MEtTc2XbzgsuHIJngENLRvF+bTaXHAru4hQnz5Jueg5wWDzNOFeNvcWl89tyGztZeuzI4ePoChycfyAzyw+fOnt5039M3Tuu/cOZwXqG6O3x6Sp3zFrNw2nFfBwVOXJxc7n5OOYxDx2RotEczj5ULWkt9ODoARw+4BAE4fCVZWbjILVYrSe+iMim6ukjWoN6rkqxd7tEKcS4Tfnmxq84BGH5q7+bjKNqZ+XGGyq+adFGAw5aW/Tbhl9bCzh8xSEIx34xFwdjEHAPcafJAC02aIpnZ0yEpvlJgcMXHMK+DebiUHp8gHYXLwjbgGpLhufwv1Sq4SYKcPiEQ9i93lwcJK+d7JhfRfTWxdU14hBNB/WglsUUgMM3HMIHm8zFQZqLBxrXmC1+pyOKas5M99u4k6Lf6QAOQ3AIK18yFwchMTUrzy1/HtrQKXnnRO02aGqctnNRTQIcxuAQzpqNg5DC57PHj6vdINYpe2NOkg4cHpcd1XjDl58DDqNwCD+ZjoOZpqlUV9wTRnEWl7w3DDgMw3EmYDgWpVGdcc0h2Ix9yJlKTMURoJ6qAOH48FqAcER002uDJrrurY5klTygaRKXH0T/4OM6viDR6MVgTwHCIWwIzP+Fwl5Uf1pVPgpbyHisKbWZpg8/LdoDV0ILB6vs+rb1Z/ZKai8GxkYU9SZtF1R25WYo4mlI9B84hG3AUZlfPxHXngoKG+6XVAZrVE5/HV5TYQ5KjY/DnNZ3VgkhHGTZIVHtwQDYqCo7p2jFQTNcE9Q2jBIPCmg1rirx5sBxRR8Oy/9a4RevEtXu8b+NFvJzgmYcNNPdcVfwTJ/KXzzV+03VPK2x+MAhbAcOj7whLv5N41Xt7ldOXLj6vgE24hSGE2vHQXuLnqOv1mxubqMmzQ2+ShfvxVDC8ZZ3OP7ojflyi68/Zee2pz7hoFnFXu0U4NDy75Ccc8t17swvdvqEI1dx1VA9OOiAYuAwC8dGcd+b7p15YL0PH95AcQ0efThovyLgMAnHd6Lak17szO+8/vBsxo1vfThoVCFwmIPjhKj2vDc781vvPrz4cVZr68RBe1YBDjNwbBLXrvVqZ1715sOXsIdw6cVBeyQECIetb4Jtf0Vc+45XO/Ojn/V/eKN21DgcNHIBcBiNY+PL4tJSL3fmJ7/r/fCpLamROGjHWOAwEsf7609J98Aab3fmZZ0f/oT0aYPBMxYp1Wnvhav+PHAY8KtteUlJSUlJyQqFV655uzP37dKDwymZ5C11IuuagX0ckf01pYHmneLNjgwRHFp/lLLz729XSt96SQcOp2TA+BDmwkx6cNDESUGKY4sdcBy7rvkjrl2QvHf/S9pxiBceT57G+Rw9OCitVRyMOLYftgGOFdv0fMgqybtXa8aRrWNIjj4cNLNFoHGYeX8jgDgOvKXvU/4nKI6SUd0ZeS25k7H4hIN2igUOE3Ac/lnnp/ygaeS+7G233S06cEwmhuKgbZsGNY5SK+LYc0H3FB3XvcMxRNcSXrpx0E7xwYzjVSvi2Ht+h0G3U1RwiFf0SokzHAft5QheHKXXrXla2beqzA84isVTfo1yv1Ll1q6MhteJg7HaZDDg+OQdYk0cgvD5MvNx1BXPMrnE9cLsDsyG14ujzZKgxLHvxOrfiGVxCEe2mY3DIZ78qZ/rhdyW1DAcHo/R+gmHnxOYO6SvSC88yjaeOej9o6Ty/fecuBWnu+6ZdqEG4khe4ue+lZDAIZSKnpW98f0R/XuPi2MAY+W/fGokDsXlhoHD5/1wzmMzy77yZu/xcBRKJgt0rYIwwVgcnRx+wxGAgWD+Gc+x7Vv5OeNN16tvfywYjUMyFXWK64W+xuJQWhjMJBwf2hUHIWWrpF/uROVLOw8LhuOYwFqFp7PBOCb6DccK++IgZMsBSfXWim7XUsF4HIMks7m5XqhuMI7+wGEEDvK6pLpi/Pk5wQQcNSQ3JFwvtDcYx71+w/GyrXGQL8XVB28QQshWwQwcHSnjgjTTYBxJYf7CccTeOKSHju2EEPKZKThuZy1i/7TBOOiSoMZRuskqOKRd768TQn4STMHRmrXUyvxEg3EU+AvHUf1b2u/rKgR+xPGLpHwdIeS8pM/2m3cNuX0uXfNxJKMj33ccsf66fb5DMuZJ+K90ho83JTOAnH0vmG6CqVRvlg85KFuhZYyYfhyRkiZMd72yOE0LjjTNOF70X9/K5uOS/0kXPFa/uvHGp5IBc1uC6w6pSvWrkvJVsjk7NhjV8ZbFvlkVm64BR7RmHBF+7HgrXyP5yeJavaZ8gwTOv9YYsSqWH3GclONYK+7KN6xXNlrahsPdr4VPykhRw1E8uq02HMlOv/bKLru4R9K//f0NQsquSi5Idp83ZkW9gE37JAhrCfla+geDcNSXLauzROWrUErpIg01ktzv7y77XyUXFsLJza9Jux9O/kSItXDsOiTFsYmQs1rOKl7geFHWio9oaPi6+nEM8v94jtdVftSuXHeDWAzHj/Kv9K70qYNVhuEg6arLUSs0fHqRbhy1/Y+D/L5qP2cA90UD11j0C473Nyh0yh8khJwR/eVYuWE4RqsvIqzQ8GN044gJAA5C3ju3m2Hj1K+EBCcOfTlPCLko/tOlcqNwKKzzmTJdteETJ+vEkeoICA5CfjyptEs/Xk+IPXC8RQhZJx16vNUgHM5IpdU9E1QbfkSxLhw1SYBwkBvfS2eTF3ZfukZsguM4IYTs3G3O7XNCpiguxPbEP9QaPn26UweO2cbg+FE/jmVn5Tvm5MYym+DYSAgh5HOzcIS3VZx5Jflv2fNVGr7LuFitODo4DMGx87heHLsur1QeuP31ppdsgONLxs0Po3CQOtT8jDH8XKsFx461X+21Xpe9nmcTKmYzv3HSLBxFkabbSF7oPxw+b806OA64nrT/5SOTcJC8JLNxPEqAw3gcyz16X6+ahUPX8rHe5M4EM3Ac0I3j9Gk74TghGonwjVk4nIPNxTGDmIHjM504Tv9Ayq/stwuOvd9Ixiet3mMODlKcZaaNm4kpONbownH6jxtDO87ttQOOfRfk83NsOWoODlI81DwbtRym4Dh6XTuOD866J0l69/Ihi+P46It1ijfxrq8+aAoOQrJbm0MjcYzTlNvGh98mWnEcurxLfM/058uffmBFHAcOHvviwmtb2dPNlG26VGoGDhL3cKLauqBRw2tPz80viIubn5/3bN1RWX9tqWqj3bO6d8r+EtUc+XzNb0QbjqNfbzFiqJeZOCyR/EdSmCvQ9x8/S2EUUHHjyQPa8O5vjEwgIZGbQuA7hs98vPe9d3j0pXbOyBp5a4O5vDU/i3KjeyjfKEkbu4QQ4LBXwpYujYuLi0tY6tT6jmpzag+uITrspPZ7JsYRMnsshHB4GefiJjnT/l5nUt2pz86ND7HvDhwIcCDAgQAHAhwIcCDAgQAHAhwIcCDAgSDAgQAHAhwIcCDAgQAHAhwIcCDAgQAHggAHAhwIcCDAgfg1/x8Ate1CIJg9Qs4AAAAASUVORK5CYII=得到了加密后的字符串后如何在网页上展示呢？根据图片的格式可以使用如下格式来显示图片（其实这种展示方式源自Data URI scheme，感兴趣的可以自行搜索）
- data:image/gif;base64，base64 编码的 gif 图片数据
- data:image/png;base64，base64 编码的 png 图片数据
data:image/jpeg;base64，base64 编码的 jpeg 图片数据
就上面的png图片而言，在html中我们可以这样显示：
<img src="data:image/png;base64,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" />这样就能正常显示图片了（恩，百度是世界上最好用的搜索引擎，没有之一）：
在css中我可以这样显示：
background-image: 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);
对于不支持DataURI ，我们可以通过php的base64_decode方法，再使用file_put_contents方法将解密后的数据保存成图片即可。这里不再举例。
对图片进行 base64 编码后，图片能随 HTML 一起传输到浏览器，可以减少 HTTP 请求，也有不少缺点（这部分优点机缺点的概括来自网上的博文：http://liming.it/blog/2014/04/08/image-base64-encode-and-decode-using-php/）：
- IE7 及以前的版本不支持 DataURI 格式。 IE8 开始虽然支持，但限制大小不可超过 32KB。
- 高清图片产生的 DataURI 字符串大得惊人(比原本的图片还大约 1/3)。（这一点可以从上面的加密结果中看出来）
- 图片修改后必须要重新编码，嵌入这个图片的 HTML 也必须修改，不利于浏览器缓存。
- 如果 HTML 中相同图片很多，没法复用。
加密cookie
在笔者待过的几家公司中，都使用了base64的方式来解密一些如用户名之类对安全性要求不高的cookie数据。具体的用法见后续文章（后续笔者将写一篇与cookie相关的博文，里面会用到base64加密cookie，敬请期待）。