base64 - encode / decode

JavaScript로 Base64에서 문자열을 인코딩하고 디코딩.

안전한 암호화 방법이 될 수는 없지만 따옴표나 글자를 깨뜨릴 필요없이 

웹 페이지 또는 쿠키 파일에 난독화 문자열을 쓰는 데 매우 유용.

ie10 or 모던 브라우저

// Define the string

var string = 'Hello World!';

// Encode the String

var encodedString = btoa(string);

console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"

// Decode the String

var decodedString = atob(encodedString);

console.log(decodedString); // Outputs: "Hello World!"

cross-browser method ( Base64는 압축된 상태 )

// Create Base64 Object

var Base64={_keyStr:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",encode:function(e){var t="";var n,r,i,s,o,u,a;var f=0;e=Base64._utf8_encode(e);while(f<e.length){n=e.charCodeAt(f++);r=e.charCodeAt(f++);i=e.charCodeAt(f++);s=n>>2;o=(n&3)<<4|r>>4;u=(r&15)<<2|i>>6;a=i&63;if(isNaN(r)){u=a=64}else if(isNaN(i)){a=64}t=t+this._keyStr.charAt(s)+this._keyStr.charAt(o)+this._keyStr.charAt(u)+this._keyStr.charAt(a)}return t},decode:function(e){var t="";var n,r,i;var s,o,u,a;var f=0;e=e.replace(/[^A-Za-z0-9+/=]/g,"");while(f<e.length){s=this._keyStr.indexOf(e.charAt(f++));o=this._keyStr.indexOf(e.charAt(f++));u=this._keyStr.indexOf(e.charAt(f++));a=this._keyStr.indexOf(e.charAt(f++));n=s<<2|o>>4;r=(o&15)<<4|u>>2;i=(u&3)<<6|a;t=t+String.fromCharCode(n);if(u!=64){t=t+String.fromCharCode(r)}if(a!=64){t=t+String.fromCharCode(i)}}t=Base64._utf8_decode(t);return t},_utf8_encode:function(e){e=e.replace(/rn/g,"n");var t="";for(var n=0;n<e.length;n++){var r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r)}else if(r>127&&r<2048){t+=String.fromCharCode(r>>6|192);t+=String.fromCharCode(r&63|128)}else{t+=String.fromCharCode(r>>12|224);t+=String.fromCharCode(r>>6&63|128);t+=String.fromCharCode(r&63|128)}}return t},_utf8_decode:function(e){var t="";var n=0;var r=c1=c2=0;while(n<e.length){r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r);n++}else if(r>191&&r<224){c2=e.charCodeAt(n+1);t+=String.fromCharCode((r&31)<<6|c2&63);n+=2}else{c2=e.charCodeAt(n+1);c3=e.charCodeAt(n+2);t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);n+=3}}return t}}

// Define the string

var string = 'Hello World!';

// Encode the String

var encodedString = Base64.encode(string);

console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"

// Decode the String

var decodedString = Base64.decode(encodedString);

console.log(decodedString); // Outputs: "Hello World!"

출처: https://scotch.io/tutorials/how-to-encode-and-decode-strings-with-base64-in-javascript