| 1 | Website
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| 2 | ======================
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| 3 | http://travistidwell.com/jsencrypt
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| 4 |
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| 5 | Introduction
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| 6 | ======================
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| 7 | When browsing the internet looking for a good solution to RSA Javascript
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| 8 | encryption, there is a whole slew of libraries that basically take the fantastic
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| 9 | work done by Tom Wu @ http://www-cs-students.stanford.edu/~tjw/jsbn/ and then
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| 10 | modify that code to do what they want.
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| 11 |
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| 12 | What I couldn't find, however, was a simple wrapper around this library that
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| 13 | basically uses the library <a href="https://github.com/travist/jsencrypt/pull/6">practically</a> untouched, but adds a wrapper to provide parsing of
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| 14 | actual Private and Public key-pairs generated with OpenSSL.
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| 15 |
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| 16 | This library is the result of these efforts.
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| 17 |
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| 18 | How to use this library.
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| 19 | =======================
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| 20 | This library should work hand-in-hand with openssl. With that said, here is how to use this library.
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| 21 |
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| 22 | - Within your terminal (Unix based OS) type the following.
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| 23 |
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| 24 | ```
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| 25 | openssl genrsa -out rsa_1024_priv.pem 1024
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| 26 | ```
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| 27 |
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| 28 | - This generates a private key, which you can see by doing the following...
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| 29 |
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| 30 | ```
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| 31 | cat rsa_1024_priv.pem
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| 32 | ```
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| 33 |
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| 34 | - You can then copy and paste this in the Private Key section of within index.html.
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| 35 | - Next, you can then get the public key by executing the following command.
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| 36 |
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| 37 | ```
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| 38 | openssl rsa -pubout -in rsa_1024_priv.pem -out rsa_1024_pub.pem
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| 39 | ```
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| 40 |
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| 41 | - You can see the public key by typing...
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| 42 |
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| 43 | ```
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| 44 | cat rsa_1024_pub.pem
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| 45 | ```
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| 46 |
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| 47 | - Now copy and paste this in the Public key within the index.html.
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| 48 | - Now you can then convert to and from encrypted text by doing the following in code.
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| 49 |
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| 50 |
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| 51 | ```html
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| 52 | <!doctype html>
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| 53 | <html>
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| 54 | <head>
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| 55 | <title>JavaScript RSA Encryption</title>
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| 56 | <script src="http://code.jquery.com/jquery-1.8.3.min.js"></script>
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| 57 | <script src="bin/jsencrypt.min.js"></script>
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| 58 | <script type="text/javascript">
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| 59 |
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| 60 | // Call this code when the page is done loading.
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| 61 | $(function() {
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| 62 |
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| 63 | // Run a quick encryption/decryption when they click.
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| 64 | $('#testme').click(function() {
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| 65 |
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| 66 | // Encrypt with the public key...
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| 67 | var encrypt = new JSEncrypt();
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| 68 | encrypt.setPublicKey($('#pubkey').val());
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| 69 | var encrypted = encrypt.encrypt($('#input').val());
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| 70 |
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| 71 | // Decrypt with the private key...
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| 72 | var decrypt = new JSEncrypt();
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| 73 | decrypt.setPrivateKey($('#privkey').val());
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| 74 | var uncrypted = decrypt.decrypt(encrypted);
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| 75 |
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| 76 | // Now a simple check to see if the round-trip worked.
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| 77 | if (uncrypted == $('#input').val()) {
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| 78 | alert('It works!!!');
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| 79 | }
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| 80 | else {
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| 81 | alert('Something went wrong....');
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| 82 | }
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| 83 | });
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| 84 | });
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| 85 | </script>
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| 86 | </head>
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| 87 | <body>
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| 88 | <label for="privkey">Private Key</label><br/>
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| 89 | <textarea id="privkey" rows="15" cols="65">-----BEGIN RSA PRIVATE KEY-----
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| 90 | MIICXQIBAAKBgQDlOJu6TyygqxfWT7eLtGDwajtNFOb9I5XRb6khyfD1Yt3YiCgQ
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| 91 | WMNW649887VGJiGr/L5i2osbl8C9+WJTeucF+S76xFxdU6jE0NQ+Z+zEdhUTooNR
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| 92 | aY5nZiu5PgDB0ED/ZKBUSLKL7eibMxZtMlUDHjm4gwQco1KRMDSmXSMkDwIDAQAB
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| 93 | AoGAfY9LpnuWK5Bs50UVep5c93SJdUi82u7yMx4iHFMc/Z2hfenfYEzu+57fI4fv
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| 94 | xTQ//5DbzRR/XKb8ulNv6+CHyPF31xk7YOBfkGI8qjLoq06V+FyBfDSwL8KbLyeH
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| 95 | m7KUZnLNQbk8yGLzB3iYKkRHlmUanQGaNMIJziWOkN+N9dECQQD0ONYRNZeuM8zd
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| 96 | 8XJTSdcIX4a3gy3GGCJxOzv16XHxD03GW6UNLmfPwenKu+cdrQeaqEixrCejXdAF
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| 97 | z/7+BSMpAkEA8EaSOeP5Xr3ZrbiKzi6TGMwHMvC7HdJxaBJbVRfApFrE0/mPwmP5
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| 98 | rN7QwjrMY+0+AbXcm8mRQyQ1+IGEembsdwJBAN6az8Rv7QnD/YBvi52POIlRSSIM
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| 99 | V7SwWvSK4WSMnGb1ZBbhgdg57DXaspcwHsFV7hByQ5BvMtIduHcT14ECfcECQATe
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| 100 | aTgjFnqE/lQ22Rk0eGaYO80cc643BXVGafNfd9fcvwBMnk0iGX0XRsOozVt5Azil
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| 101 | psLBYuApa66NcVHJpCECQQDTjI2AQhFc1yRnCU/YgDnSpJVm1nASoRUnU8Jfm3Oz
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| 102 | uku7JUXcVpt08DFSceCEX9unCuMcT72rAQlLpdZir876
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| 103 | -----END RSA PRIVATE KEY-----</textarea><br/>
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| 104 | <label for="pubkey">Public Key</label><br/>
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| 105 | <textarea id="pubkey" rows="15" cols="65">-----BEGIN PUBLIC KEY-----
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| 106 | MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDlOJu6TyygqxfWT7eLtGDwajtN
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| 107 | FOb9I5XRb6khyfD1Yt3YiCgQWMNW649887VGJiGr/L5i2osbl8C9+WJTeucF+S76
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| 108 | xFxdU6jE0NQ+Z+zEdhUTooNRaY5nZiu5PgDB0ED/ZKBUSLKL7eibMxZtMlUDHjm4
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| 109 | gwQco1KRMDSmXSMkDwIDAQAB
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| 110 | -----END PUBLIC KEY-----</textarea><br/>
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| 111 | <label for="input">Text to encrypt:</label><br/>
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| 112 | <textarea id="input" name="input" type="text" rows=4 cols=70>This is a test!</textarea><br/>
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| 113 | <input id="testme" type="button" value="Test Me!!!" /><br/>
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| 114 | </body>
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| 115 | </html>
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| 116 | ```
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| 117 |
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| 118 | - Look at how http://www.travistidwell.com/jsencrypt/demo works to get a better idea.
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| 119 |
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| 120 | - Signing and verification works in a similar way.
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| 121 |
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| 122 | ```javascript
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| 123 | // Sign with the private key...
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| 124 | var sign = new JSEncrypt();
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| 125 | sign.setPrivateKey($('#privkey').val());
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| 126 | var signature = sign.sign($('#input').val(), CryptoJS.SHA256, "sha256");
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| 127 |
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| 128 | // Verify with the public key...
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| 129 | var verify = new JSEncrypt();
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| 130 | verify.setPublicKey($('#pubkey').val());
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| 131 | var verified = verify.verify($('#input').val(), signature, CryptoJS.SHA256);
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| 132 |
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| 133 | // Now a simple check to see if the round-trip worked.
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| 134 | if (verified) {
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| 135 | alert('It works!!!');
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| 136 | }
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| 137 | else {
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| 138 | alert('Something went wrong....');
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| 139 | }
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| 140 | ```
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| 141 |
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| 142 | - Note that you have to provide the hash function. In this example we use one from the [CryptoJS](https://github.com/brix/crypto-js) library, but you can use whichever you want.
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| 143 | - Also, unless you use a custom hash function, you should provide the hash type to the `sign` method. Possible values are: `md2`, `md5`, `sha1`, `sha224`, `sha256`, `sha384`, `sha512`, `ripemd160`.
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| 144 |
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| 145 | Other Information
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| 146 | ========================
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| 147 |
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| 148 | This library heavily utilizes the wonderful work of Tom Wu found at http://www-cs-students.stanford.edu/~tjw/jsbn/.
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| 149 |
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| 150 | This jsbn library was written using the raw variables to perform encryption. This is great for encryption, but most private keys use a Private Key in the PEM format seen below.
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| 151 |
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| 152 | 1024 bit RSA Private Key in Base64 Format
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| 153 | -----------------------------------------
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| 154 | ```
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| 155 | -----BEGIN RSA PRIVATE KEY-----
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| 156 | MIICXgIBAAKBgQDHikastc8+I81zCg/qWW8dMr8mqvXQ3qbPAmu0RjxoZVI47tvs
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| 157 | kYlFAXOf0sPrhO2nUuooJngnHV0639iTTEYG1vckNaW2R6U5QTdQ5Rq5u+uV3pMk
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| 158 | 7w7Vs4n3urQ6jnqt2rTXbC1DNa/PFeAZatbf7ffBBy0IGO0zc128IshYcwIDAQAB
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| 159 | AoGBALTNl2JxTvq4SDW/3VH0fZkQXWH1MM10oeMbB2qO5beWb11FGaOO77nGKfWc
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| 160 | bYgfp5Ogrql4yhBvLAXnxH8bcqqwORtFhlyV68U1y4R+8WxDNh0aevxH8hRS/1X5
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| 161 | 031DJm1JlU0E+vStiktN0tC3ebH5hE+1OxbIHSZ+WOWLYX7JAkEA5uigRgKp8ScG
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| 162 | auUijvdOLZIhHWq7y5Wz+nOHUuDw8P7wOTKU34QJAoWEe771p9Pf/GTA/kr0BQnP
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| 163 | QvWUDxGzJwJBAN05C6krwPeryFKrKtjOGJIniIoY72wRnoNcdEEs3HDRhf48YWFo
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| 164 | riRbZylzzzNFy/gmzT6XJQTfktGqq+FZD9UCQGIJaGrxHJgfmpDuAhMzGsUsYtTr
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| 165 | iRox0D1Iqa7dhE693t5aBG010OF6MLqdZA1CXrn5SRtuVVaCSLZEL/2J5UcCQQDA
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| 166 | d3MXucNnN4NPuS/L9HMYJWD7lPoosaORcgyK77bSSNgk+u9WSjbH1uYIAIPSffUZ
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| 167 | bti+jc1dUg5wb+aeZlgJAkEAurrpmpqj5vg087ZngKfFGR5rozDiTsK5DceTV97K
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| 168 | a3Y+Nzl+XWTxDBWk4YPh2ZlKv402hZEfWBYxUDn5ZkH/bw==
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| 169 | -----END RSA PRIVATE KEY-----
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| 170 | ```
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| 171 |
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| 172 | This library simply takes keys in the following format, and translates it to those variables needed to perform the encryptions used in Tom Wu's library.
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| 173 |
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| 174 | Here are some good resources to investigate further.
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| 175 | - http://etherhack.co.uk/asymmetric/docs/rsa_key_breakdown.html
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| 176 | - http://www.di-mgt.com.au/rsa_alg.html
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| 177 | - https://polarssl.org/kb/cryptography/asn1-key-structures-in-der-and-pem
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| 178 |
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| 179 | With this information, we can translate a private key format to the variables
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| 180 | required with the jsbn library from Tom Wu by using the following mappings.
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| 181 |
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| 182 | ```
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| 183 | modulus => n
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| 184 | public exponent => e
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| 185 | private exponent => d
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| 186 | prime1 => p
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| 187 | prime2 => q
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| 188 | exponent1 => dmp1
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| 189 | exponent2 => dmq1
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| 190 | coefficient => coeff
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| 191 | ```
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| 192 |
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