v1.1.0: add ssh fingerprint

README.md

@@ -11,6 +11,7 @@ Features
 &lt; 100 lines of code | <1kb gzipped | 1.8kb minified | 3.1kb with comments
 
 * [x] SSH Public Keys
+  * fingerprint
 * [x] RSA Public Keys
 * [x] EC Public Keys
   * P-256 (prime256v1, secp256r1)
@@ -47,18 +48,32 @@ ssh-to-jwk ~/.ssh/id_rsa.pub
 
 You can also use it from JavaScript:
 
+**SSH to JWK**
+
 ```js
 var fs = require('fs');
 var sshtojwk = require('ssh-to-jwk');
 
 var pub = fs.readFileSync("./id_rsa.pub");
-var ssh = sshtojwk.parse(pub);
+var ssh = sshtojwk.parse({ pub: pub });
 
 console.info(ssh.jwk);
 ```
 
-Legal
------
+**SSH Fingerprint**
+
+```js
+var fs = require('fs');
+var sshtojwk = require('ssh-to-jwk');
+var pub = fs.readFileSync("./id_rsa.pub");
+
+sshtojwk.fingerprint({ pub: pub }).then(function (fingerprint) {
+  console.info(fingerprint);
+  // SHA256:yCB62vBVsOwqksgYwy/WDbaMF2PhPijAwcrlzmrxfko
+});
+```
+
+# Legal
 
 [ssh-to-jwk.js](https://git.coolaj86.com/coolaj86/ssh-to-jwk.js) |
 MPL-2.0 |

bin/ssh-to-jwk.js

@@ -12,6 +12,11 @@ if (!pubfile) {
 }
 
 var buf = fs.readFileSync(pubfile);
-var ssh = sshtojwk.parse(buf.toString('ascii'));
+var pub = buf.toString('ascii');
+var ssh = sshtojwk.parse({ pub: pub });
 
-console.info(JSON.stringify(ssh.jwk, null, 2));
+// Finally! https://superuser.com/a/714195
+sshtojwk.fingerprint({ pub: pub }).then(function (fingerprint) {
+  console.warn('The key fingerprint is:\n' + fingerprint + ' ' + ssh.comment);
+  console.info(JSON.stringify(ssh.jwk, null, 2));
+});

lib/ssh-parser.js

@@ -3,49 +3,37 @@
 var SSH = module.exports;
 var Enc = require('./encoding.js');
 
-SSH.parse = function (ssh) {
+SSH.parse = function (opts) {
+  var pub = opts.pub || opts;
+  var ssh = SSH.parseBlock(pub);
+  ssh = SSH.parseElements(ssh);
+  //delete ssh.bytes;
+  return SSH.parsePublicKey(ssh);
+};
+
+/*global Promise*/
+SSH.fingerprint = function (opts) {
+  var ssh;
+  if (opts.bytes) {
+    ssh = opts;
+  } else {
+    ssh = SSH.parseBlock(opts.pub);
+  }
+  // for browser compat
+  return Promise.resolve().then(function () {
+    return 'SHA256:' + require('crypto').createHash('sha256')
+      .update(ssh.bytes).digest('base64').replace(/=+$/g, '');
+  });
+};
+
+SSH.parseBlock = function (ssh) {
   ssh = ssh.split(/\s+/g);
 
-  var result = { type: ssh[0], jwk: null, comment: ssh[2] || '' };
-  var buf = Enc.base64ToBuf(ssh[1]);
-  var els = SSH.parseElements({ bytes: buf }).elements;
-  var typ = Enc.bufToBin(els[0]);
-  var len;
-
-  // RSA keys are all the same
-  if (SSH.types.rsa === typ) {
-    result.jwk = {
-      kty: 'RSA'
-    , n: Enc.bufToUrlBase64(els[2])
-    , e: Enc.bufToUrlBase64(els[1])
-    };
-    return result;
-  }
-
-  // EC keys are each different
-  if (SSH.types.p256 === typ) {
-    len = 32;
-    result.jwk = { kty: 'EC', crv: 'P-256' };
-  } else if (SSH.types.p384 === typ) {
-    len = 48;
-    result.jwk = { kty: 'EC', crv: 'P-384' };
-  } else {
-    throw new Error("Unsupported ssh public key type: "
-      + Enc.bufToBin(els[0]));
-  }
-
-  // els[1] is just a repeat of a subset of els[0]
-  var x = els[2].slice(1, 1 + len);
-  var y = els[2].slice(1 + len, 1 + len + len);
-
-  // I don't think EC keys use 0x00 padding, but just in case
-  while (0x00 === x[0]) { x = x.slice(1); }
-  while (0x00 === y[0]) { y = y.slice(1); }
-
-  result.jwk.x = Enc.bufToUrlBase64(x);
-  result.jwk.y = Enc.bufToUrlBase64(y);
-
-  return result;
+  return {
+    type: ssh[0]
+  , bytes: Enc.base64ToBuf(ssh[1])
+  , comment: ssh[2]
+  };
 };
 
 SSH.parseElements = function (ssh) {
@@ -74,15 +62,56 @@ SSH.parseElements = function (ssh) {
     index += len;
   }
   if (fulllen !== index) {
-    throw new Error(els.map(function (b) {
+    throw new Error("invalid ssh public key length \n" + els.map(function (b) {
       return Enc.bufToHex(b);
-    }).join('\n') + "invalid ssh public key length");
+    }).join('\n'));
   }
 
   ssh.elements = els;
   return ssh;
 };
 
+SSH.parsePublicKey = function (ssh) {
+  var els = ssh.elements;
+  var typ = Enc.bufToBin(els[0]);
+  var len;
+
+  // RSA keys are all the same
+  if (SSH.types.rsa === typ) {
+    ssh.jwk = {
+      kty: 'RSA'
+    , n: Enc.bufToUrlBase64(els[2])
+    , e: Enc.bufToUrlBase64(els[1])
+    };
+    return ssh;
+  }
+
+  // EC keys are each different
+  if (SSH.types.p256 === typ) {
+    len = 32;
+    ssh.jwk = { kty: 'EC', crv: 'P-256' };
+  } else if (SSH.types.p384 === typ) {
+    len = 48;
+    ssh.jwk = { kty: 'EC', crv: 'P-384' };
+  } else {
+    throw new Error("Unsupported ssh public key type: "
+      + Enc.bufToBin(els[0]));
+  }
+
+  // els[1] is just a repeat of a subset of els[0]
+  var x = els[2].slice(1, 1 + len);
+  var y = els[2].slice(1 + len, 1 + len + len);
+
+  // I don't think EC keys use 0x00 padding, but just in case
+  while (0x00 === x[0]) { x = x.slice(1); }
+  while (0x00 === y[0]) { y = y.slice(1); }
+
+  ssh.jwk.x = Enc.bufToUrlBase64(x);
+  ssh.jwk.y = Enc.bufToUrlBase64(y);
+
+  return ssh;
+};
+
 SSH.types = {
   // 19 '00000013'
   // e c d s a - s h a 2 - n i s t p 2 5 6

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ssh-to-jwk",
-  "version": "1.0.2",
+  "version": "1.1.0",
   "description": "💯 SSH to JWK in a lightweight, zero-dependency library.",
   "homepage": "https://git.coolaj86.com/coolaj86/ssh-to-jwk.js",
   "main": "index.js",
@@ -29,6 +29,7 @@
     "RSA",
     "EC",
     "SSH",
+    "fingerprint",
     "JWK",
     "ECDSA"
   ],