doc: update examples in api/crypto.md

* var -> const / let in crypto.md
* fix error in crypto.md code example
* equal -> strictEqual, == -> === in crypto.md
* update estimated outputs in crypto.md
* snake_case -> camelCase in crypto.md examples
* concatenation -> multiline template in crypto
* add missing line break in crypto code example
* add missing link reference in crypto.md

PR-URL: #10909
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: vsemozhetbyt

doc/api/crypto.md

@@ -26,7 +26,7 @@ It is possible for Node.js to be built without including support for the
 error being thrown.
 
 ```js
-var crypto;
+let crypto;
 try {
   crypto = require('crypto');
 } catch (err) {
@@ -132,9 +132,9 @@ Example: Using `Cipher` objects as streams:
 const crypto = require('crypto');
 const cipher = crypto.createCipher('aes192', 'a password');
 
-var encrypted = '';
+let encrypted = '';
 cipher.on('readable', () => {
-  var data = cipher.read();
+  const data = cipher.read();
   if (data)
     encrypted += data.toString('hex');
 });
@@ -166,7 +166,7 @@ Example: Using the [`cipher.update()`][] and [`cipher.final()`][] methods:
 const crypto = require('crypto');
 const cipher = crypto.createCipher('aes192', 'a password');
 
-var encrypted = cipher.update('some clear text data', 'utf8', 'hex');
+let encrypted = cipher.update('some clear text data', 'utf8', 'hex');
 encrypted += cipher.final('hex');
 console.log(encrypted);
 // Prints: ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504
@@ -265,9 +265,9 @@ Example: Using `Decipher` objects as streams:
 const crypto = require('crypto');
 const decipher = crypto.createDecipher('aes192', 'a password');
 
-var decrypted = '';
+let decrypted = '';
 decipher.on('readable', () => {
-  var data = decipher.read();
+  const data = decipher.read();
   if (data)
     decrypted += data.toString('utf8');
 });
@@ -276,7 +276,7 @@ decipher.on('end', () => {
   // Prints: some clear text data
 });
 
-var encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
+const encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
 decipher.write(encrypted, 'hex');
 decipher.end();
 ```
@@ -300,8 +300,8 @@ Example: Using the [`decipher.update()`][] and [`decipher.final()`][] methods:
 const crypto = require('crypto');
 const decipher = crypto.createDecipher('aes192', 'a password');
 
-var encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
-var decrypted = decipher.update(encrypted, 'hex', 'utf8');
+const encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
+let decrypted = decipher.update(encrypted, 'hex', 'utf8');
 decrypted += decipher.final('utf8');
 console.log(decrypted);
 // Prints: some clear text data
@@ -392,18 +392,18 @@ const assert = require('assert');
 
 // Generate Alice's keys...
 const alice = crypto.createDiffieHellman(2048);
-const alice_key = alice.generateKeys();
+const aliceKey = alice.generateKeys();
 
 // Generate Bob's keys...
 const bob = crypto.createDiffieHellman(alice.getPrime(), alice.getGenerator());
-const bob_key = bob.generateKeys();
+const bobKey = bob.generateKeys();
 
 // Exchange and generate the secret...
-const alice_secret = alice.computeSecret(bob_key);
-const bob_secret = bob.computeSecret(alice_key);
+const aliceSecret = alice.computeSecret(bobKey);
+const bobSecret = bob.computeSecret(aliceKey);
 
 // OK
-assert.equal(alice_secret.toString('hex'), bob_secret.toString('hex'));
+assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));
 ```
 
 ### diffieHellman.computeSecret(other_public_key[, input_encoding][, output_encoding])
@@ -521,17 +521,17 @@ const assert = require('assert');
 
 // Generate Alice's keys...
 const alice = crypto.createECDH('secp521r1');
-const alice_key = alice.generateKeys();
+const aliceKey = alice.generateKeys();
 
 // Generate Bob's keys...
 const bob = crypto.createECDH('secp521r1');
-const bob_key = bob.generateKeys();
+const bobKey = bob.generateKeys();
 
 // Exchange and generate the secret...
-const alice_secret = alice.computeSecret(bob_key);
-const bob_secret = bob.computeSecret(alice_key);
+const aliceSecret = alice.computeSecret(bobKey);
+const bobSecret = bob.computeSecret(aliceKey);
 
-assert(alice_secret, bob_secret);
+assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));
   // OK
 ```
 
@@ -638,13 +638,14 @@ alice.setPrivateKey(
 );
 
 // Bob uses a newly generated cryptographically strong
-// pseudorandom key pair bob.generateKeys();
+// pseudorandom key pair
+bob.generateKeys();
 
-const alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
-const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
 
-// alice_secret and bob_secret should be the same shared secret value
-console.log(alice_secret === bob_secret);
+// aliceSecret and bobSecret should be the same shared secret value
+console.log(aliceSecret === bobSecret);
 ```
 
 ## Class: Hash
@@ -670,7 +671,7 @@ const crypto = require('crypto');
 const hash = crypto.createHash('sha256');
 
 hash.on('readable', () => {
-  var data = hash.read();
+  const data = hash.read();
   if (data)
     console.log(data.toString('hex'));
     // Prints:
@@ -753,7 +754,7 @@ const crypto = require('crypto');
 const hmac = crypto.createHmac('sha256', 'a secret');
 
 hmac.on('readable', () => {
-  var data = hmac.read();
+  const data = hmac.read();
   if (data)
     console.log(data.toString('hex'));
     // Prints:
@@ -837,8 +838,8 @@ const sign = crypto.createSign('RSA-SHA256');
 sign.write('some data to sign');
 sign.end();
 
-const private_key = getPrivateKeySomehow();
-console.log(sign.sign(private_key, 'hex'));
+const privateKey = getPrivateKeySomehow();
+console.log(sign.sign(privateKey, 'hex'));
 // Prints: the calculated signature
 ```
 
@@ -850,8 +851,8 @@ const sign = crypto.createSign('RSA-SHA256');
 
 sign.update('some data to sign');
 
-const private_key = getPrivateKeySomehow();
-console.log(sign.sign(private_key, 'hex'));
+const privateKey = getPrivateKeySomehow();
+console.log(sign.sign(privateKey, 'hex'));
 // Prints: the calculated signature
 ```
 
@@ -868,13 +869,14 @@ const sign = crypto.createSign('sha256');
 
 sign.update('some data to sign');
 
-const private_key = '-----BEGIN EC PRIVATE KEY-----\n' +
-        'MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49\n' +
-        'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2\n' +
-        'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
-        '-----END EC PRIVATE KEY-----\n';
+const privateKey =
+`-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49
+AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2
+pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==
+-----END EC PRIVATE KEY-----`;
 
-console.log(sign.sign(private_key).toString('hex'));
+console.log(sign.sign(privateKey).toString('hex'));
 ```
 
 ### sign.sign(private_key[, output_format])
@@ -937,9 +939,9 @@ const verify = crypto.createVerify('RSA-SHA256');
 verify.write('some data to sign');
 verify.end();
 
-const public_key = getPublicKeySomehow();
+const publicKey = getPublicKeySomehow();
 const signature = getSignatureToVerify();
-console.log(verify.verify(public_key, signature));
+console.log(verify.verify(publicKey, signature));
 // Prints: true or false
 ```
 
@@ -951,9 +953,9 @@ const verify = crypto.createVerify('RSA-SHA256');
 
 verify.update('some data to sign');
 
-const public_key = getPublicKeySomehow();
+const publicKey = getPublicKeySomehow();
 const signature = getSignatureToVerify();
-console.log(verify.verify(public_key, signature));
+console.log(verify.verify(publicKey, signature));
 // Prints: true or false
 ```
 
@@ -1182,7 +1184,7 @@ const hash = crypto.createHash('sha256');
 
 const input = fs.createReadStream(filename);
 input.on('readable', () => {
-  var data = input.read();
+  const data = input.read();
   if (data)
     hash.update(data);
   else {
@@ -1216,7 +1218,7 @@ const hmac = crypto.createHmac('sha256', 'a secret');
 
 const input = fs.createReadStream(filename);
 input.on('readable', () => {
-  var data = input.read();
+  const data = input.read();
   if (data)
     hmac.update(data);
   else {
@@ -1268,7 +1270,7 @@ Example:
 
 ```js
 const curves = crypto.getCurves();
-console.log(curves); // ['secp256k1', 'secp384r1', ...]
+console.log(curves); // ['Oakley-EC2N-3', 'Oakley-EC2N-4', ...]
 ```
 
 ### crypto.getDiffieHellman(group_name)
@@ -1297,11 +1299,11 @@ const bob = crypto.getDiffieHellman('modp14');
 alice.generateKeys();
 bob.generateKeys();
 
-const alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
-const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
 
-/* alice_secret and bob_secret should be the same */
-console.log(alice_secret == bob_secret);
+/* aliceSecret and bobSecret should be the same */
+console.log(aliceSecret === bobSecret);
 ```
 
 ### crypto.getHashes()
@@ -1316,7 +1318,7 @@ Example:
 
 ```js
 const hashes = crypto.getHashes();
-console.log(hashes); // ['sha', 'sha1', 'sha1WithRSAEncryption', ...]
+console.log(hashes); // ['DSA', 'DSA-SHA', 'DSA-SHA1', ...]
 ```
 
 ### crypto.pbkdf2(password, salt, iterations, keylen, digest, callback)
@@ -1347,7 +1349,7 @@ Example:
 const crypto = require('crypto');
 crypto.pbkdf2('secret', 'salt', 100000, 512, 'sha512', (err, key) => {
   if (err) throw err;
-  console.log(key.toString('hex'));  // 'c5e478d...1469e50'
+  console.log(key.toString('hex'));  // '3745e48...aa39b34'
 });
 ```
 
@@ -1380,7 +1382,7 @@ Example:
 ```js
 const crypto = require('crypto');
 const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 512, 'sha512');
-console.log(key.toString('hex'));  // 'c5e478d...1469e50'
+console.log(key.toString('hex'));  // '3745e48...aa39b34'
 ```
 
 An array of supported digest functions can be retrieved using
@@ -1928,6 +1930,7 @@ the `crypto`, `tls`, and `https` modules and are generally specific to OpenSSL.
 [`crypto.createHash()`]: #crypto_crypto_createhash_algorithm
 [`crypto.createHmac()`]: #crypto_crypto_createhmac_algorithm_key
 [`crypto.createSign()`]: #crypto_crypto_createsign_algorithm
+[`crypto.createVerify()`]: #crypto_crypto_createverify_algorithm
 [`crypto.getCurves()`]: #crypto_crypto_getcurves
 [`crypto.getHashes()`]: #crypto_crypto_gethashes
 [`crypto.pbkdf2()`]: #crypto_crypto_pbkdf2_password_salt_iterations_keylen_digest_callback