Applications of Symmetric Encryption and Asymmetric Encryption
Original text from: Potter’s personal blog
Summary content
What is Symmetric Encryption
Symmetric encryption demo
What is asymmetric encryption
Asymmetric encryption demo
Combination of symmetric encryption and asymmetric encryption
Introduce a set of feasible hybrid encryption schemes and how to apply them to interface data encryption
Demo source code project
What is symmetric encryption
Definition: > Symmetric key algorithm (English: Symmetric-key algorithm), also known as symmetric encryption, private key encryption, shared key encryption, is a type of encryption algorithm in cryptography. This type of algorithm uses the same key for encryption and decryption, or uses two keys that can be easily calculated from each other* Advantages: > The algorithm is public, the amount of calculation is small, the encryption speed is fast, and the encryption efficiency is high, suitable for large amounts of data Encrypted scenarios. For example, in HLS (HTTP Live Streaming) general encryption scenarios, AES-128 symmetric encryption algorithm is generally used to encrypt TS slices to ensure the security of multimedia resources* Disadvantages: > The security is not high, as long as you get the secret key, you can encrypt Unlock* The process of symmetric encryption: > The sender uses the key to encrypt the plaintext data into ciphertext, and then sends it out. After receiving the ciphertext, the receiver uses the same key to decrypt the ciphertext into plaintext. Read
What is asymmetric encryption
Definition: > An asymmetric encryption algorithm requires two keys: a public key (publickey: public key for short) and a private key (privatekey: private key for short). The public key and the private key are a pair. If the data is encrypted with the public key, it can only be decrypted with the corresponding private key. Because two different keys are used for encryption and decryption, this algorithm is called an asymmetric encryption algorithm* Advantages: > Higher security, the public key is public, the private key is kept by itself, and there is no need to store the private key Provide the key to others* Disadvantages> Encryption and decryption are slow, only suitable for small data encryption and decryption* Symmetric encryption process:
* Personal understanding: > Symmetric encryption is like a key to a lock. A combination box stores things. If you have the key, you can take the treasure in the combination box* *”></li>
</ul>
<h3>Symmetric encryption demo</h3>
<pre>this.key = CryptoJS.enc.Utf8.parse()
* Personal understanding> Asymmetric encryption: the public key is like an unlocked lockbox, only things can be stored Go in and lock it. The secret key is like the key of a lockbox, you can open the secret box and take away the treasure inside* Asymmetric encryption demo“ “><br /> this.rsaEncryptor = new JSEncrypt();<br /> this.rsaEncryptor.setPublicKey(this.rsa_pub_key);<br /> this.rsaDecryptor = new JSEncrypt();<br /> this.rsaDecryptor.setPrivateKey(this.rsa_pri_key);</li>
</ul>
<p>/**</p>
<p><center></center></p>
<ul>
<li>RSA encryption</li>
<li>@param content</li>
<li>@returns {CipherParams|PromiseLike}</li>
<li>@private<br /> <em>/<br /> __rsaEncrypt(content) {return this.rsaEncryptor.encrypt(content);<br /> },<br /> /</em>*</li>
<li>RSA decryption</li>
<li>@param content</li>
<li>@returns {WordArray|PromiseLike}</li>
<li>@private<br /> */<br /> __rsaDecrypt(content) {return this.rsaDecryptor.decrypt(content);<br /> },</li>
</ul>
<pre>
* * *
### Combination of symmetric encryption and asymmetric encryption
> Now that we all know the disadvantages of symmetric encryption and asymmetric encryption, let’s make a demo combining the advantages of symmetric encryption and asymmetric encryption. data adopts symmetric encryption.
</pre>
<p>/**</p>
<ul>
<li>hybrid encryption</li>
<li>@param iv</li>
<li>@param key</li>
<li>@param content</li>
<li>@returns {<!-- -->{data: string, iv: (CipherParams|PromiseLike), key: (CipherParams|PromiseLike)}}</li>
<li>@private<br /> */<br /> __hybirdEncrypt(iv, key, content) {const aesEncryptData = this.__aesEncrypt(iv, key, content);const rsaEncryptIv = this.__rsaEncrypt(iv);const rsaEncryptKey = this.__rsaEncrypt(key);return {iv: rsaEncryptIv,key : rsaEncryptKey,data: aesEncryptData,};<br /> },</li>
</ul>
<p>/**</p>
<ul>
<li>hybrid decryption</li>
<li>@param encryptInfo</li>
<li>@returns {string}</li>
<li>@private<br /> */<br /> __hybirdDecrypt(encryptInfo) { const iv = this.rsaDecryptor.decrypt(encryptInfo.iv); const key = this.rsaDecryptor.decrypt(encryptInfo.key); const data = encryptInfo.data; return this.__aesDecrypt(iv, key, data );<br /> }</li>
</ul>
<pre>
* * *
### Introduce a set of feasible hybrid encryption schemes and how to apply them to interface data encryption. The flow chart is as follows:
* The idea is as follows: * Step 1: Create a set of RSA public and private keys, the front end holds the public key, and the private key server holds * Step 2: The front end generates RequestID for each network request* Step 3: The client generates AES Key, then use RequestID as Key, and AES Key as Value to store in memory* Step 4: The client encrypts the request data Request Data with the generated AES Key, encrypts the AES Key with the RSA public key, and simultaneously stores the requestID, encrypted data, and encrypted AES Key is sent to the server* Step 5: The server uses the RSA private key to decrypt the encrypted AES Key, and then uses the unlocked AES Key to decrypt the RequestData data* Step 6: The server uses the AES Key to respond to the data ResposneData encryption + RequestID, return to the front-end * Step 7: The front-end takes out the AES key in the memory according to the RequestID returned by the server, uses the AES key to decrypt the Resposne Data data, and deletes the AES key data in the Memory RequestID after use. * Finally: the front end creates an AES Key to encrypt data every time it sends a request. After receiving the response data from the server and decrypting the data, it deletes the AES Key data in the memory. In this way, a set of RSA public and private keys is used to solve the mixed encryption problem
* Flowchart: <img src=)