Learn cryptographic algorithms in Golang from scratch

"Learning cryptographic algorithms in Golang from scratch"

Cryptographic algorithms are a very important part of the computer field, and they involve data security and encryption technology. . This article will take the Golang language as an example and use actual code examples to help you learn the basic principles and implementation methods of cryptographic algorithms from scratch.

1. Hash algorithm

The hash algorithm is an important part of the cryptographic algorithm and is usually used to convert data of any length into a fixed-length hash value. Golang provides a variety of hash algorithm implementations, such as MD5, SHA-1, SHA-256, etc. Below we take SHA-256 as an example to show how to use Golang to implement hash algorithms:

package main

import (
    "crypto/sha256"
    "fmt"
)

func main() {
    data := []byte("Hello, World!")
    hash := sha256.Sum256(data)
    fmt.Printf("SHA-256 哈希值为：%x
", hash)
}

Above In the code, we first imported the crypto/sha256 package, then used the sha256.Sum256() method to calculate the SHA-256 hash value of the given data, and finally converted the result into ten Output in hexadecimal format.

2. Symmetric encryption algorithm

The symmetric encryption algorithm is a commonly used encryption algorithm in cryptography, which uses the same key for encryption and decryption. Golang provides various implementations of symmetric encryption algorithms, such as the AES algorithm. Below we take the AES algorithm as an example to show how to use Golang for symmetric encryption:

package main

import (
    "crypto/aes"
    "crypto/cipher"
    "crypto/rand"
    "encoding/hex"
    "fmt"
    "io"
)

func main() {
    key := []byte("thisisaverysecurekey")
    plaintext := []byte("Hello, World!")

    block, err := aes.NewCipher(key)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }

    ciphertext := make([]byte, aes.BlockSize+len(plaintext))
    iv := ciphertext[:aes.BlockSize]
    if _, err := io.ReadFull(rand.Reader, iv); err != nil {
        fmt.Println("Error:", err)
        return
    }

    mode := cipher.NewCBCEncrypter(block, iv)
    mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)

    fmt.Printf("AES 加密后的密文：%s
", hex.EncodeToString(ciphertext))
}

In the above code, we first define the keykey and plaintext plaintext, then use the AES algorithm to encrypt the plaintext, and finally output the encrypted ciphertext in hexadecimal form.

3. Asymmetric encryption algorithm

Asymmetric encryption algorithm is another commonly used encryption algorithm in cryptography. It uses a pair of keys for encryption and decryption, which are called public keys respectively. and private key. Golang provides a variety of implementations of asymmetric encryption algorithms, such as the RSA algorithm. Below we take the RSA algorithm as an example to show how to use Golang for asymmetric encryption:

package main

import (
    "crypto/rand"
    "crypto/rsa"
    "crypto/x509"
    "encoding/pem"
    "fmt"
)

func main() {
    privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }

    publicKey := &privateKey.PublicKey

    plaintext := []byte("Hello, World!")

    ciphertext, err := rsa.EncryptPKCS1v15(rand.Reader, publicKey, plaintext)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }

    fmt.Printf("RSA 加密后的密文：%x
", ciphertext)
}

In the above code, we first generate RSA Key pair privateKey and publicKey, then use the public key to encrypt the plain text, and finally output the encrypted cipher text in hexadecimal form.

Through the above examples, we have learned how to use Golang to implement hash algorithms, symmetric encryption algorithms and asymmetric encryption algorithms in cryptographic algorithms. In actual development, reasonable selection and correct use of cryptographic algorithms can effectively ensure data security. I hope this article will be helpful to you.

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