GO NewCTR用法及代码示例

package main

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

func main() {
    // Load your secret key from a safe place and reuse it across multiple
    // NewCipher calls. (Obviously don't use this example key for anything
    // real.) If you want to convert a passphrase to a key, use a suitable
    // package like bcrypt or scrypt.
    key, _ := hex.DecodeString("6368616e676520746869732070617373")
    plaintext := []byte("some plaintext")

    block, err := aes.NewCipher(key)
    if err != nil {
        panic(err)
    }

    // The IV needs to be unique, but not secure. Therefore it's common to
    // include it at the beginning of the ciphertext.
    ciphertext := make([]byte, aes.BlockSize+len(plaintext))
    iv := ciphertext[:aes.BlockSize]
    if _, err := io.ReadFull(rand.Reader, iv); err != nil {
        panic(err)
    }

    stream := cipher.NewCTR(block, iv)
    stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)

    // It's important to remember that ciphertexts must be authenticated
    // (i.e. by using crypto/hmac) as well as being encrypted in order to
    // be secure.

    // CTR mode is the same for both encryption and decryption, so we can
    // also decrypt that ciphertext with NewCTR.

    plaintext2 := make([]byte, len(plaintext))
    stream = cipher.NewCTR(block, iv)
    stream.XORKeyStream(plaintext2, ciphertext[aes.BlockSize:])

    fmt.Printf("%s\n", plaintext2)
}

some plaintext