NewCFBDecrypter in Go

Posted by GoDoc

Public (Editable by Users)

NewCFBDecrypter returns a Stream which decrypts with cipher feedback mode, using the given Block. The iv must be the same length as the Block's block size.

Language Go

Dependencies

import "crypto/aes"

import "crypto/cipher"

import "encoding/hex"

import "fmt"

aes.BlockSize

aes.NewCipher()

cipher.NewCFBDecrypter()

fmt.Printf()

hex.DecodeString()

Edit

main.go

package main

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

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")
	ciphertext, _ := hex.DecodeString("7dd015f06bec7f1b8f6559dad89f4131da62261786845100056b353194ad")

	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.
	if len(ciphertext) < aes.BlockSize {
		panic("ciphertext too short")
	}
	iv := ciphertext[:aes.BlockSize]
	ciphertext = ciphertext[aes.BlockSize:]

	stream := cipher.NewCFBDecrypter(block, iv)

	// XORKeyStream can work in-place if the two arguments are the same.
	stream.XORKeyStream(ciphertext, ciphertext)
	fmt.Printf("%s", ciphertext)
}

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