How To Decrypt doument in golang which is encrypted in Node Js?

Getting Help
1

Using same “Crypto” Module aes-256-gcm , base64 encoding and With IV = 16!!
decrypt document which was encrypted in Nodejs with IV=16 & setAuthTag Use key which was any 32 or 64 char long and to decrypt golang i used crypto/cipher , crypto/aes to decrypt encrypted document in Nodejs

2

I found solution.:+1:

package main

import (
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"encoding/hex"
"fmt"
"strings"
)

const (
ivBytes   = 16
algorithm = "aes-256-gcm"
secureKey = "<Your Secure Key>"
)

func main() {
doc := "<Your Encrypted String>"

decrypted, err := decrypt(doc)
if err != nil {
    fmt.Println("Decryption error:", err)
    return
}
fmt.Println("Encrypted text:", decrypted)
}

func decrypt(encrypted string) (string, error) {
// Split the encrypted string into ciphertext, IV, and authentication tag
data := strings.Split(encrypted, ".")
fmt.Println("Data[0]:", data[0])
fmt.Println("Data[1]:", data[1])
fmt.Println("Data[2]:", data[2])
if len(data) != 3 {
    return "", fmt.Errorf("invalid encrypted string format")
}

// Decode base64 strings
ciphertext, err := base64.StdEncoding.DecodeString(data[0])
if err != nil {
    return "", err
}
fmt.Println("CipherTextDecodeString:=", ciphertext)

iv, err := base64.StdEncoding.DecodeString(data[1])
if err != nil {
    return "", err
}
fmt.Println("Length IV=", len(iv))
fmt.Println("IV values=", iv)

authTag, err := base64.StdEncoding.DecodeString(data[2])
if err != nil {
    return "", err
}
fmt.Println("authTag values=", authTag)

//Use this to getAuthTag which is setAuthTag Method setting AuthTag in NodeJs
ciphertext = append(ciphertext, authTag...)

// Decode the secure key from hex
key, err := hex.DecodeString(secureKey)
if err != nil {
    return "", err
}
fmt.Println("key values=", key)

// Create the AES cipher block using the decoded key
block, err := aes.NewCipher(key)
if err != nil {
    return "", err
}
fmt.Println("block values=", key)

aesgcm, err := cipher.NewGCMWithNonceSize(block, ivBytes)//using this when you have IV=16 size or you can use cipher.NewGCM() when IV=12 size
if err != nil {
    return "", err
}
fmt.Println(aesgcm)

// Decrypt the ciphertext using the GCM mode
plaintext, err := aesgcm.Open(nil, iv, ciphertext, nil)
if err != nil {
    return "", fmt.Errorf("decryption failed: %v", err)
}

return string(plaintext), nil
3

Here’s the Golang code to decrypt the document, assuming you have the ciphertext, key, IV, and authentication tag:

`Gopackage main

import (
“crypto/aes”
“crypto/cipher”
“encoding/base64”
“fmt”
)

func main() {
// Ciphertext, key, IV, and authentication tag (base64-encoded strings)
ciphertextB64 := “your_ciphertext_base64”
keyB64 := “your_key_base64”
ivB64 := “your_iv_base64”
authTagB64 := “your_auth_tag_base64”

// Decode base64 strings
ciphertext, _ := base64.StdEncoding.DecodeString(ciphertextB64)
key, _ := base64.StdEncoding.DecodeString(keyB64)
iv, _ := base64.StdEncoding.DecodeString(ivB64)
authTag, _ := base64.StdEncoding.DecodeString(authTagB64)

// Create a new cipher block
block, err := aes.NewCipher(key)
if err != nil {
    // Handle error
    fmt.Println("Error creating cipher:", err)
    return
}

// Create a GCM cipher
aesgcm, err := cipher.NewGCM(block)
if err != nil {
    // Handle error
    fmt.Println("Error creating GCM:", err)
    return
}

// Decrypt the ciphertext
plaintext, err := aesgcm.Open(nil, iv, ciphertext, authTag)
if err != nil {
    // Handle decryption error
    fmt.Println("Decryption failed:", err)
    return
}

// Print the decrypted plaintext
fmt.Println("Decrypted plaintext:", string(plaintext))

}`

Use code with caution. Learn more

content_copy

Remember:

  • Replace placeholders with actual base64-encoded values for ciphertext, key, IV, and authentication tag.
  • Handle potential errors gracefully.
  • Ensure compatibility between Node.js and Golang encryption implementations.
  • Use secure key and IV handling practices.
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