func DecodePostPush(nbpp *PostPush, seed int64, passbytes []byte) (PostContent, error) {
var nbpc PostContent
bb := bytes.NewBuffer(nbpp.Content)
//get hash generated
res := hashIt(seed, passbytes)
//get our encrypter rolling
block, err := aes.NewCipher(res)
if err != nil {
return nbpc, err
}
stream := cipher.NewCFBDecrypter(block, nbpp.IV)
cryptrdr := cipher.StreamReader{S: stream, R: bb}
dec := gob.NewDecoder(cryptrdr)
if err := dec.Decode(&nbpc); err != nil {
return nbpc, err
}
//verify hash
if !CompareHash(nbpc.BP.hash(), nbpc.Hash) {
return nbpc, errors.New("Invalid post hash")
}
return nbpc, nil
}
func AesDecryptFd(inFile, outFile *os.File, key, iv []byte, ctp int) error {
block, err := aes.NewCipher(key)
if err != nil {
return err
}
var stream cipher.Stream
switch ctp {
case 1:
stream = cipher.NewCFBDecrypter(block, iv[:])
case 2:
stream = cipher.NewCTR(block, iv[:])
default:
stream = cipher.NewOFB(block, iv[:])
}
reader := &cipher.StreamReader{S: stream, R: inFile}
// Copy the input file to the output file, decrypting as we go.
if _, err := io.Copy(outFile, reader); err != nil {
return err
}
// Note that this example is simplistic in that it omits any
// authentication of the encrypted data. If you were actually to use
// StreamReader in this manner, an attacker could flip arbitrary bits in
// the output.
return nil
}
// Decrypt attempts to decrypt an encrypted session key. If it returns nil,
// ske.Key will contain the session key.
func (ske *SymmetricKeyEncrypted) Decrypt(passphrase []byte) error {
if !ske.Encrypted {
return nil
}
key := make([]byte, ske.CipherFunc.KeySize())
ske.s2k(key, passphrase)
if len(ske.encryptedKey) == 0 {
ske.Key = key
} else {
// the IV is all zeros
iv := make([]byte, ske.CipherFunc.blockSize())
c := cipher.NewCFBDecrypter(ske.CipherFunc.new(key), iv)
c.XORKeyStream(ske.encryptedKey, ske.encryptedKey)
ske.CipherFunc = CipherFunction(ske.encryptedKey[0])
if ske.CipherFunc.blockSize() == 0 {
return errors.UnsupportedError("unknown cipher: " + strconv.Itoa(int(ske.CipherFunc)))
}
ske.CipherFunc = CipherFunction(ske.encryptedKey[0])
ske.Key = ske.encryptedKey[1:]
if len(ske.Key)%ske.CipherFunc.blockSize() != 0 {
ske.Key = nil
return errors.StructuralError("length of decrypted key not a multiple of block size")
}
}
ske.Encrypted = false
return nil
}
func view(c *gin.Context) {
id := c.Param("uniuri")
key := c.Param("key")
re := models.ResourceEntry{}
remote := c.ClientIP()
db.Where(&models.ResourceEntry{Key: id}).First(&re)
if re.Key == "" {
log.Printf("[INFO][%s]\tNot found : %s", remote, id)
c.AbortWithStatus(http.StatusNotFound)
return
}
log.Printf("[INFO][%s]\tFetched %s file and entry\n", remote, id)
f, err := os.Open(path.Join(conf.C.UploadDir, re.Key))
if err != nil {
log.Printf("[ERROR][%s]\tWhile opening %s file\n", remote, id)
c.AbortWithStatus(http.StatusInternalServerError)
return
}
block, err := aes.NewCipher([]byte(key))
if err != nil {
log.Printf("[ERROR][%s]\tDuring Cipher creation : %s\n", remote, err)
c.String(http.StatusInternalServerError, "Something went wrong on the server side. Try again later.")
c.AbortWithStatus(http.StatusInternalServerError)
return
}
var iv [aes.BlockSize]byte
stream := cipher.NewCFBDecrypter(block, iv[:])
reader := &cipher.StreamReader{S: stream, R: f}
c.Header("Content-Disposition", "filename=\""+re.Name+"\"")
io.Copy(c.Writer, reader)
}
func decrypt(str string) (plaintext string, err error) {
ciphertext, err := hex.DecodeString(str)
if err != nil {
return "", err
}
var block cipher.Block
if block, err = aes.NewCipher(AES_KEY); err != nil {
return
}
if len(ciphertext) < aes.BlockSize {
err = errors.New("ciphertext too short")
return
}
iv := ciphertext[:aes.BlockSize]
fmt.Println(iv)
ciphertext = ciphertext[aes.BlockSize:]
cfb := cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(ciphertext, ciphertext)
plaintext = string(ciphertext)
return
}
// Eecrypt from base64 to decrypted string
func Decrypt(keyStr, cryptoText string) (r string, err error) {
key := []byte(keyStr)
ciphertext, err := base64.URLEncoding.DecodeString(cryptoText)
if err != nil {
return
}
block, err := aes.NewCipher(key)
if err != nil {
return
}
// 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 {
err = errors.New("ciphertext too short")
return
}
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)
r = fmt.Sprintf("%s", ciphertext)
return
}
func Decrypt(key string, publickey PublicKey, rin io.Reader) (r io.Reader, length int64, sequence int64, e os.Error) {
c, e := simpleCipher(key)
if e != nil {
e = os.NewError("Trouble reading the symmetric key: " + e.String())
return
}
pub, e := readPublicKey(publickey)
if e != nil {
e = os.NewError("Trouble reading the public key: " + e.String())
return
}
iv := make([]byte, c.BlockSize())
_, e = io.ReadFull(rin, iv) // read the iv first (it's not encrypted)
if e != nil {
e = os.NewError("Trouble reading the iv: " + e.String())
return
}
decrypter := cipher.NewCFBDecrypter(c, iv)
rdec := flate.NewReader(cipher.StreamReader{decrypter, rin})
e = binary.Read(rdec, binary.LittleEndian, &length)
if e != nil {
e = os.NewError("Trouble reading the file length: " + e.String())
return
}
e = binary.Read(rdec, binary.LittleEndian, &sequence)
if e != nil {
e = os.NewError("Trouble reading the serial number: " + e.String())
return
}
return &hashReader{rdec, sha256.New(), pub, length}, length, sequence, nil
}
// decryptAES derypts ciphertext input with passed key and mode (IV is contained in input)
// in AES block cipher; and returns plaintext output
func decryptAES(input []byte, output []byte, key []byte, mode Mode) error {
block, err := aes.NewCipher(key)
if err != nil {
return errors.New("Couldn't create block cipher.")
}
if len(input) < aes.BlockSize {
return errors.New("Ciphertext too short.")
}
iv := input[:aes.BlockSize]
ciphertext := input[aes.BlockSize:]
switch mode {
case CBC:
if len(input)%aes.BlockSize != 0 {
return errors.New("Ciphertext doesn't satisfy CBC-mode requirements.")
}
mode := cipher.NewCBCDecrypter(block, iv)
mode.CryptBlocks(output, ciphertext)
case CFB:
mode := cipher.NewCFBDecrypter(block, iv)
mode.XORKeyStream(output, ciphertext)
case CTR:
mode := cipher.NewCTR(block, iv)
mode.XORKeyStream(output, ciphertext)
case OFB:
mode := cipher.NewOFB(block, iv)
mode.XORKeyStream(output, ciphertext)
}
return nil
}
func AESDecrypt(c string, key string) (s string, err error) {
var k []byte
var block cipher.Block
var cfb cipher.Stream
var cb []byte
var iv []byte
k = AESMake256Key(key)
cb, err = hex.DecodeString(c)
if err != nil {
return
}
block, err = aes.NewCipher(k)
if err != nil {
return
}
if len(cb) < aes.BlockSize {
err = errors.New("crypt string is too short")
return
}
iv = cb[:aes.BlockSize]
cb = cb[aes.BlockSize:]
cfb = cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(cb, cb)
s = bytes.NewBuffer(cb).String()
return
}
func decryptFile(path string) {
fmt.Printf("UnLock: %s\n", path)
content, err := ioutil.ReadFile(path)
if err != nil {
panic(err.Error())
}
byteKey := sha256.Sum256([]byte(*key))
block, err := aes.NewCipher(byteKey[:])
if err != nil {
panic(err)
}
iv := content[:aes.BlockSize]
cyphertext := content[aes.BlockSize:]
plaintext := make([]byte, len(content)-aes.BlockSize)
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(plaintext, cyphertext)
f, err := os.Create(path[:len(path)-4])
if err != nil {
panic(err.Error())
}
_, err = io.Copy(f, bytes.NewReader(plaintext))
if err != nil {
panic(err.Error())
}
os.Remove(path)
}
func NewChiper(algo, secret string) (*Cipher, error) {
if algo == "rc4" {
c, err := rc4.NewCipher(truncateSecretToSize(secret, 32))
if err != nil {
return nil, err
}
return &Cipher{
enc: c,
dec: c,
}, nil
} else if algo == "aes" {
key := truncateSecretToSize(secret, 32)
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
return &Cipher{
enc: cipher.NewCFBEncrypter(c, key[:c.BlockSize()]),
dec: cipher.NewCFBDecrypter(c, key[:c.BlockSize()]),
}, nil
}
cipher, err := rc4.NewCipher([]byte(secret))
if err != nil {
return nil, err
}
return &Cipher{
enc: cipher,
dec: cipher,
}, nil
}
func main() {
// 原文本
pliantext := []byte("遊ぼうよ、和と")
if len(os.Args) > 1 {
pliantext = []byte(os.Args[1])
}
Println("原文本:", string(pliantext))
// 加密盐 长度必须为 16B(128b), 24B(192b), 32B(256b)
key_text := "最高の奇跡に乗り込め!!"
if len(os.Args) > 2 {
key_text = os.Args[2]
}
Println("盐", len(key_text), ":", key_text)
// 加密算法
c, err := aes.NewCipher([]byte(key_text))
if err != nil {
Printf("错误：NewCipher(%dB) = %s\n", len(key_text), err)
os.Exit(1)
}
// 实行加密
cfb := cipher.NewCFBEncrypter(c, commonIV)
ciphertext := make([]byte, len(pliantext))
cfb.XORKeyStream(ciphertext, pliantext)
Printf("%s=>%x\n", pliantext, ciphertext)
// 实行解密
cfbdec := cipher.NewCFBDecrypter(c, commonIV)
gettext := make([]byte, len(pliantext))
cfbdec.XORKeyStream(gettext, ciphertext)
Printf("%x=>%s\n", ciphertext, gettext)
}
func Decrypt(in io.Reader, key string) io.Reader {
buf := new(bytes.Buffer)
buf.ReadFrom(in)
s := buf.String()
// Load the ciphertext message you want to decrypt
ciphertext := []byte(s)
// Setup a key that will encrypt the other text.
h := sha256.New()
io.WriteString(h, key)
key_text := h.Sum(nil)
// We chose our cipher type here in this case we are using AES.
c, err := aes.NewCipher([]byte(key_text))
if err != nil {
fmt.Printf("Error: NewCipher(%d bytes) = %s", len(key_text), err)
os.Exit(-1)
}
// We use the CFBDecrypter in order to decrypt
// the whole stream of ciphertext using the
// cipher setup with c and a iv.
cfb := cipher.NewCFBDecrypter(c, commonIV)
plaintext := make([]byte, len(ciphertext))
cfb.XORKeyStream(plaintext, ciphertext)
return strings.NewReader(string(plaintext))
}
func FakioDial(server string, req []byte) (c *FakioConn, err error) {
conn, err := net.Dial("tcp", server)
if err != nil {
return nil, err
}
//handshake
key := stringToKey(fclient.PassWord)
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
enc := cipher.NewCFBEncrypter(block, req[0:16])
// 22 = iv + username
index := 16 + int(req[16]) + 1
enc.XORKeyStream(req[index:], req[index:])
if _, err := conn.Write(req); err != nil {
return nil, errors.New("handshake to server error")
}
hand := make([]byte, 64)
if _, err := conn.Read(hand); err != nil {
return nil, errors.New("handshake to server error")
}
dec := cipher.NewCFBDecrypter(block, hand[0:16])
dec.XORKeyStream(hand[16:], hand[16:])
cipher, err := NewCipher(hand[16:])
return &FakioConn{conn, cipher}, nil
}
// Unveil base64 decodes a slice of bytes and uses aes encryption to decrypt. It returns a decrypted slice of bytes,
// and an error. A CipherLengthError is returned if the data is less than 16 bytes.
func (cloak Cloak) Unveil(data []byte) ([]byte, error) {
decodedData := make([]byte, base64.URLEncoding.DecodedLen(len(data)))
n, err := base64.URLEncoding.Decode(decodedData, data)
if err != nil {
return []byte{}, err
}
decodedData = decodedData[:n]
if len(decodedData) < aes.BlockSize {
return []byte{}, CipherLengthError{}
}
initializationVector := decodedData[:aes.BlockSize]
decodedData = decodedData[aes.BlockSize:]
cipherDecrypter := cipher.NewCFBDecrypter(cloak.cipherBlock, initializationVector)
cipherDecrypter.XORKeyStream(decodedData, decodedData)
decoded := make([]byte, base64.StdEncoding.DecodedLen(len(decodedData)))
n, err = base64.StdEncoding.Decode(decoded, decodedData)
if err != nil {
return []byte{}, err
}
return decoded[:n], nil
}
func createDecryptorAES256(key []byte, ivSource []byte, input io.Reader) (reader io.Reader, err error) {
if len(key) != 32 {
return nil, ErrInvalidKey
}
// Normalize the iv
var iv [16]byte
for i, b := range ivSource {
iv[i] = b
if i >= 15 {
break
}
}
// Create new base cipher
blobCipher, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
// Generate the reader in CFB mode
return &cipher.StreamReader{
S: cipher.NewCFBDecrypter(
blobCipher,
iv[:]),
R: input},
nil
}
func ReadVMessUDP(buffer []byte, userset user.UserSet) (*VMessUDP, error) {
userHash := buffer[:user.IDBytesLen]
userId, timeSec, valid := userset.GetUser(userHash)
if !valid {
return nil, errors.NewAuthenticationError(userHash)
}
buffer = buffer[user.IDBytesLen:]
aesCipher, err := aes.NewCipher(userId.CmdKey())
if err != nil {
return nil, err
}
aesStream := cipher.NewCFBDecrypter(aesCipher, user.Int64Hash(timeSec))
aesStream.XORKeyStream(buffer, buffer)
fnvHash := binary.BigEndian.Uint32(buffer[:4])
fnv1a := fnv.New32a()
fnv1a.Write(buffer[4:])
fnvHashActual := fnv1a.Sum32()
if fnvHash != fnvHashActual {
log.Warning("Unexpected fhv hash %d, should be %d", fnvHashActual, fnvHash)
return nil, errors.NewCorruptedPacketError()
}
buffer = buffer[4:]
vmess := &VMessUDP{
user: *userId,
version: buffer[0],
token: binary.BigEndian.Uint16(buffer[1:3]),
}
// buffer[3] is reserved
port := binary.BigEndian.Uint16(buffer[4:6])
addrType := buffer[6]
var address v2net.Address
switch addrType {
case addrTypeIPv4:
address = v2net.IPAddress(buffer[7:11], port)
buffer = buffer[11:]
case addrTypeIPv6:
address = v2net.IPAddress(buffer[7:23], port)
buffer = buffer[23:]
case addrTypeDomain:
domainLength := buffer[7]
domain := string(buffer[8 : 8+domainLength])
address = v2net.DomainAddress(domain, port)
buffer = buffer[8+domainLength:]
default:
log.Warning("Unexpected address type %d", addrType)
return nil, errors.NewCorruptedPacketError()
}
vmess.address = address
vmess.data = buffer
return vmess, nil
}
func Decrypt(content string, orig []byte) (string, error) {
rawContent, err := base64.StdEncoding.DecodeString(content)
if err != nil {
return "", err
}
block, err := aes.NewCipher(orig)
if err != nil {
return "", err
}
// As cipher is random, IV is out of use.
iv := make([]byte, block.BlockSize())
stream := cipher.NewCFBDecrypter(block, iv)
res := make([]byte, len(rawContent))
stream.XORKeyStream(res, rawContent)
l := len(res) - ShaLength
if l < 0 {
return "", ErrValidation
}
s := sha1.New()
v := s.Sum(res[:l])[:ShaLength]
if !bytes.Equal(v, res[l:]) {
return "", ErrValidation
}
return string(res[:l]), nil
}
func main() {
plainText := []byte("Bob loves Alice.")
key := []byte("passw0rdpassw0rdpassw0rdpassw0rd")
// Create new DES cipher block
block, err := aes.NewCipher(key)
if err != nil {
fmt.Printf("err: %s\n", err)
}
// The IV (Initialization Vector) need to be unique, but not secure.
// Therefore, it's common to include it at the beginning of the cipher text.
cipherText := make([]byte, aes.BlockSize+len(plainText))
// Create IV
iv := cipherText[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
fmt.Printf("err: %s\n", err)
}
// Encrypt
encryptStream := cipher.NewCFBEncrypter(block, iv)
encryptStream.XORKeyStream(cipherText[aes.BlockSize:], plainText)
fmt.Printf("Cipher text: %v\n", cipherText)
// Decrpt
decryptedText := make([]byte, len(cipherText[aes.BlockSize:]))
decryptStream := cipher.NewCFBDecrypter(block, cipherText[:aes.BlockSize])
decryptStream.XORKeyStream(decryptedText, cipherText[aes.BlockSize:])
fmt.Printf("Decrypted text: %s\n", string(decryptedText))
}
func main() {
//需要去加密的字符串
plaintext := []byte("My name is Astaxie")
//如果传入加密串的话，plaint就是传入的字符串
if len(os.Args) > 1 {
plaintext = []byte(os.Args[1])
}
//des的加密字符串
key_text := "12345678"
if len(os.Args) > 2 {
key_text = os.Args[2]
}
fmt.Println(len(key_text))
// 创建加密算法des
c, err := des.NewCipher([]byte(key_text))
if err != nil {
fmt.Printf("Error: NewCipher(%d bytes) = %s", len(key_text), err)
os.Exit(-1)
}
//加密字符串
cfb := cipher.NewCFBEncrypter(c, commonIV)
ciphertext := make([]byte, len(plaintext))
cfb.XORKeyStream(ciphertext, plaintext)
fmt.Printf("%s=>%x\n", plaintext, ciphertext)
// 解密字符串
cfbdec := cipher.NewCFBDecrypter(c, commonIV)
plaintextCopy := make([]byte, len(plaintext))
cfbdec.XORKeyStream(plaintextCopy, ciphertext)
fmt.Printf("%x=>%s\n", ciphertext, plaintextCopy)
}
// NewAesDecryptionStream creates a new AES encryption stream based on given key and IV.
// Caller must ensure the length of key and IV is either 16, 24 or 32 bytes.
func NewAesDecryptionStream(key []byte, iv []byte) cipher.Stream {
aesBlock, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
return cipher.NewCFBDecrypter(aesBlock, iv)
}
func decryptAes(hexKey string, ciphertext string) (string, error) {
key, err := hex2Bin(hexKey)
if err != nil {
panic(err)
}
text, err := decodeBase64(ciphertext)
if err != nil {
return "", err
}
block, err := aes.NewCipher([]byte(key))
if err != nil {
panic(err)
}
if len(text) < aes.BlockSize {
panic("ciphertext too short")
}
iv := text[:aes.BlockSize]
text = text[aes.BlockSize:]
cfb := cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(text, text)
temp, err := decodeBase64(string(text))
if err != nil {
return "", err
}
return string(temp), nil
}
func DecryptAESCFB(src, key []byte) *AuthToken {
encrData := EncrData{}
err := json.Unmarshal(src, &encrData)
if err != nil {
return nil
}
if len(encrData.IV) != len(key) {
return nil
}
rawBytes := make([]byte, len(encrData.Data))
cipher.NewCFBDecrypter(aesCipher(key), encrData.IV).XORKeyStream(rawBytes, encrData.Data)
rawData := RawData{}
err = json.Unmarshal(rawBytes, &rawData)
if err != nil {
return nil
}
cSum := crc32.ChecksumIEEE(rawData.Data)
if cSum != rawData.CSum {
return nil
}
res := AuthToken{}
err = json.Unmarshal(rawData.Data, &res)
if err != nil {
return nil
}
return &res
}
func sc_aes_crypt(isEncrypt bool, engine_boots, engine_time int, msg_salt, key, data []byte) error {
if 0 == len(data) {
return fmt.Errorf("len(input_data) != 0, actual len is 0")
}
if 8 != len(msg_salt) {
return fmt.Errorf("len(msg_salt) != 8, actual len is %d", len(msg_salt))
}
initVec := make([]byte, 8+len(msg_salt))
binary.BigEndian.PutUint32(initVec, uint32(engine_boots))
binary.BigEndian.PutUint32(initVec[4:], uint32(engine_time))
copy(initVec[8:], msg_salt)
block, err := aes.NewCipher(key)
if nil != err {
return err
}
if isEncrypt {
cipher.NewCFBEncrypter(block, initVec).
XORKeyStream(data, data)
} else {
cipher.NewCFBDecrypter(block, initVec).
XORKeyStream(data, data)
}
return nil
}
func AesDecryptData(data, key []byte, ctp string) []byte {
block, err := aes.NewCipher(key)
if err != nil {
return nil
}
if len(data) < aes.BlockSize {
return nil
}
iv := data[:aes.BlockSize]
data_dec := data[aes.BlockSize:]
var stream cipher.Stream
switch ctp {
case "cfb":
stream = cipher.NewCFBDecrypter(block, iv)
case "ctr":
stream = cipher.NewCTR(block, iv)
default:
stream = cipher.NewOFB(block, iv)
}
// XORKeyStream can work in-place if the two arguments are the same.
stream.XORKeyStream(data_dec, data_dec)
return data_dec
}
// Decrypts the given byte array.
// The function expects the given data to include the initialization vector
// within the first bytes (0 to BlockSize(16)). The remaining bytes contain the actual
// data to decrypt.
// Returns the decrypted data as byte array.
func (t *Encryption) Decrypt(data []byte) []byte {
blockSize := t.cipher.BlockSize()
decrypter := cipher.NewCFBDecrypter(t.cipher, data[0:blockSize])
ret := make([]byte, len(data)-blockSize)
decrypter.XORKeyStream(ret, data[blockSize:len(data)])
return ret
}
func AESCtyptTest() {
fmt.Println("AES测试")
//需要去加密的字符串
plaintext := []byte("My name is daniel")
//aes的加密字符串
key_text := "astaxie12798akljzmknm.ahkjkljl;k"
fmt.Println(len(key_text))
// 创建加密算法aes
c, err := aes.NewCipher([]byte(key_text))
if err != nil {
fmt.Printf("Error: NewCipher(%d bytes) = %s", len(key_text), err)
return
}
//加密字符串
cfb := cipher.NewCFBEncrypter(c, commonIV)
ciphertext := make([]byte, len(plaintext))
cfb.XORKeyStream(ciphertext, plaintext)
fmt.Printf("%s=>%x\n", plaintext, ciphertext)
// 解密字符串
cfbdec := cipher.NewCFBDecrypter(c, commonIV)
plaintextCopy := make([]byte, len(plaintext))
cfbdec.XORKeyStream(plaintextCopy, ciphertext)
fmt.Printf("%x=>%s\n", ciphertext, plaintextCopy)
}
// Coz decrypts the cryptoText with the given key.
func Coz(key string, cryptoText string) (string, error) {
k := len(key)
switch k {
default:
return "", errors.New("key length must be 16, 24 or 32")
case 16, 24, 32:
break
}
ciphertext, _ := base64.StdEncoding.DecodeString(cryptoText)
block, err := aes.NewCipher([]byte(key))
if err != nil {
return "", err
}
if len(ciphertext) < aes.BlockSize {
return "", errors.New("ciphertext too short")
}
iv := ciphertext[:aes.BlockSize]
ciphertext = ciphertext[aes.BlockSize:]
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(ciphertext, ciphertext)
return fmt.Sprintf("%s", ciphertext), nil
}
func decryptAES(src, key, privParam []byte, engineBoots, engineTime int32) (
dst []byte, err error) {
if len(privParam) != 8 {
err = ArgumentError{
Value: len(privParam),
Message: "Invalid AES PrivParameter length",
}
return
}
block, err := aes.NewCipher(key[:16])
if err != nil {
return
}
var buf bytes.Buffer
binary.Write(&buf, binary.BigEndian, engineBoots)
binary.Write(&buf, binary.BigEndian, engineTime)
iv := append(buf.Bytes(), privParam...)
dst = make([]byte, len(src))
mode := cipher.NewCFBDecrypter(block, iv)
mode.XORKeyStream(dst, src)
return
}
// DecryptToken takes the base64-encoding of an encrypted session token
// and attempts to decrypt it into the clear-text token originally encrypted,
// which is typically generated by MakeUserFormTokenText.
func DecryptToken(session_token_b64 string,key []byte) (string,error) {
// prepare the key
block, block_err := aes.NewCipher(key)
if block_err != nil {
return "",block_err
}
// take the base64-encoded encrypted token and decode it to bytes
session_token_b64_bytes,decode_token_b64_bytes_err := base64.StdEncoding.DecodeString(session_token_b64)
if decode_token_b64_bytes_err != nil {
return "",decode_token_b64_bytes_err
}
// validate and decrypt with our key
if len(session_token_b64_bytes) < aes.BlockSize {
return "",errors.New("session token bytes too short")
}
// get iv
iv := session_token_b64_bytes[:aes.BlockSize]
session_token_b64_bytes = session_token_b64_bytes[aes.BlockSize:]
cfb := cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(session_token_b64_bytes,session_token_b64_bytes)
// now we have a decrypted string which was also base64 encoded. decode that to bytes.
decrypted_session_token_bytes,decode_token_str_err :=
base64.StdEncoding.DecodeString(string(session_token_b64_bytes))
if decode_token_str_err != nil {
return "",decode_token_str_err
}
// return the string representation of the decrypted bytes
return string(decrypted_session_token_bytes),nil
}