// AES256CBCDecrypt decrypts the given ciphertext with AES-256 in CBC mode and
// returns the resulting plaintext. The supplied key must be 32 bytes long and
// the ciphertext must be prepended by the corresponding IV.
func AES256CBCDecrypt(key, ciphertext []byte) (plaintext []byte) {
if len(key) != 32 {
panic(log.Critical("cipher: AES-256 key is not 32 bytes long"))
}
block, _ := aes.NewCipher(key) // correct key length was enforced above
// 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(log.Critical("cipher: ciphertext too short"))
}
iv := ciphertext[:aes.BlockSize]
ciphertext = ciphertext[aes.BlockSize:]
plaintext = make([]byte, len(ciphertext))
// CBC mode always works in whole blocks.
if len(ciphertext)%aes.BlockSize != 0 {
panic(log.Critical("cipher: ciphertext is not a multiple of the block size"))
}
mode := cipher.NewCBCDecrypter(block, iv)
// CryptBlocks can work in-place if the two arguments are the same.
mode.CryptBlocks(plaintext, ciphertext)
return
}
// AES256CBCEncrypt encrypts the given plaintext with AES-256 in CBC mode.
// The supplied key must be 32 bytes long.
// The returned ciphertext is prepended by a randomly generated IV.
func AES256CBCEncrypt(key, plaintext []byte, rand io.Reader) (ciphertext []byte) {
if len(key) != 32 {
panic(log.Critical("cipher: AES-256 key is not 32 bytes long"))
}
block, _ := aes.NewCipher(key) // correct key length was enforced above
// CBC mode works on blocks so plaintexts may need to be padded to the
// next whole block. For an example of such padding, see
// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. Here we'll
// assume that the plaintext is already of the correct length.
if len(plaintext)%aes.BlockSize != 0 {
panic(log.Critical("cipher: plaintext is not a multiple of the block size"))
}
// 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]
_, err := io.ReadFull(rand, iv)
if err != nil {
panic(log.Critical(err))
}
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)
return
}
// AES256CTRStream creates a new AES-256 stream in CTR mode.
// The supplied key must be 32 bytes long and the iv 16 bytes.
func AES256CTRStream(key, iv []byte) cipher.Stream {
if len(key) != 32 {
panic(log.Critical("cipher: AES-256 key is not 32 bytes long"))
}
if len(iv) != 16 {
panic(log.Critical("cipher: AES-256 IV is not 16 bytes long"))
}
block, _ := aes.NewCipher(key) // correct key length was enforced above
return cipher.NewCTR(block, iv)
}
// This example shows when and how to use the critical log level.
func Example_critical() {
alwaysFalseCondition := false
// ...
if alwaysFalseCondition {
panic(log.Critical("package name: this condition should never be true"))
}
}
// RandPass returns a random 256-bit password in base64 encoding.
func RandPass(rand io.Reader) string {
var pass = make([]byte, 32)
if _, err := io.ReadFull(rand, pass); err != nil {
panic(log.Critical(err))
}
return base64.Encode(pass)
}
// Domain returns the domain of the uid identity.
func (msg *Message) Domain() string {
_, domain, err := identity.Split(msg.UIDContent.IDENTITY)
if err != nil {
// UID messages have to be valid
panic(log.Critical(err))
}
return domain
}
// Localpart returns the localpart of the uid identity.
func (msg *Message) Localpart() string {
lp, _, err := identity.Split(msg.UIDContent.IDENTITY)
if err != nil {
// UID messages have to be valid
panic(log.Critical(err))
}
return lp
}
// ToUint16 converts the byte slice b of length 2 to an uint16.
// If b does not have length 2 the function panics.
func ToUint16(b []byte) (u uint16) {
if len(b) != 2 {
panic(log.Critical("encode: ToUint16(): len(b) != 2"))
}
u = uint16(b[1])<<8 |
uint16(b[0])
return
}
// Nonce generates a random nonce.
func Nonce(rand io.Reader) []byte {
var b = make([]byte, 8)
_, err := io.ReadFull(rand, b)
if err != nil {
panic(log.Critical(err))
}
return b
}
func (ce *CtrlEngine) getID(c *cli.Context) string {
id := c.String("id")
if id == "" && interactive {
active, err := ce.msgDB.GetValue(msgdb.ActiveUID)
if err != nil {
panic(log.Critical(err))
}
id = active
}
return id
}
// AES256CTREncrypt encrypts the given plaintext with AES-256 in CTR mode.
// The supplied key must be 32 bytes long.
// The returned ciphertext is prepended by a randomly generated IV.
func AES256CTREncrypt(key, plaintext []byte, rand io.Reader) (ciphertext []byte) {
if len(key) != 32 {
panic(log.Critical("cipher: AES-256 key is not 32 bytes long"))
}
block, _ := aes.NewCipher(key) // correct key length was enforced above
// 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]
_, err := io.ReadFull(rand, iv)
if err != nil {
panic(log.Critical(err))
}
stream := cipher.NewCTR(block, iv)
stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
return
}
// AES256CTRDecrypt decrypts the given ciphertext with AES-256 in CTR mode and
// returns the resulting plaintext. The supplied key must be 32 bytes long and
// the ciphertext must be prepended by the corresponding IV.
func AES256CTRDecrypt(key, ciphertext []byte) (plaintext []byte) {
if len(key) != 32 {
panic(log.Critical("cipher: AES-256 key is not 32 bytes long"))
}
block, _ := aes.NewCipher(key) // correct key length was enforced above
// 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(log.Critical("cipher: ciphertext too short"))
}
iv := ciphertext[:aes.BlockSize]
ciphertext = ciphertext[aes.BlockSize:]
plaintext = make([]byte, len(ciphertext))
stream := cipher.NewCTR(block, iv)
stream.XORKeyStream(plaintext, ciphertext)
return
}
// HasSession implements corresponding method for msg.KeyStore interface.
func (ce *CryptEngine) HasSession(sessionKey string) bool {
_, _, _, err := ce.keyDB.GetSession(sessionKey)
switch {
case err == sql.ErrNoRows:
return false
case err != nil:
// TODO: handle this without panic!
panic(log.Critical(err))
}
return true
}
func marshalSorted(strct interface{}) []byte {
// convert the struct to map before the JSON encoding, because maps are
// automatically sorted and structs are not
m := structs.Map(strct)
jsn, err := json.Marshal(m)
if err != nil {
// There should be not way this can happen, but better less than 100%
// test coverage than an uncaught error.
panic(log.Critical(err))
}
return jsn
}
// ToUint64 converts the byte slice b of length 8 to an uint64.
// If b does not have length 8 the function panics.
func ToUint64(b []byte) (u uint64) {
if len(b) != 8 {
panic(log.Critical("encode: ToUint64(): len(b) != 8"))
}
u = uint64(b[7])<<56 |
uint64(b[6])<<48 |
uint64(b[5])<<40 |
uint64(b[4])<<32 |
uint64(b[3])<<24 |
uint64(b[2])<<16 |
uint64(b[1])<<8 |
uint64(b[0])
return
}
