README
¶
Cipher Functions
This package implements the cipher functions specified in the noise protocol framework.
Built-in Ciphers
Two cipher functions are supported, as specified in the noise specs.
-
AESGCM is implemented based upon the official Go cipher package
crypto/aes. Use it with caution though, as the AES operations in thecrypto/aespackage are not implemented using constant-time algorithms, which makes it vunerable to side channel attack.However, if the package is running on systems with hardware support for AES then it won't be an issue. More details can be found following this discussion.
As for this package, AESGCM is tuned based on the noise specs:
AES256 with GCM with a 128-bit tag appended to the ciphertext. The 96-bit nonce is formed by encoding 32 bits of zeros followed by big-endian encoding of n.
-
ChaChaPoly is implemented based on
golang.org/x/crypto/chacha20poly1305by using the ChaCha20-Poly1305 AEAD.
Customized Cipher Functions
To create your own cipher function, you'll need to implement the interface specified in cipher.go. Once implemented, you need to register it using Register(Name, Cipher).
Check examples/newcipher, which implements ChaChaPolyX, once implemented, Once implemented, it can be used via the protocol name,
// Register it for package babble.
noiseCipher.Register("ChaChaPolyX", newCipher)
// Now "ChaChaPolyX" is a valid hash name, and it can be used in the protocol name as,
p, _ := babble.NewProtocol("Noise_NN_25519_ChaChaPolyX_BLAKE2s", "Demo", true)
Documentation
¶
Overview ¶
Package cipher implements the cipher functions specified in the noise protocol.
It currently supports two ciphers:
- ChaCha20Poly1350, which uses https://golang.org/x/crypto/chacha20poly1305.
- AESGCM, which uses https://pkg.go.dev/crypto/aes. Be cautious when using this cipher as it might be vunlerable to side channel attack.
Index ¶
Examples ¶
Constants ¶
const ( // KeySize defines the size of the cipher key, in bytes. KeySize = 32 // MaxNonce is an 8-byte unsigned integer and equals to 2^64-1. MaxNonce = ^uint64(0) )
Variables ¶
Functions ¶
func SupportedCiphers ¶
func SupportedCiphers() string
SupportedCiphers gives the names of all the ciphers registered. If no new ciphers are registered, it returns a string as "AESGCM, ChaChaPoly", orders not preserved.
Types ¶
type AEAD ¶
type AEAD interface {
fmt.Stringer
// Cipher returns a cipher.AEAD. This function enforces that any cipher
// implement this AEAD interface must also satisfy the cipher.AEAD.
Cipher() cipher.AEAD
// Decrypt uses a cipher key k of 32 bytes, an 8-byte unsigned integer nonce
// n, and associated data ad, and returns the plaintext, unless
// authentication fails, in which case an error is returned.
Decrypt(n uint64, ad, ciphertext []byte) ([]byte, error)
// EncodeNonce turns the nonce used in the noise protocol into a format
// that's accepted by the specific cipher specs.
EncodeNonce(n uint64) []byte
// Encrypt uses the cipher key k of 32 bytes and an 8-byte unsigned integer
// nonce n which must be unique for the key k, and returns the ciphertext.
// Encryption must be done with an "AEAD" encryption mode with the
// associated data ad and returns a ciphertext that is the same size as the
// plaintext plus 16 bytes for authentication data.
Encrypt(n uint64, ad, plaintext []byte) ([]byte, error)
// InitCipher creates a cipher with the secret key.
InitCipher(key [KeySize]byte) error
// Rekey creates a new 32-byte cipher key as a pseudorandom function of key.
// It returns the first 32 bytes from calling Encrypt with,
// - n as maxnonce, which equals 2^64-1,
// - ad as zerolen, a zero-length byte sequence,
// - plaintext as zeros, a sequence of 32 bytes filled with zeros.
Rekey() [KeySize]byte
// Reset cleans all the states to zero value, if any.
Reset()
}
AEAD specifies an interface for building a cipher used by the babbel package.
func FromString ¶
FromString uses the provided cipher name, s, to query a built-in cipher.
Example ¶
package main
import (
"fmt"
"github.com/yyforyongyu/babble/cipher"
)
func main() {
// load cipher AESGCM
aesgcm, _ := cipher.FromString("AESGCM")
fmt.Println(aesgcm)
// load cipher ChaChaPoly
ccp, _ := cipher.FromString("ChaChaPoly")
fmt.Println(ccp)
}
Output:
Source Files