forked from r4sas/PBinCLI
2 changed files with 18 additions and 163 deletions
@ -1,147 +0,0 @@
@@ -1,147 +0,0 @@
|
||||
#!/usr/bin/env python |
||||
# -*- coding: utf-8 -*- |
||||
|
||||
""" |
||||
Edited SJCL.py library (https://github.com/berlincode/sjcl/) |
||||
for AES.MODE_GCM support, work begin. |
||||
|
||||
pip3.5 install pycryptodome |
||||
""" |
||||
|
||||
from Crypto.Hash import SHA256, HMAC |
||||
from Crypto.Protocol.KDF import PBKDF2 |
||||
from Crypto.Cipher import AES |
||||
from Crypto.Random import get_random_bytes |
||||
import base64 |
||||
|
||||
|
||||
def truncate_iv(iv, ol, tlen): # ol and tlen in bits |
||||
ivl = len(iv) # iv length in bytes |
||||
ol = (ol - tlen) // 8 |
||||
|
||||
# "compute the length of the length" (see gcm.js) |
||||
L = 2 |
||||
while (L < 4) and ((ol >> (8*L))) > 0: |
||||
L += 1 |
||||
if L < 15 - ivl: |
||||
L = 15 - ivl |
||||
|
||||
return iv[:(15-L)] |
||||
|
||||
|
||||
def check_mode_gcm(): |
||||
# checks if pycrypto has support for gcm |
||||
try: |
||||
AES.MODE_GCM |
||||
except: |
||||
raise Exception( |
||||
"Pycrypto does not seem to support MODE_gcm. " + |
||||
"You need a version >= 2.7a1 (or a special branch)." |
||||
) |
||||
|
||||
|
||||
class SJCL(object): |
||||
|
||||
def __init__(self): |
||||
self.salt_size = 8 # bytes |
||||
self.tag_size = 16 # bytes |
||||
self.mac_size = 16 # bytes; mac = message authentication code (MAC) |
||||
self.prf = lambda p, s: HMAC.new(p, s, SHA256).digest() |
||||
|
||||
def decrypt(self, data, passphrase): |
||||
check_mode_gcm() # check gcm support |
||||
|
||||
if data["cipher"] != "aes": |
||||
raise Exception("only aes cipher supported") |
||||
print(data["mode"]) |
||||
if data["mode"] != "gcm": |
||||
raise Exception("unknown mode(!=gcm)") |
||||
|
||||
if data["adata"] != "": |
||||
raise Exception("additional authentication data not equal ''") |
||||
|
||||
if data["v"] != 1: |
||||
raise Exception("only version 1 is currently supported") |
||||
|
||||
if data["ts"] != self.tag_size * 8: |
||||
raise Exception("desired tag length != %d" % (self.tag_size * 8)) |
||||
|
||||
salt = base64.b64decode(data["salt"]) |
||||
|
||||
# print "salt", hex_string(salt) |
||||
if len(salt) != self.salt_size: |
||||
raise Exception("salt should be %d bytes long" % self.salt_size) |
||||
|
||||
dkLen = data["ks"] / 8 |
||||
if dkLen != 32: |
||||
raise Exception("key length should be 32 bytes") |
||||
|
||||
key = PBKDF2( |
||||
passphrase, |
||||
salt, |
||||
count=data['iter'], |
||||
dkLen=dkLen, |
||||
prf=self.prf |
||||
) |
||||
# print "key", hex_string(key) |
||||
|
||||
ciphertext = base64.b64decode(data["ct"]) |
||||
# ciphertext = data["ct"] |
||||
iv = base64.b64decode(data["iv"]) |
||||
# print AES.block_size |
||||
|
||||
nonce = truncate_iv(iv, len(ciphertext)*8, data["ts"]) |
||||
|
||||
# split tag from ciphertext (tag was simply appended to ciphertext) |
||||
mac = ciphertext[-(data["ts"] / 8):] |
||||
# print len(ciphertext) |
||||
ciphertext = ciphertext[:-(data["ts"] / 8)] |
||||
# print len(ciphertext) |
||||
# print len(tag) |
||||
|
||||
# print "len", len(nonce) |
||||
cipher = AES.new(key, AES.MODE_GCM, nonce) |
||||
plaintext = cipher.decrypt(ciphertext) |
||||
# print(mac) |
||||
# cipher.verify(mac) |
||||
|
||||
return plaintext |
||||
|
||||
def encrypt(self, plaintext, passphrase, count=10000, dkLen=32): |
||||
# dkLen = key length in bytes |
||||
|
||||
check_mode_gcm() # check gcm support |
||||
|
||||
salt = get_random_bytes(self.salt_size) |
||||
iv = get_random_bytes(16) # TODO dkLen? |
||||
|
||||
key = PBKDF2(passphrase, salt, count=count, dkLen=dkLen, prf=self.prf) |
||||
|
||||
# TODO plaintext padding? |
||||
nonce = truncate_iv(iv, len(plaintext) * 8, self.tag_size * 8) |
||||
# print len(nonce) |
||||
|
||||
cipher = AES.new( |
||||
key, |
||||
AES.MODE_GCM, |
||||
nonce, |
||||
mac_len=self.mac_size |
||||
) |
||||
|
||||
ciphertext = cipher.encrypt(plaintext) |
||||
mac = cipher.digest() |
||||
|
||||
ciphertext = ciphertext + mac |
||||
|
||||
return { |
||||
"salt": base64.b64encode(salt).decode('UTF-8'), |
||||
"iter": count, |
||||
"ks": dkLen*8, |
||||
"ct": base64.b64encode(ciphertext).decode('UTF-8'), |
||||
"iv": base64.b64encode(iv).decode('UTF-8'), |
||||
"cipher": "aes", |
||||
"mode": "gcm", |
||||
"adata": "", |
||||
"v": 1, |
||||
"ts": self.tag_size * 8 |
||||
} |
||||
Loading…
Reference in new issue