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-rw-r--r--encrypt.py31
1 files changed, 16 insertions, 15 deletions
diff --git a/encrypt.py b/encrypt.py
index 5bc1508..162b6df 100644
--- a/encrypt.py
+++ b/encrypt.py
@@ -7,34 +7,35 @@ import struct
import subprocess
import binascii
-def encrypt_file(filename_in):
+def encrypt_file(filename_in, chunk_size=1000000//16):
file_id = secrets.token_urlsafe(22)
auth_secret = secrets.token_bytes(16)
key = secrets.token_bytes(16)
- cipher_nonce = secrets.token_bytes(8)
+ data_nonce = secrets.token_bytes(8)
token_cipher = AES.new(auth_secret, AES.MODE_GCM)
ciphertext, token_tag = token_cipher.encrypt_and_digest(key)
token = base64.b64encode(ciphertext)
- with open(f'{file_id}.enc', 'wb') as fout:
+ with open(f'{file_id}.enc', 'wb') as fout, open(filename_in, 'rb') as fin:
fout.write(token_cipher.nonce) # 16 bytes
fout.write(token_tag) # 16 bytes
fout.write(auth_secret) # 16 bytes
- fout.write(cipher_nonce) # 8 bytes
- fout.flush()
+ fout.write(data_nonce) # 8 bytes
- subprocess.check_call(['openssl', 'enc', '-aes-128-ctr',
- '-K', binascii.hexlify(key),
- '-iv', binascii.hexlify(cipher_nonce + b'\0'*8), # nonce || counter format
- '-in', filename_in, # no out: output defaults to stdout
- ], stdout=fout.fileno())
+ cipher = AES.new(key, AES.MODE_CTR,
+ initial_value=struct.pack('<Q', 0), nonce=data_nonce)
- return file_id, token
+ block = fin.read(cipher.block_size*chunk_size)
+ while block:
+ data = cipher.encrypt(block)
+ fout.write(data)
+ block = fin.read(cipher.block_size*chunk_size)
-def decrypt_generator(file_id, token, seek=0):
+ return file_id, token
- with open(f'{file_id}.enc', 'rb', buffering=8192) as fin:
+def decrypt_generator(file_id, token, seek=0, chunk_size=1000000//16):
+ with open(f'{file_id}.enc', 'rb') as fin:
token_nonce = fin.read(16)
token_tag = fin.read(16)
auth_secret = fin.read(16)
@@ -50,12 +51,12 @@ def decrypt_generator(file_id, token, seek=0):
fin.seek(seek - seek % cipher.block_size, 1)
offset = seek % cipher.block_size
- block = fin.read(cipher.block_size)
+ block = fin.read(cipher.block_size*chunk_size)
while block:
data = cipher.decrypt(block)
yield data[offset:]
offset = 0
- block = fin.read(cipher.block_size)
+ block = fin.read(cipher.block_size*chunk_size)
if __name__ == '__main__':
import argparse