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import hashlib
from Crypto.Cipher import AES
from Crypto.PublicKey import RSA
from Crypto.Random import get_random_bytes
import libs.gmpy2_pkcs10aep_cipher as gmpy2_pkcs10aep_cipher
from extensions.ext_redis import redis_client
from extensions.ext_storage import storage
def generate_key_pair(tenant_id):
private_key = RSA.generate(2048)
public_key = private_key.publickey()
pem_private = private_key.export_key()
pem_public = public_key.export_key()
filepath = "privkeys/{tenant_id}".format(tenant_id=tenant_id) + "/private.pem"
storage.save(filepath, pem_private)
return pem_public.decode()
prefix_hybrid = b"HYBRID:"
def encrypt(text, public_key):
if isinstance(public_key, str):
public_key = public_key.encode()
aes_key = get_random_bytes(16)
cipher_aes = AES.new(aes_key, AES.MODE_EAX)
ciphertext, tag = cipher_aes.encrypt_and_digest(text.encode())
rsa_key = RSA.import_key(public_key)
cipher_rsa = gmpy2_pkcs10aep_cipher.new(rsa_key)
enc_aes_key = cipher_rsa.encrypt(aes_key)
encrypted_data = enc_aes_key + cipher_aes.nonce + tag + ciphertext
return prefix_hybrid + encrypted_data
def get_decrypt_decoding(tenant_id):
filepath = "privkeys/{tenant_id}".format(tenant_id=tenant_id) + "/private.pem"
cache_key = 'tenant_privkey:{hash}'.format(hash=hashlib.sha3_256(filepath.encode()).hexdigest())
private_key = redis_client.get(cache_key)
if not private_key:
try:
private_key = storage.load(filepath)
except FileNotFoundError:
raise PrivkeyNotFoundError("Private key not found, tenant_id: {tenant_id}".format(tenant_id=tenant_id))
redis_client.setex(cache_key, 120, private_key)
rsa_key = RSA.import_key(private_key)
cipher_rsa = gmpy2_pkcs10aep_cipher.new(rsa_key)
return rsa_key, cipher_rsa
def decrypt_token_with_decoding(encrypted_text, rsa_key, cipher_rsa):
if encrypted_text.startswith(prefix_hybrid):
encrypted_text = encrypted_text[len(prefix_hybrid):]
enc_aes_key = encrypted_text[:rsa_key.size_in_bytes()]
nonce = encrypted_text[rsa_key.size_in_bytes():rsa_key.size_in_bytes() + 16]
tag = encrypted_text[rsa_key.size_in_bytes() + 16:rsa_key.size_in_bytes() + 32]
ciphertext = encrypted_text[rsa_key.size_in_bytes() + 32:]
aes_key = cipher_rsa.decrypt(enc_aes_key)
cipher_aes = AES.new(aes_key, AES.MODE_EAX, nonce=nonce)
decrypted_text = cipher_aes.decrypt_and_verify(ciphertext, tag)
else:
decrypted_text = cipher_rsa.decrypt(encrypted_text)
return decrypted_text.decode()
def decrypt(encrypted_text, tenant_id):
rsa_key, cipher_rsa = get_decrypt_decoding(tenant_id)
return decrypt_token_with_decoding(encrypted_text, rsa_key, cipher_rsa)
class PrivkeyNotFoundError(Exception):
pass
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