Revert "Test switching from pycryptodome to python3-cryptography"

This reverts commit bb28858c9e.

httpsig.py

@@ -9,26 +9,26 @@ __status__ = "Production"
 
 # see https://tools.ietf.org/html/draft-cavage-http-signatures-06
 
-from cryptography.hazmat.backends import default_backend
-from cryptography.hazmat.primitives.serialization import load_pem_private_key
-from cryptography.hazmat.primitives.serialization import load_pem_public_key
-from cryptography.hazmat.primitives.asymmetric import padding
-from cryptography.hazmat.primitives import hashes
+try:
+    from Cryptodome.PublicKey import RSA
+    from Cryptodome.Hash import SHA256
+    from Cryptodome.Signature import pkcs1_15
+except ImportError:
+    from Crypto.PublicKey import RSA
+    from Crypto.Hash import SHA256
+    # from Crypto.Signature import PKCS1_v1_5
+    from Crypto.Signature import pkcs1_15
+
 import base64
 from time import gmtime, strftime
 import datetime
 from utils import getFullDomain
 
 
-def _getSHA256(msg: str):
-    digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
-    digest.update(msg)
-    return digest.finalize()
-
-
 def messageContentDigest(messageBodyJsonStr: str) -> str:
     msg = messageBodyJsonStr.encode('utf-8')
-    return base64.b64encode(_getSHA256(msg)).decode('utf-8')
+    digestStr = SHA256.new(msg).digest()
+    return base64.b64encode(digestStr).decode('utf-8')
 
 
 def signPostHeaders(dateStr: str, privateKeyPem: str,
@@ -66,8 +66,7 @@ def signPostHeaders(dateStr: str, privateKeyPem: str,
             'content-type': 'application/activity+json',
             'content-length': str(contentLength)
         }
-    key = load_pem_private_key(privateKeyPem.encode('utf-8'),
-                               None, backend=default_backend())
+    privateKeyPem = RSA.import_key(privateKeyPem)
     # headers.update({
     #     '(request-target)': f'post {path}',
     # })
@@ -77,11 +76,10 @@ def signPostHeaders(dateStr: str, privateKeyPem: str,
     for headerKey in signedHeaderKeys:
         signedHeaderText += f'{headerKey}: {headers[headerKey]}\n'
     signedHeaderText = signedHeaderText.strip()
-    headerDigest = _getSHA256(signedHeaderText.encode('ascii'))
+    headerDigest = SHA256.new(signedHeaderText.encode('ascii'))
 
     # Sign the digest
-    rawSignature = key.sign(headerDigest,
-                            padding.PKCS1v15(), hashes.SHA256())
+    rawSignature = pkcs1_15.new(privateKeyPem).sign(headerDigest)
     signature = base64.b64encode(rawSignature).decode('ascii')
 
     # Put it into a valid HTTP signature format
@@ -178,8 +176,7 @@ def verifyPostHeaders(httpPrefix: str, publicKeyPem: str, headers: dict,
     if debug:
         print('DEBUG: verifyPostHeaders ' + method)
 
-    pubkey = load_pem_public_key(publicKeyPem.encode('utf-8'),
-                                 backend=default_backend())
+    publicKeyPem = RSA.import_key(publicKeyPem)
     # Build a dictionary of the signature values
     signatureHeader = headers['signature']
     signatureDict = {
@@ -247,19 +244,16 @@ def verifyPostHeaders(httpPrefix: str, publicKeyPem: str, headers: dict,
         print('DEBUG: signedHeaderList: ' + str(signedHeaderList))
     # Now we have our header data digest
     signedHeaderText = '\n'.join(signedHeaderList)
-    headerDigest = _getSHA256(signedHeaderText.encode('ascii'))
+    headerDigest = SHA256.new(signedHeaderText.encode('ascii'))
 
     # Get the signature, verify with public key, return result
     signature = base64.b64decode(signatureDict['signature'])
 
     try:
-        pubkey.verify(
-            signature,
-            headerDigest,
-            padding.PKCS1v15(),
-            hashes.SHA256())
+        pubKey = pkcs1_15.new(publicKeyPem)
+        pubKey.verify(headerDigest, signature)
         return True
-    except BaseException:
+    except (ValueError, TypeError):
         if debug:
             print('DEBUG: verifyPostHeaders pkcs1_15 verify failure')
         return False