diff --git a/Dockerfile b/Dockerfile
index fa0ad6338..9a225af5b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,8 +3,7 @@ ENV DOMAIN=localhost
 RUN apt-get update && \
     apt-get -y install \
     imagemagick \
-    python3-crypto \
-    python3-pycryptodome \
+    python3-cryptography \
     python3-dateutil \
     python3-idna \
     python3-requests \
diff --git a/README.md b/README.md
index bcf442eed..8a0afc7c5 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ You will need python version 3.7 or later.
 On Arch/Parabola:
 
 ``` bash
-sudo pacman -S tor python-pip python-pysocks python-pycryptodome \
+sudo pacman -S tor python-pip python-pysocks python-cryptography \
                imagemagick python-requests \
 	       perl-image-exiftool python-dateutil \
 	       certbot flake8 bandit
@@ -36,7 +36,7 @@ Or on Debian:
 sudo apt install -y \
     tor python3-socks imagemagick \
     python3-setuptools \
-    python3-crypto python3-pycryptodome \
+    python3-crypto python3-cryptography \
     python3-dateutil \
     python3-idna python3-requests \
     python3-django-timezone-field \
diff --git a/deploy/i2p b/deploy/i2p
index 2afeb74ab..79e5d7b7b 100755
--- a/deploy/i2p
+++ b/deploy/i2p
@@ -60,7 +60,7 @@ fi
 echo 'Adding Epicyon dependencies'
 if [ -f /usr/bin/pacman ]; then
     pacman -Syy
-    pacman -S --noconfirm python-pip python-pysocks python-pycryptodome \
+    pacman -S --noconfirm python-pip python-pysocks python-cryptography \
            imagemagick python-pillow python-requests \
 	   perl-image-exiftool python-numpy python-dateutil \
 	   certbot flake8 git i2pd wget qrencode \
@@ -68,7 +68,7 @@ if [ -f /usr/bin/pacman ]; then
     pip3 install pyLD pyqrcode pypng
 else
     apt-get update
-    apt-get -y install imagemagick python3-crypto python3-pycryptodome \
+    apt-get -y install imagemagick python3-crypto python3-cryptography \
 	    python3-dateutil python3-idna python3-requests \
 	    python3-numpy python3-pil.imagetk python3-pip \
 	    python3-setuptools python3-socks python3-idna \
diff --git a/deploy/onion b/deploy/onion
index ea99ffea4..983866db6 100755
--- a/deploy/onion
+++ b/deploy/onion
@@ -35,14 +35,14 @@ EPICYON_PORT=7157
 echo 'Adding Epicyon dependencies'
 if [ -f /usr/bin/pacman ]; then
     pacman -Syy
-    pacman -S --noconfirm tor python-pip python-pysocks python-pycryptodome \
+    pacman -S --noconfirm tor python-pip python-pysocks python-cryptography \
            imagemagick python-pillow python-requests \
            perl-image-exiftool python-numpy python-dateutil \
            certbot flake8 git qrencode bandit
     pip3 install pyLD pyqrcode pypng
 else
     apt-get update
-    apt-get -y install imagemagick python3-crypto python3-pycryptodome \
+    apt-get -y install imagemagick python3-crypto python3-cryptography \
             python3-dateutil python3-idna python3-requests \
             python3-numpy python3-pil.imagetk python3-pip \
             python3-setuptools python3-socks python3-idna \
diff --git a/gemini/EN/install.gmi b/gemini/EN/install.gmi
index 49dfaec68..35a28dba9 100644
--- a/gemini/EN/install.gmi
+++ b/gemini/EN/install.gmi
@@ -4,7 +4,7 @@ You will need python version 3.7 or later.
 
 On a Debian based system:
 
-    sudo apt install -y tor python3-socks imagemagick python3-setuptools python3-crypto python3-pycryptodome python3-dateutil python3-idna python3-requests python3-flake8 python3-django-timezone-field python3-pyqrcode python3-png python3-bandit libimage-exiftool-perl certbot nginx wget
+    sudo apt install -y tor python3-socks imagemagick python3-setuptools python3-crypto python3-cryptography python3-dateutil python3-idna python3-requests python3-flake8 python3-django-timezone-field python3-pyqrcode python3-png python3-bandit libimage-exiftool-perl certbot nginx wget
 
 The following instructions install Epicyon to the /opt directory. It's not essential that it be installed there, and it could be in any other preferred directory.
 
diff --git a/httpsig.py b/httpsig.py
index 443cd9a2c..a1d852284 100644
--- a/httpsig.py
+++ b/httpsig.py
@@ -1,4 +1,4 @@
-__filename__ = "posts.py"
+__filename__ = "httpsig.py"
 __author__ = "Bob Mottram"
 __credits__ = ['lamia']
 __license__ = "AGPL3+"
@@ -9,26 +9,28 @@ __status__ = "Production"
 
 # see https://tools.ietf.org/html/draft-cavage-http-signatures-06
 
-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
-
+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
+from cryptography.hazmat.primitives.asymmetric import utils as hazutils
 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')
-    digestStr = SHA256.new(msg).digest()
-    return base64.b64encode(digestStr).decode('utf-8')
+    hashResult = _getSHA256(msg)
+    return base64.b64encode(hashResult).decode('utf-8')
 
 
 def signPostHeaders(dateStr: str, privateKeyPem: str,
@@ -66,7 +68,8 @@ def signPostHeaders(dateStr: str, privateKeyPem: str,
             'content-type': 'application/activity+json',
             'content-length': str(contentLength)
         }
-    privateKeyPem = RSA.import_key(privateKeyPem)
+    key = load_pem_private_key(privateKeyPem.encode('utf-8'),
+                               None, backend=default_backend())
     # headers.update({
     #     '(request-target)': f'post {path}',
     # })
@@ -76,10 +79,14 @@ def signPostHeaders(dateStr: str, privateKeyPem: str,
     for headerKey in signedHeaderKeys:
         signedHeaderText += f'{headerKey}: {headers[headerKey]}\n'
     signedHeaderText = signedHeaderText.strip()
-    headerDigest = SHA256.new(signedHeaderText.encode('ascii'))
+    # signedHeaderText.encode('ascii') matches
+    headerDigest = _getSHA256(signedHeaderText.encode('ascii'))
+    # print('headerDigest2: ' + str(headerDigest))
 
     # Sign the digest
-    rawSignature = pkcs1_15.new(privateKeyPem).sign(headerDigest)
+    rawSignature = key.sign(headerDigest,
+                            padding.PKCS1v15(),
+                            hazutils.Prehashed(hashes.SHA256()))
     signature = base64.b64encode(rawSignature).decode('ascii')
 
     # Put it into a valid HTTP signature format
@@ -176,7 +183,8 @@ def verifyPostHeaders(httpPrefix: str, publicKeyPem: str, headers: dict,
     if debug:
         print('DEBUG: verifyPostHeaders ' + method)
 
-    publicKeyPem = RSA.import_key(publicKeyPem)
+    pubkey = load_pem_public_key(publicKeyPem.encode('utf-8'),
+                                 backend=default_backend())
     # Build a dictionary of the signature values
     signatureHeader = headers['signature']
     signatureDict = {
@@ -244,16 +252,19 @@ 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 = SHA256.new(signedHeaderText.encode('ascii'))
+    headerDigest = _getSHA256(signedHeaderText.encode('ascii'))
 
     # Get the signature, verify with public key, return result
     signature = base64.b64decode(signatureDict['signature'])
 
     try:
-        pubKey = pkcs1_15.new(publicKeyPem)
-        pubKey.verify(headerDigest, signature)
+        pubkey.verify(
+            signature,
+            headerDigest,
+            padding.PKCS1v15(),
+            hazutils.Prehashed(hashes.SHA256()))
         return True
-    except (ValueError, TypeError):
+    except BaseException:
         if debug:
             print('DEBUG: verifyPostHeaders pkcs1_15 verify failure')
         return False
diff --git a/setup.cfg b/setup.cfg
index f7985ac16..3f3e838ff 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -29,7 +29,7 @@ install_requires =
   idna >= 2.5, < 3
   numpy >= 1.20.0, < 2
   pillow >= 8.1.0, < 9
-  pycryptodome >= 3.9.9, < 4
+  cryptography
   pyqrcode >= 1.2.1, < 2
   python-dateutil >= 2.8.1, < 3
   requests >= 2.25.1, < 3
diff --git a/website/EN/index.html b/website/EN/index.html
index 39a8b3af8..ea28c162b 100644
--- a/website/EN/index.html
+++ b/website/EN/index.html
@@ -1267,7 +1267,7 @@
     <p class="intro">You will need python version 3.7 or later.</p>
     <p class="intro">On a Debian based system:</p>
     <div class="shell">
-      <p>sudo apt install -y tor python3-socks imagemagick python3-setuptools python3-crypto python3-pycryptodome python3-dateutil python3-idna python3-requests python3-flake8 python3-django-timezone-field python3-pyqrcode python3-png python3-bandit libimage-exiftool-perl certbot nginx wget</p>
+      <p>sudo apt install -y tor python3-socks imagemagick python3-setuptools python3-crypto python3-cryptography python3-dateutil python3-idna python3-requests python3-flake8 python3-django-timezone-field python3-pyqrcode python3-png python3-bandit libimage-exiftool-perl certbot nginx wget</p>
     </div>
 
     <p class="intro">