diff --git a/frappe/integrations/doctype/paytm_settings/checksum.py b/frappe/integrations/doctype/paytm_settings/checksum.py
deleted file mode 100644
index 32f976ae18..0000000000
--- a/frappe/integrations/doctype/paytm_settings/checksum.py
+++ /dev/null
@@ -1,80 +0,0 @@
-import base64
-import string
-import random
-import hashlib
-import sys
-
-from Crypto.Cipher import AES
-
-
-iv = '@@@@&&&&####$$$$'
-BLOCK_SIZE = 16
-
-if (sys.version_info > (3, 0)):
-	__pad__ = lambda s: bytes(s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * chr(BLOCK_SIZE - len(s) % BLOCK_SIZE), 'utf-8')
-else:
-	__pad__ = lambda s: s + (BLOCK_SIZE - len(s) % BLOCK_SIZE) * chr(BLOCK_SIZE - len(s) % BLOCK_SIZE)
-
-__unpad__ = lambda s: s[0:-ord(s[-1])]
-
-def encrypt(input, key):
-	input = __pad__(input)
-	c = AES.new(key.encode("utf8"), AES.MODE_CBC, iv.encode("utf8"))
-	input = c.encrypt(input)
-	input = base64.b64encode(input)
-	return input.decode("UTF-8")
-
-def decrypt(encrypted, key):
-	encrypted = base64.b64decode(encrypted)
-	c = AES.new(key.encode("utf8"), AES.MODE_CBC, iv.encode("utf8"))
-	param = c.decrypt(encrypted)
-	if type(param) == bytes:
-		param = param.decode()
-	return __unpad__(param)
-
-def generateSignature(params, key):
-	if not type(params) is dict and not type(params) is str:
-		raise Exception("string or dict expected, " + str(type(params)) + " given")
-	if type(params) is dict:
-		params = getStringByParams(params)
-	return generateSignatureByString(params, key)
-
-def verifySignature(params, key, checksum):
-	if not type(params) is dict and not type(params) is str:
-		raise Exception("string or dict expected, " + str(type(params)) + " given")
-	if "CHECKSUMHASH" in params:
-		del params["CHECKSUMHASH"]
-		
-	if type(params) is dict:
-		params = getStringByParams(params)
-	return verifySignatureByString(params, key, checksum)
-
-def generateSignatureByString(params, key):
-	salt = generateRandomString(4)
-	return calculateChecksum(params, key, salt)
-
-def verifySignatureByString(params, key, checksum):
-	paytm_hash = decrypt(checksum, key)    
-	salt = paytm_hash[-4:]
-	return paytm_hash == calculateHash(params, salt)
-
-def generateRandomString(length):
-	chars = string.ascii_uppercase + string.digits + string.ascii_lowercase
-	return ''.join(random.choice(chars) for _ in range(length))
-
-def getStringByParams(params):
-	params_string = []
-	for key in sorted(params.keys()):
-		value = params[key] if params[key] is not None and params[key].lower() != "null" else ""
-		params_string.append(str(value))
-	return '|'.join(params_string)
-
-def calculateHash(params, salt):
-	finalString = '%s|%s' % (params, salt)
-	hasher = hashlib.sha256(finalString.encode())
-	hashString = hasher.hexdigest() + salt
-	return hashString
-
-def calculateChecksum(params, key, salt): 
-	hashString = calculateHash(params, salt)
-	return encrypt(hashString, key)
\ No newline at end of file
diff --git a/frappe/integrations/doctype/paytm_settings/paytm_settings.py b/frappe/integrations/doctype/paytm_settings/paytm_settings.py
index c169a53246..bfa9b6b3eb 100644
--- a/frappe/integrations/doctype/paytm_settings/paytm_settings.py
+++ b/frappe/integrations/doctype/paytm_settings/paytm_settings.py
@@ -13,7 +13,7 @@ from frappe import _
 from frappe.utils import get_url, call_hook_method, cint, flt, cstr
 from frappe.integrations.utils import create_request_log, create_payment_gateway
 from frappe.utils import get_request_site_address
-from frappe.integrations.doctype.paytm_settings.checksum import generateSignature, verifySignature
+from paytmchecksum import generateSignature, verifySignature
 from frappe.utils.password import get_decrypted_password
 
 class PaytmSettings(Document):
diff --git a/requirements.txt b/requirements.txt
index e6f6f9fff9..d053f8f48c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -66,5 +66,5 @@ watchdog==0.8.0
 Werkzeug==0.16.1
 xlrd==1.2.0
 zxcvbn-python==4.4.24
-pycryptodome==3.9.7
 Whoosh==2.7.4
+paytmchecksum==1.7.0
\ No newline at end of file