pycryptodome on Lambda using SAM

app.py

from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
import binascii
import base64

DEFAULT_MESSAGE = b'my test essage'

def createKeys():
    return RSA.generate(1024)

def encrypt(msg, pubKey):
    encryptor = PKCS1_OAEP.new(pubKey)
    return encryptor.encrypt(msg)

def decrypt(encrypted, keyPair):
    decryptor = PKCS1_OAEP.new(keyPair)
    return decryptor.decrypt(encrypted)

def lambda_handler(event, context):
    message = event.get("message", DEFAULT_MESSAGE)
    print(message)
    
    keyPair = createKeys()
    pubKey = keyPair.publickey()
    encrypted = encrypt(message, pubKey)
    decrypted = decrypt(encrypted, keyPair)

    return {
        "statusCode": 200,
        "body": {
            "message": message,
            "encrypted": base64.b64encode(encrypted),
            "decrypted": decrypted
        },
    }

file structure

$ tree .
.
├── README.md
├── hello_world
│   ├── app.py
│   └── requirements.txt
├── samconfig.toml
└── template.yaml

requirements.txt

pycryptodome

samconfig.toml

version = 0.1
[default]
[default.deploy]
[default.build.parameters]
use_container = true

template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  pycryptodome-lambda

  Sample SAM Template for pycryptodome-lambda

# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Timeout: 3

Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: hello_world/
      Handler: app.lambda_handler
      Runtime: python3.8