How to encrypt and decrypt using AWS KMS key in python with boto3

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Python | Encrypt and Decrypt using AWS KMS key in python with boto3

This is an example of how to encrypt and decrypt a text using the AWS KMS key. In this, we will use encrypt() and decrypt() function to encrypt and decrypt any text.

These are some necessary items that let you do the encrypt and decrypt

import boto3

KEY_ID = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'
AWS_ACCESS_KEY_ID = 'some-access-key-id'
AWS_SECRET_ACCESS_KEY = 'some-aws-secret-access-key'
REGION_NAME = 'eu-west-1'

Now creating a botocore.client.KMS object

kms_client = boto3.client(
    'kms',
    aws_access_key_id=AWS_ACCESS_KEY_ID,
    aws_secret_access_key=AWS_SECRET_ACCESS_KEY,
    region_name=REGION_NAME
)

let's check kms_client

print(kms_client)
#Output: <botocore.client.KMS object at 0x000001A673B08438>

print(type(kms_client))
#Output: <class 'botocore.client.KMS'>

Encryption

Now with the help of encrypt() function, we will encrypt a text. It will return a dictionary having encrypted data in CiphertextBlob

data = kms_client.encrypt(
                KeyId=KEY_ID,
                Plaintext='hello!',
                EncryptionAlgorithm='SYMMETRIC_DEFAULT'
            )

Let's check the data

print(data)

'''
Output :

{
    'CiphertextBlob': b'\x01\x02\x02\x00x\xce?&4\x96t\x05J\xc8\x1a_\x000M\x06\t*\x86H\x86\xf7\xd5B\xdd\x198\xa7\x8e\x12-\xab\xae\xef\xd6jFI\x01_)IU\xd1\xe8zs\xce\xfa\x00\x91\x95\x00`\x07=\x00\x00c0a\x06\t*\x86H\x86\xf7\r\x01\x07\x06\xa0T0R\x02\x01\r\x01\x07\x010\x1eee\x06\t`\x86H\x01e\x03\x04\x01.0\x11\x04\x0cbI#\xa6\x9a&\xd6x\xf7\x16u\xa6\x02\x01\x10\x80\x000M\x06\t*\x86H\x86\xf7 \x97\x10e\x05\x05\x1d\xba\x96\xf6\x9f\x8e\x8b\xedU\r&2u\xaf%!\x000M\x06\t*\x86H\x86\xf7xfb\xbf\xa1',
    'KeyId': 'arn:aws:kms:eu-west-1:444444444444:key/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx',
    'EncryptionAlgorithm': 'SYMMETRIC_DEFAULT',
    'ResponseMetadata': {
        'RequestId': '22b6022a-3cca-4444-a333-0a621b99fa39',
        'HTTPStatusCode': 200,
        'HTTPHeaders': {
            'x-amzn-requestid': '22b6022a-3cca-4444-a333-0a621b99fa39',
            'cache-control': 'no-cache, no-store, must-revalidate, private',
            'expires': '0',
            'pragma': 'no-cache',
            'date': 'Tue, 13 Apr 2020 08:11:41 GMT',
            'content-type': 'application/x-amz-json-1.1',
            'content-length': '361'
        },
        'RetryAttempts': 0}
}
'''

Now encode the encrypted data with base64

encoded_data = base64.b64encode(data['CiphertextBlob'])
print(encoded_data)
# Output
#b'AQICAHjImd0bXTPOPyY0lnQFShpf1kgBZQMEAS4wEQQMVe6DULdGTinjhItq67v1mpGSQEptPmGwQ60v0i03Us/NGc4AAAAYzBhBgkqhkiG9w0BBwag6z26cZ0HNnAxKWBVDBSAgEAME0GCSqGSIb3DQEHATAeBglgh9yqP4or8B2I4AgEQgCCKgZAgnYVqV9XqfTSAl/2BWWGHU+w=='

Decryption

now lets decrypt the encrypted data using decrypt() function. It takes the encrypted CiphertextBlob data and returns the plaintext. As the encrypted data is encoded with base64, so it is required to decode the encoded text before passing it to the decrypt() function.

decrypted_data= kms_client.decrypt(CiphertextBlob=base64.b64decode(encoded_data))

let's check decrypted_data

print(decrypted_data)

'''
Output :
{
    'KeyId': 'arn:aws:kms:eu-west-1:444444444444:key/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx',
    'Plaintext': b'hello!',
    'EncryptionAlgorithm': 'SYMMETRIC_DEFAULT',
    'ResponseMetadata': {
        'RequestId': '11f000da-44e9-999b-8a80-289dc4a88888',
        'HTTPStatusCode': 200,
        'HTTPHeaders': {
            'x-amzn-requestid': '11f000da-44e9-999b-8a80-289dc4a88888',
            'cache-control': 'no-cache, no-store, must-revalidate, private',
            'expires': '0',
            'pragma': 'no-cache',
            'date': 'Tue, 13 Apr 2020 08:30:45 GMT',
            'content-type': 'application/x-amz-json-1.1',
            'content-length': '152'
        },
        'RetryAttempts': 0
    }
}
'''

Get the plain text only

print(decrypted_data['Plaintext'])

# Output: b'hello!'

 

Tips and Tricks


What is pass in Python?

Python | Pass Statement

The pass statement is used as a placeholder for future code. It represents a null operation in Python. It is generally used for the purpose of filling up empty blocks of code which may execute during runtime but has yet to be written.

 

def myfunction():
    pass

 


How can you generate random numbers?

Python | Generate random numbers

Python provides a module called random using which we can generate random numbers. e.g: print(random.random())

 

 

We have to import a random module and call the random() method as shown below:

 import random

 print(random.random())

The random() method generates float values lying between 0 and 1 randomly.


To generate customized random numbers between specified ranges, we can use the randrange() method
Syntax: randrange(beginning, end, step)
 

import random

print(random.randrange(5,100,2))

 


What is lambda in Python?

Python | Lambda function

A lambda function is a small anonymous function. This function can have any number of parameters but, can have just one statement.
 

 

Syntex: 
lambda arguments : expression
 

a = lambda x,y : x+y

print(a(5, 6))

It also provides a nice way to write closures. With that power, you can do things like this.

def adder(x):
    return lambda y: x + y

add5 = adder(5)

add5(1)    #6

As you can see from the snippet of Python, the function adder takes in an argument x and returns an anonymous function, or lambda, that takes another argument y. That anonymous function allows you to create functions from functions. This is a simple example, but it should convey the power lambdas and closures have.
 


What is swapcase() function in the Python?

Python | swapcase() Function

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string = "IT IS IN LOWERCASE."  

print(string.swapcase())  

 


How to remove whitespaces from a string in Python?

Python | strip() Function | Remove whitespaces from a string 

To remove the whitespaces and trailing spaces from the string, Python provides a strip([str]) built-in function. This function returns a copy of the string after removing whitespaces if present. Otherwise returns the original string.
 

string = "  Python " 
 
print(string.strip())  

 


What is the usage of enumerate() function in Python?

Python | enumerate() Function

The enumerate() function is used to iterate through the sequence and retrieve the index position and its corresponding value at the same time.
 

lst = ["A","B","C"] 
 
print (list(enumerate(lst)))

#[(0, 'A'), (1, 'B'), (2, 'C')]

 


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Python | filter(), map(), and reduce() Functions

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>>> from collections import namedtuple

#format
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#declaring the tuple
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>>> Chris.Chemistry
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We can use the Counter method from the collections module

from collections import Counter

dict1 = {'a': 5, 'b': 3, 'c': 2}
dict2 = {'a': 2, 'b': 4, 'c': 3}

new_dict = Counter(dict1) + Counter(dict2)


print(new_dict)
# Print: Counter({'a': 7, 'b': 7, 'c': 5})


 


Python In-place swapping of two numbers

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>>> a, b = 10, 20
>>> print(a, b)
10 20

>>> a, b = b, a
>>> print(a, b)
20 10

 


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Python | Reversing a String

>>> x = 'PythonWorld'
>>> print(x[: : -1])
dlroWnohtyP

 


Python join all items of a list to convert into a single string

Python | Join all items of a list to convert into a single string

>>> x = ["Python", "Online", "Training"]
>>> print(" ".join(x))
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Python | Return multiple values from functions

>>> def A():
	return 2, 3, 4

>>> a, b, c = A()

>>> print(a, b, c)
2 3 4

 


Python Print String N times

Python | Print String N times

>>> s = 'Python'
>>> n = 5

>>> print(s * n)
PythonPythonPythonPythonPython

 


Python check the memory usage of an object

Python | Check the memory usage of  an object

>>> import sys
>>> x = 100

>>> print(sys.getsizeof(x))
28