Decode a KMS value using a specific key

decode_kms.py

import base64
import boto3
import os

encoded = os.environ.get("ENCODED")
key_arn = os.environ.get("KEY")
profile = os.environ.get("PROFILE")

if key_arn is None or encoded is None:
    raise Exception("You must provide a key & encoded values!")

session = boto3.session.Session(profile_name=profile)
kms = session.client("kms")
meta = kms.decrypt(
    KeyId=key_arn,
    CiphertextBlob=base64.b64decode(encoded)
)
plaintext = meta["Plaintext"]
print(plaintext.decode())