To develop a Python script that displays a menu for users to select a new encryption key from a list of available keys, you can use the AWS SDK for Python (Boto3). Below is an example script that demonstrates this [1][2]:

import boto3

# Initialize the AWS KMS client
kms = boto3.client('kms')

def list_encryption_keys():
    try:
        # List the available KMS keys
        response = kms.list_keys()

        keys = response['Keys']
        if not keys:
            print("No encryption keys found.")
        else:
            print("Available Encryption Keys:")
            for index, key in enumerate(keys, start=1):
                key_id = key['KeyId']
                description = key.get('Description', 'No description available')
                print(f"{index}. Key ID: {key_id}, Description: {description}")
    except Exception as e:
        print(f"Error listing encryption keys: {e}")

def select_encryption_key():
    while True:
        list_encryption_keys()
        choice = input("Enter the number of the encryption key you want to select (or 'q' to quit): ")

        if choice.lower() == 'q':
            break

        try:
            index = int(choice)
            if 1 <= index <= len(keys):
                selected_key = keys[index - 1]
                key_id = selected_key['KeyId']
                description = selected_key.get('Description', 'No description available')
                print(f"Selected Key ID: {key_id}, Description: {description}")
                return key_id
            else:
                print("Invalid selection. Please enter a valid number.")
        except ValueError:
            print("Invalid input. Please enter a number.")

if __name__ == '__main__':
    keys = []  # Store the retrieved encryption keys
    while True:
        key_id = select_encryption_key()
        if key_id:
            break

Before running this script, make sure you have the AWS CLI configured with your AWS access and secret keys using aws configure.
This script uses Boto3 to retrieve the list of available encryption keys and allows users to select a key interactively by entering the corresponding number. It provides a simple and dynamic way for users to make a secure choice among the available keys.