NodeJS AWS IAM-KMS Token Encryptor and Decryptor

1/* 
2    Keyring Safe Box V0.0.1 Alpha
3    Encrypt and Decrypt keys using AWS KMS
4    http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/KMS.html
5    Requirements: aws-sdk reads in your aws credentials from ~/.aws/credentials
6
7    How to run:
8    node index encrypt --alias="twitterbot" --token="xxxxx"
9    node index decrypt --token="xxxasdasd"
10 */
11const AWS = require('aws-sdk');
12const kms = new AWS.KMS({ region: 'eu-west-1' });
13
14// Entrypoint
15const args = require('yargs')
16    .command('decrypt', 'Decrypt a token', (yargs) => { }, (argv) => {
17        const { token } = argv;
18        decrypt(token);
19    })
20    .command('encrypt', 'Encrypt a token', (yargs) => { }, (argv) => {
21        const { alias, token } = argv;
22        encrypt(token,alias);
23
24    })
25    .command('*', 'Encrypt a token', (yargs) => { }, (argv) => {
26        const { alias, token } = argv;
27        encrypt(token,alias);
28    })
29    .argv;
30
31function encrypt(plainText, alias) {
32    if(!plainText || !alias){
33        throw Error ('Missing Parameters');
34        process.exit(1);    
35    }    
36    const params = {
37        KeyId: `alias/${alias}`,
38        Plaintext: plainText
39    };
40    kms.encrypt(params).promise()
41        .then(data => {
42            const { CiphertextBlob } = data; // Base64 - binary into the ASCII character set.                       
43            const base64data = CiphertextBlob.toString('base64');
44            log(base64data)
45        })
46        .catch(err => {
47            log(err, err.stack);
48        });
49}
50
51function decrypt(cipherText) {
52    if(!cipherText){
53        throw Error ('Missing Parameters');
54        process.exit(1);    
55    }    
56    const params = {
57        CiphertextBlob: new Buffer(cipherText, 'base64')
58    };
59
60    kms.decrypt(params).promise()
61        .then(data => {
62            const { Plaintext } = data; // Base64 - binary into the ASCII character set.  
63            const decryptedText = Plaintext.toString('ascii');
64            log(decryptedText)
65        })
66        .catch(err => {
67            log(err, err.stack);
68        });
69}
70
71function log(text){
72    console.log(text);
73}