Skip to content

Instantly share code, notes, and snippets.

@lynsei

lynsei/my-open-pgp-reference.js.md

Created February 22, 2022 15:27
Show Gist options
  • Save lynsei/3865aac5f66369b2b5a8ace447d88783 to your computer and use it in GitHub Desktop.
Save lynsei/3865aac5f66369b2b5a8ace447d88783 to your computer and use it in GitHub Desktop.
Download ZIP
[openpgp] #reference #openpgp #pgp #implementation #node #nodejs #tsc #typescript
Raw
my-open-pgp-reference.js.md

Encrypt and decrypt String data with PGP keys

Encryption will use the algorithm preferred by the public (encryption) key (defaults to aes256 for keys generated in OpenPGP.js), and decryption will use the algorithm used for encryption.

const openpgp = require('openpgp'); // use as CommonJS, AMD, ES6 module or via window.openpgp
(async () => {
    // put keys in backtick (``) to avoid errors caused by spaces or tabs
    const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`;
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with

    const publicKey = await openpgp.readKey({ armoredKey: publicKeyArmored });

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const encrypted = await openpgp.encrypt({
        message: await openpgp.createMessage({ text: 'Hello, World!' }), // input as Message object
        encryptionKeys: publicKey,
        signingKeys: privateKey // optional
    });
    console.log(encrypted); // '-----BEGIN PGP MESSAGE ... END PGP MESSAGE-----'

    const message = await openpgp.readMessage({
        armoredMessage: encrypted // parse armored message
    });
    const { data: decrypted, signatures } = await openpgp.decrypt({
        message,
        verificationKeys: publicKey, // optional
        decryptionKeys: privateKey
    });
    console.log(decrypted); // 'Hello, World!'
    // check signature validity (signed messages only)
    try {
        await signatures[0].verified; // throws on invalid signature
        console.log('Signature is valid');
    } catch (e) {
        throw new Error('Signature could not be verified: ' + e.message);
    }
})();

Encrypt to multiple public keys:

(async () => {
    const publicKeysArmored = [
        `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`,
        `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`
    ];
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`;    // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with
    const plaintext = 'Hello, World!';

    const publicKeys = await Promise.all(publicKeysArmored.map(armoredKey => openpgp.readKey({ armoredKey })));

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const message = await openpgp.createMessage({ text: plaintext });
    const encrypted = await openpgp.encrypt({
        message, // input as Message object
        encryptionKeys: publicKeys,
        signingKeys: privateKey // optional
    });
    console.log(encrypted); // '-----BEGIN PGP MESSAGE ... END PGP MESSAGE-----'
})();

If you expect an encrypted message to be signed with one of the public keys you have, and do not want to trust the decrypted data otherwise, you can pass the decryption option expectSigned = true, so that the decryption operation will fail if no valid signature is found:

(async () => {
    // put keys in backtick (``) to avoid errors caused by spaces or tabs
    const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`;
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with

    const publicKey = await openpgp.readKey({ armoredKey: publicKeyArmored });

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const encryptedAndSignedMessage = `-----BEGIN PGP MESSAGE-----
...
-----END PGP MESSAGE-----`;

    const message = await openpgp.readMessage({
        armoredMessage: encryptedAndSignedMessage // parse armored message
    });
    // decryption will fail if all signatures are invalid or missing
    const { data: decrypted, signatures } = await openpgp.decrypt({
        message,
        decryptionKeys: privateKey,
        expectSigned: true,
        verificationKeys: publicKey, // mandatory with expectSigned=true
    });
    console.log(decrypted); // 'Hello, World!'
})();

Encrypt symmetrically with compression

By default, encrypt will not use any compression when encrypting symmetrically only (i.e. when no encryptionKeys are given). It's possible to change that behaviour by enabling compression through the config, either for the single encryption:

(async () => {
    const message = await openpgp.createMessage({ binary: new Uint8Array([0x01, 0x02, 0x03]) }); // or createMessage({ text: 'string' })
    const encrypted = await openpgp.encrypt({
        message,
        passwords: ['secret stuff'], // multiple passwords possible
        config: { preferredCompressionAlgorithm: openpgp.enums.compression.zlib } // compress the data with zlib
    });
})();

or by changing the default global configuration:

openpgp.config.preferredCompressionAlgorithm = openpgp.enums.compression.zlib

Where the value can be any of:

  • openpgp.enums.compression.zip
  • openpgp.enums.compression.zlib
  • openpgp.enums.compression.uncompressed (default)

Streaming encrypt Uint8Array data with a password

(async () => {
    const readableStream = new ReadableStream({
        start(controller) {
            controller.enqueue(new Uint8Array([0x01, 0x02, 0x03]));
            controller.close();
        }
    });
    const message = await openpgp.createMessage({ binary: readableStream });
    const encrypted = await openpgp.encrypt({
        message, // input as Message object
        passwords: ['secret stuff'], // multiple passwords possible
        format: 'binary' // don't ASCII armor (for Uint8Array output)
    });
    console.log(encrypted); // raw encrypted packets as ReadableStream<Uint8Array>

    // Either pipe the above stream somewhere, pass it to another function,
    // or read it manually as follows:
    for await (const chunk of encrypted) {
        console.log('new chunk:', chunk); // Uint8Array
    }
})();

For more information on using ReadableStreams, see the MDN Documentation on the Streams API.

You can also pass a Node.js Readable stream, in which case OpenPGP.js will return a Node.js Readable stream as well, which you can .pipe() to a Writable stream, for example.

Streaming encrypt and decrypt String data with PGP keys

(async () => {
    const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`; // Public key
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // Encrypted private key
    const passphrase = `yourPassphrase`; // Password that private key is encrypted with

    const publicKey = await openpgp.readKey({ armoredKey: publicKeyArmored });

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const readableStream = new ReadableStream({
        start(controller) {
            controller.enqueue('Hello, world!');
            controller.close();
        }
    });

    const encrypted = await openpgp.encrypt({
        message: await openpgp.createMessage({ text: readableStream }), // input as Message object
        encryptionKeys: publicKey,
        signingKeys: privateKey // optional
    });
    console.log(encrypted); // ReadableStream containing '-----BEGIN PGP MESSAGE ... END PGP MESSAGE-----'

    const message = await openpgp.readMessage({
        armoredMessage: encrypted // parse armored message
    });
    const decrypted = await openpgp.decrypt({
        message,
        verificationKeys: publicKey, // optional
        decryptionKeys: privateKey
    });
    const chunks = [];
    for await (const chunk of decrypted.data) {
        chunks.push(chunk);
    }
    const plaintext = chunks.join('');
    console.log(plaintext); // 'Hello, World!'
})();

Generate new key pair

ECC keys (smaller and faster to generate):

Possible values for curve are: curve25519, ed25519, p256, p384, p521, brainpoolP256r1, brainpoolP384r1, brainpoolP512r1, and secp256k1. Note that both the curve25519 and ed25519 options generate a primary key for signing using Ed25519 and a subkey for encryption using Curve25519.

(async () => {
    const { privateKey, publicKey, revocationCertificate } = await openpgp.generateKey({
        type: 'ecc', // Type of the key, defaults to ECC
        curve: 'curve25519', // ECC curve name, defaults to curve25519
        userIDs: [{ name: 'Jon Smith', email: '[email protected]' }], // you can pass multiple user IDs
        passphrase: 'super long and hard to guess secret', // protects the private key
        format: 'armored' // output key format, defaults to 'armored' (other options: 'binary' or 'object')
    });

    console.log(privateKey);     // '-----BEGIN PGP PRIVATE KEY BLOCK ... '
    console.log(publicKey);      // '-----BEGIN PGP PUBLIC KEY BLOCK ... '
    console.log(revocationCertificate); // '-----BEGIN PGP PUBLIC KEY BLOCK ... '
})();

RSA keys (increased compatibility):

(async () => {
    const { privateKey, publicKey } = await openpgp.generateKey({
        type: 'rsa', // Type of the key
        rsaBits: 4096, // RSA key size (defaults to 4096 bits)
        userIDs: [{ name: 'Jon Smith', email: '[email protected]' }], // you can pass multiple user IDs
        passphrase: 'super long and hard to guess secret' // protects the private key
    });
})();

Revoke a key

Using a revocation certificate:

(async () => {
    const { publicKey: revokedKeyArmored } = await openpgp.revokeKey({
        key: await openpgp.readKey({ armoredKey: publicKeyArmored }),
        revocationCertificate,
        format: 'armored' // output armored keys
    });
    console.log(revokedKeyArmored); // '-----BEGIN PGP PUBLIC KEY BLOCK ... '
})();

Using the private key:

(async () => {
    const { publicKey: revokedKeyArmored } = await openpgp.revokeKey({
        key: await openpgp.readKey({ armoredKey: privateKeyArmored }),
        format: 'armored' // output armored keys
    });
    console.log(revokedKeyArmored); // '-----BEGIN PGP PUBLIC KEY BLOCK ... '
})();

Sign and verify cleartext messages

(async () => {
    const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`;
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with
    const publicKey = await openpgp.readKey({ armoredKey: publicKeyArmored });

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const unsignedMessage = await openpgp.createCleartextMessage({ text: 'Hello, World!' });
    const cleartextMessage = await openpgp.sign({
        message: unsignedMessage, // CleartextMessage or Message object
        signingKeys: privateKey
    });
    console.log(cleartextMessage); // '-----BEGIN PGP SIGNED MESSAGE ... END PGP SIGNATURE-----'

    const signedMessage = await openpgp.readCleartextMessage({
        cleartextMessage // parse armored message
    });
    const verificationResult = await openpgp.verify({
        message: signedMessage,
        verificationKeys: publicKey
    });
    const { verified, keyID } = verificationResult.signatures[0];
    try {
        await verified; // throws on invalid signature
        console.log('Signed by key id ' + keyID.toHex());
    } catch (e) {
        throw new Error('Signature could not be verified: ' + e.message);
    }
})();

Create and verify detached signatures

(async () => {
    const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
...
-----END PGP PUBLIC KEY BLOCK-----`;
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with

    const publicKey = await openpgp.readKey({ armoredKey: publicKeyArmored });

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const message = await openpgp.createMessage({ text: 'Hello, World!' });
    const detachedSignature = await openpgp.sign({
        message, // Message object
        signingKeys: privateKey,
        detached: true
    });
    console.log(detachedSignature);

    const signature = await openpgp.readSignature({
        armoredSignature: detachedSignature // parse detached signature
    });
    const verificationResult = await openpgp.verify({
        message, // Message object
        signature,
        verificationKeys: publicKey
    });
    const { verified, keyID } = verificationResult.signatures[0];
    try {
        await verified; // throws on invalid signature
        console.log('Signed by key id ' + keyID.toHex());
    } catch (e) {
        throw new Error('Signature could not be verified: ' + e.message);
    }
})();

Streaming sign and verify Uint8Array data

(async () => {
    var readableStream = new ReadableStream({
        start(controller) {
            controller.enqueue(new Uint8Array([0x01, 0x02, 0x03]));
            controller.close();
        }
    });
const publicKeyArmored = `-----BEGIN PGP PUBLIC KEY BLOCK-----
END PGP PUBLIC KEY BLOCK-----`;
    const privateKeyArmored = `-----BEGIN PGP PRIVATE KEY BLOCK-----
...
-----END PGP PRIVATE KEY BLOCK-----`; // encrypted private key
    const passphrase = `yourPassphrase`; // what the private key is encrypted with

    const privateKey = await openpgp.decryptKey({
        privateKey: await openpgp.readPrivateKey({ armoredKey: privateKeyArmored }),
        passphrase
    });

    const message = await openpgp.createMessage({ binary: readableStream }); // or createMessage({ text: ReadableStream<String> })
    const signatureArmored = await openpgp.sign({
        message,
        signingKeys: privateKey
    });
    console.log(signatureArmored); // ReadableStream containing '-----BEGIN PGP MESSAGE ... END PGP MESSAGE-----'

    const verificationResult = await openpgp.verify({
        message: await openpgp.readMessage({ armoredMessage: signatureArmored }), // parse armored signature
        verificationKeys: await openpgp.readKey({ armoredKey: publicKeyArmored })
    });

    for await (const chunk of verificationResult.data) {}
    // Note: you *have* to read `verificationResult.data` in some way or other,
    // even if you don't need it, as that is what triggers the
    // verification of the data.

    try {
        await verificationResult.signatures[0].verified; // throws on invalid signature
        console.log('Signed by key id ' + verificationResult.signatures[0].keyID.toHex());
     } catch (e) {
        throw new Error('Signature could not be verified: ' + e.message);
    }
})();

Documentation

The full documentation is available at openpgpjs.org.

Security Audit

To date the OpenPGP.js code base has undergone two complete security audits from Cure53. The first audit's report has been published here.

Security recommendations

It should be noted that js crypto apps deployed via regular web hosting (a.k.a. host-based security) provide users with less security than installable apps with auditable static versions. Installable apps can be deployed as a Firefox or Chrome packaged app. These apps are basically signed zip files and their runtimes typically enforce a strict Content Security Policy (CSP) to protect users against XSS. This blogpost explains the trust model of the web quite well.

It is also recommended to set a strong passphrase that protects the user's private key on disk.

"PRESENTED IN TECHNICOLOR"
💕 Ḻʸⁿˢᴱi ⚡️ 
🐞 Principál Architect 
 ᴸ⧶ Infomtx 🧬 🆁🅳🧪Labs
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment