JOSESwift is a modular and extensible framework for the JOSE standards JWS, JWE, and JWK written in Swift. As of now, its usage is limited to iOS because it relies on the iOS cryptography frameworks.

💡 Please note that this implementation of the JOSE standards is not fully complete yet. For example, there is only a limited set of supported algorithms available at the moment. Moreover we currently only support compact serialization of JOSE types. If you are missing a specific feature, algorithm, or serialization, feel free to submit a pull request.

Contents

• Features
• Installation
  • CocoaPods
  • Carthage
• Usage
  • JWS: Digital Signatures
  • JWE: Encryption and Decryption
  • JWK: Representing Keys
• Security
• Contributing
• Resources
• Contact
• Credits
• License

Features

• JWS: Digitally signing and verifying arbitrary data using the JWS standard.
• JWE: Encrypting and decrypting arbitrary data using the JWE standard.
• JWK: Encoding and decoding cryptographic keys.

If you are missing a specific feature, algorithm, or serialization, feel free to submit a pull request.

Cryptographic Algorithms

🔏 JWS			🔐 JWE					🔑 JWK
Digital Signatures and MACs			Key Management		Content Encryption			Keys
HS256			RSA1_5	✅	A128CBC-HS256	✅		RSA	✅
HS384			RSA-OAEP	✅	A192CBC-HS384			EC	✅
HS512			RSA-OAEP-256	✅	A256CBC-HS512	✅		oct	✅
RS256	✅		A128KW	✅	A128GCM
RS384			A192KW	✅	A192GCM
RS512	✅		A256KW	✅	A256GCM
ES256	✅		dir	✅
ES384	✅		ECDH-ES
ES512	✅		ECDH-ES+A128KW
PS256			ECDH-ES+A192KW
PS384			ECDH-ES+A256KW
PS512			A128GCMKW
			A192GCMKW
			A256GCMKW
			PBES2-HS256+A128KW
			PBES2-HS384+A192KW
			PBES2-HS512+A256KW

Compression Algorithms

JOSESwift supports the DEFLATE compression algorithm for JWE.

DEF
✅

Serializations

For interchangeability JOSESwift currently supports compact serialization for JWS and for JWE.

Compact Serialization	JSON Serialization
✅

Installation

CocoaPods

To integrate JOSESwift into your Xcode project, include it in your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!

target '<Your Target Name>' do
    pod 'JOSESwift'
end

Then install it by running pod install. More documentation on using CocoaPods can be found here.

Carthage

To integrate JOSESwift in your Xcode project, include it in your Cartfile:

github "airsidemobile/JOSESwift"

Then build it by running carthage update and drag the built framework into your Xcode project. More documentation on using Carthage can be found here.

Usage

JOSESwift covers three functional aspects:

1. JWS: Digital Signatures
   • Signing data
   • Verifying data
2. JWE: Encryption and Decryption
   • Encrypting data
   • Decrypting data
3. JWK: Representing Keys
   • Encoding RSA Public Keys
   • Decoding RSA Public Keys

---

JWS: Digital Signatures

A JWS encapsulates and secures data using a digital signature which can be verified by the receiver of the JWS.

Signing Data

In order to construct a JWS we need to provide the following parts:

1. Header
2. Payload
3. Signer

Header

let header = JWSHeader(algorithm: .RS512)

Optionally you can set addtitional parameters:

header.kid = "2018-10-08"

header.typ = "JWS"

Payload

let message = "Summer ⛱, Sun ☀️, Cactus 🌵".data(using: .utf8)!

let payload = Payload(message)

Signer

The signer algorithm must match the header algorithm.

let privateKey: SecKey = /* ... */

let signer = Signer(signingAlgorithm: .RS512, privateKey: privateKey)!

Serializing

The JWS compact serialization is a URL-safe string that can easily be transmitted to a third party using a method of your choice.

guard let jws = try? JWS(header: header, payload: payload, signer: signer) else { ... }

print(jws.compactSerializedString) // ey (...) J9.U3 (...) LU.na (...) 1A

More details about constructing a JWS can be found in the wiki.

Verifying Data

let publicKey: SecKey = /* ... */

let serialization = "ey (..) n0.HK (..) pQ.yS (..) PA.AK (..) Jx.hB (..) 7w"

do {
    let jws = try JWS(compactSerialization: serialization)
    let verifier = Verifier(verifyingAlgorithm: .RS512, publicKey: publicKey)!
    let payload = try jws.validate(using: verifier).payload
    let message = String(data: payload.data(), encoding: .utf8)!

    print(message) // Summer ⛱, Sun ☀️, Cactus 🌵
}

More details about verifying an existing, serialized JWS can be found in the wiki.

---

JWE: Encryption and Decryption

A JWE encapsulates and secures data by encrypting it. It can be decrypted by the receiver of the JWE.

Encrypting Data

In order to construct a JWE we need to provide the following parts:

1. Header
2. Payload
3. Encrypter

Header

let header = JWEHeader(algorithm: .RSA1_5, encryptionAlgorithm: .A256CBCHS512)

Optionally you can set addtitional parameters:

header.kid = "2018-10-08"

header.typ = "JWE"

Payload

let message = "Summer ⛱, Sun ☀️, Cactus 🌵".data(using: .utf8)!

let payload = Payload(message)

Encrypter

The encrypter algorithms must match the header algorithms.

let publicKey: SecKey = /* ... */

let encrypter = Encrypter(keyEncryptionAlgorithm: .RSA1_5, encryptionKey: publicKey, contentEncyptionAlgorithm: .A256CBCHS512)!

Serialization

The JWE compact serialization is a URL-safe string that can easily be transmitted to a third party using a method of your choice.

guard let jwe = try? JWE(header: header, payload: payload, encrypter: encrypter) else { ... }

print(jwe.compactSerializedString) // ey (..) n0.HK (..) pQ.yS (..) PA.AK (..) Jx.hB (..) 7w

More details about constructing a JWE can be found in the wiki.

Decrypting Data

let privateKey: SecKey = /* ... */

let serialization = "ey (..) n0.HK (..) pQ.yS (..) PA.AK (..) Jx.hB (..) 7w"

do {
    let jwe = try JWE(compactSerialization: serialization)
    let decrypter = Decrypter(keyDecryptionAlgorithm: .RSA1_5, decryptionKey: privateKey, contentDecryptionAlgorithm: .A256CBCHS512)!
    let payload = try jwe.decrypt(using: decrypter)
    let message = String(data: payload.data(), encoding: .utf8)!

    print(message) // Summer ⛱, Sun ☀️, Cactus 🌵
}

More details about decrypting an existing, serialized JWE can be found in the wiki.

---

JWK: Representing Keys

A JWK is a JSON data structure that represents a cryptographic key. You could use it, for instance, as the payload of a JWS or a JWE to transmit your public key to a server.

Encoding RSA Public Keys

let publicKey: SecKey = /* ... */

let jwk = try! RSAPublicKey(publicKey: publicKey)

let json = jwk.jsonString()! // {"kty":"RSA","n":"MHZ4L...uS2d3","e":"QVFBQg"}

More details about encoding RSA public keys can be found in the wiki.

Decoding RSA Public Keys

let json: Data = /* ... */

let jwk = try! RSAPublicKey(data: json)

let publicKey: SecKey = try! jwk.converted(to: SecKey.self)

More details about decoding RSA public keys can be found in the wiki.

⚠️ We currently ignore the key parameters "key_ops" and "x5c" when decoding. This is due to a bug in our decoding implementation. See #117 for details.

KW: Encryption and Decryption

let alg = SymmetricKeyAlgorithm.A256KW

let plaintext = "00 11 22 33 44 55 66 77  88 99 aa bb cc dd ee ff".hexadecimalToData()!

let rfcKEK = "00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  10 11 12 13 14 15 16 17  18 19 1a 1b 1c 1d 1e 1f".hexadecimalToData()!

// A[0], the initial value (IV) that enables to verify integrity on the data.
// Equals to: a6 a6 a6 a6 a6 a6 a6 a6 (length: 8 byte)
let iv = Data(bytes: CCrfc3394_iv, count: CCrfc3394_ivLen)

let ciphertext = try! AES.encrypt(plaintext: plaintext, with: rfcKEK, using: alg, and: iv)

let decryptedKey = try! AES.decrypt(cipherText: ciphertext, with: rfcKEK, using: alg, and: iv)

Security

JOSESwift uses the iOS Security framework and Apple’s CommonCrypto for cryptography.

For security disclosures or related matters, please contact joseswift@airsidemobile.com.

See our security policy for more information.

Contributing

Contributions to the project are encouraged and more than welcome. 🤓

If you want to contribute, please submit a pull request. For feature requests, discussions, or bug reports, just open an issue.

See our contributing guidelines for more information.

Resources

You can find detailed information about the relevant JOSE standards in the respective RFCs:

• RFC-7515: JSON Web Signature (JWS)
• RFC-7516: JSON Web Encryption (JWE)
• RFC-7517: JSON Web Key (JWK)
• RFC-7518: JSON Web Algorithms (JWA)

Don’t forget to check our our wiki for more detailed documentation.

Contact

Feel free to contact the project maintainers at joseswift@airsidemobile.com.

Credits

JOSESwift is maintained by Airside Mobile.

Project Authors and Maintainers

@carol-mohemian, @daniel-mohemian, @gigi-mohemian

Reviewers

@haeser, @michael-mohemian

Logo

The logo was designed by Ivan Leuzzi.

Thanks

To the following projects, which served us as reference and inspiration during development:

• Heimdall
• Nimbus JOSE + JWT

License

JOSESwift is licensed under the Apache License 2.0. See LICENSE for details.