kitura/bluersa

Swift cross-platform RSA wrapper library for RSA encryption and signing. Works on supported Apple platforms (using Security framework). Linux (using OpenSSL) is working but is still somewhat of a work in progress.

CryptorRSA: Utility functions for RSA encryption and signing. Pure Swift

Prerequisites

Swift

Swift Open Source swift-4.0.0-RELEASE toolchain (Minimum REQUIRED for latest release)
Swift Open Source swift-5.2-RELEASE toolchain (Recommended)
Swift toolchain included in Xcode Version 10.0 (10A255) or higher.

macOS

macOS 11.5.0 (Big Sur) or higher
Xcode Version 12.0 (9A325) or higher using the included toolchain (Minimum REQUIRED for latest release).
Xcode Version 13.4.1 (13F100) or higher using the included toolchain (Recommended).

iOS

iOS 14.5 or higher
Xcode Version 9.0 (9A325) or higher using the included toolchain (Minimum REQUIRED for latest release).
Xcode Version 13.4.1 (13F100) or higher using the included toolchain (Recommended).

Linux

Ubuntu 16.04 (or 16.10 but only tested on 16.04) and 18.04.
One of the Swift Open Source toolchain listed above.
OpenSSL is provided by the distribution. Note: 1.0.x, 1.1.x and later releases of OpenSSL are supported.
The appropriate libssl-dev package is required to be installed when building.

Build

To build CryptorRSA from the command line:

% cd <path-to-clone>
% swift build

Testing

To run the supplied unit tests for CryptorRSA from the command line:

% cd <path-to-clone>
% swift build
% swift test

Using CryptorRSA

### Including in your project

#### Swift Package Manager

To include BlueRSA into a Swift Package Manager package, add it to the `dependencies` attribute defined in your `Package.swift` file. You can select the version using the `majorVersion` and `minor` parameters. For example:
```
	dependencies: [
		.package(url: "https://github.com/Kitura/BlueRSA", majorVersion: <majorVersion>, minor: <minor>)
	]
```

#### Carthage

To include BlueRSA in a project using Carthage, add a line to your `Cartfile` with the GitHub organization and project names and version. For example:
```
	github "Kitura/BlueRSA" ~> <majorVersion>.<minor>
```

### Before starting

The first you need to do is import the CryptorRSA framework.  This is done by the following:

```
import CryptorRSA
```

### Data Types

BlueRSA supports the following *major* data types:

* Key Handling
	- `CryptorRSA.PublicKey` - Represents an RSA Public Key.
	- `CryptorRSA.PrivateKey` - Represents an RSA Private Key.

* Data Handling
	- `CryptorRSA.EncryptedData` - Represents encrypted data.
	- `CryptorRSA.PlaintextData` - Represents plaintext or decrypted data.
	- `CryptorRSA.SignedData` - Represents signed data.

### Key Handling

**BlueRSA** provides seven (7) functions each for creating public and private keys from data. They are as follows (where *createXXXX* is either `createPublicKey` or `createPrivateKey` depending on what you're trying to create):

- `CryptorRSA.createXXXX(with data: Data) throws` - This creates either a private or public key containing the data provided. *It is assumed that the data being provided is in the proper format.*
- `CryptorRSA.createXXXX(withBase64 base64String: String) throws` - This creates either a private or public key using the `Base64 encoded String` provided.
- `CryptorRSA.createXXXX(withPEM pemString: String) throws` - This creates either a private or public key using the `PEM encoded String` provided.
- `CryptorRSA.createXXXX(withPEMNamed pemName: String, onPath path: String) throws` - This creates either a private or public key using the `PEM encoded file` pointed at by the `pemName` and located on the path specified by `path` provided.
- `CryptorRSA.createXXXX(withDERNamed derName: String, onPath path: String) throws` - This creates either a private or public key using the `DER encoded file` pointed at by the `derName` and located on the path specified by `path` provided.
- `CryptorRSA.createXXXX(withPEMNamed pemName: String, in bundle: Bundle = Bundle.main) throws` - This creates either a private or public key using the `PEM encoded file` pointed at by the `pemName` and located in the `Bundle` specified by `bundle` provided. By default this API will look in the `main` bundle. **Note: Apple Platforms Only**
- `CryptorRSA.createXXXX(withDERNamed derName: String, in bundle: Bundle = Bundle.main) throws` - This creates either a private or public key using the `DER encoded file` pointed at by the `derName` and located in the `Bundle` specified by `bundle` provided. By default this API will look in the `main` bundle. **Note: Apple Platforms Only**

Additionally, there are three APIs for creating a *public key* by extracting the key from a PEM formatted certificate:  They are:

- `CryptorRSA.createPublicKey(extractingFrom data: Data) throws` - This creates either a public key by extracting from the `PEM encoded certificate` pointed at by the `data`.
- `CryptorRSA.createPublicKey(extractingFrom certName: String, onPath path: String) throws` - This creates a public key by extracting from the `PEM encoded certificate` pointed at by the `certName` and located on the path specified by `path` provided.
- `CryptorRSA.createPublicKey(extractingFrom certName: String, in bundle: Bundle = Bundle.main) throws` - This creates a public key using the `PEM encoded certificate` pointed at by the `derName` and located in the `Bundle` specified by `bundle` provided. By default this API will look in the `main` bundle. **Note: Apple Platforms Only**


**Example**

The following example illustrates creating a public key given PEM encoded file located on a certain path. *Note: Exception handling omitted for brevity.

```
import Foundation
import CryptorRSA

...

let keyName = ...
let keyPath = ...

let publicKey = try CryptorRSA.createPublicKey(withPEMNamed: keyName, onPath: keyPath)

...

<Do something with the key...>

```

### Data Encryption and Decryption Handling

**BlueRSA** provides functions for the creation of each of the three (3) data handling types:

**Plaintext Data Handling and Signing**

There are two class level functions for creating a `PlaintextData` object. These are:

- `CryptorRSA.createPlaintext(with data: Data) -> PlaintextData` - This function creates a `PlaintextData` containing the specified `data`.
- `CryptorRSA.createPlaintext(with string: String, using encoding: String.Encoding) throws -> PlaintextData` - This function creates a `PlaintextData` object using the `string` encoded with the specified `encoding` as the data.

Once the `PlaintextData` object is created, there are two instance functions that can be used to manipulate the contained data.  These are:

- `encrypted(with key: PublicKey, algorithm: Data.Algorithm) throws -> EncryptedData?` - This function allows you to encrypt containing data using the public `key` and `algorithm` specified.  This function returns an optional `EncryptedData` object containing the encryped data.
- `signed(with key: PrivateKey, algorithm: Data.Algorithm) throws -> SignedData?` - This function allows you to sign the contained data using the private `key` and `algorithm` specified.  This function returns an optional `SignedData` object containing the signature of the signed data.

**Example**

- *Encryption*: **Note:** Exception handling omitted for brevity.

```
import Foundation
import CryptorRSA

...

let keyName = ...
let keyPath = ...

let myData: Data = <... Data to be encrypted ...>

let publicKey = try CryptorRSA.createPublicKey(withPEMNamed: keyName, onPath: keyPath)
let myPlaintext = CryptorRSA.createPlaintext(with: myData)
let encryptedData = try myPlaintext.encrypted(with: publicKey, algorithm: .sha1)

...

< Do something with the encrypted data...>

```

- *Signing*: **Note:** Exception handling omitted for brevity.

```
import Foundation
import CryptorRSA

...

let keyName = ...
let keyPath = ...

let myData: Data = <... Data to be signed ...>

let privateKey = try CryptorRSA.createPrivateKey(withPEMNamed: keyName, onPath: keyPath)
let myPlaintext = CryptorRSA.createPlaintext(with: myData)
let signedData = try myPlaintext.signed(with: privateKey, algorithm: .sha1)

...

< Do something with the signed data...>

```
**Encrypted Data Handling**

There are two class level functions for creating a `EncryptedData` object. These are:

- `CryptorRSA.createEncrypted(with data: Data) -> EncryptedData` - This function creates a `EncryptedData` containing the specified encrypted `data`.
- `CryptorRSA.createEncrypted(with base64String: String) throws -> EncryptedData` - This function creates a `EncrpytedData` using the *Base64* representation of already encrypted data.

Once the `EncryptedData` object is created, there is an instance function that can be used to decrypt the enclosed data:

- `decrypted(with key: PrivateKey, algorithm: Data.Algorithm) throws -> DecryptedData?` - This function allows you to decrypt containing data using the public `key` and `algorithm` specified.  This function returns an optional `DecryptedData` object containing the encryped data.

BlueRSA currently supports `OAEP` padding, which is the recommended padding algorithm. 

**Example**

- *Decryption*: **Note**: Exception handling omitted for brevity.

```
import Foundation
import CryptorRSA

...

let keyName = ...
let keyPath = ...
let publicKey = try CryptorRSA.createPublicKey(withPEMNamed: keyName, onPath: keyPath)

let pkeyName = ...
let pkeyPath = ...
let privateKey = try CryptorRSA.createPrivateKey(withPEMNamed: pkeyName, onPath: pkeyPath)

let myData: Data = <... Data to be encrypted ...>

let myPlaintext = CryptorRSA.createPlaintext(with: myData)
let encryptedData = try myPlaintext.encrypted(with: publicKey, algorithm: .sha1)

let decryptedData = try encryptedData.decrypted(with: privateKey, algorithm: .sha1)

...

< Do something with the decrypted data...>


```


### Signature Verification Handling

There is a single class level function that can be used to create a `SignedData` object. It is:

- `CryptorRSA.createSigned(with data: Data) -> SignedData` - This function creates a `SignedData` containing the specified signed `data`.

Once created or obtained `PlaintextData` and `SignedData`, there is an instance function which can be used to verify the signature contained therein:

- `verify(with key: PublicKey, signature: SignedData, algorithm: Data.Algorithm) throws -> Bool` - This function is used to verify, using the public `key` and `algorithm`, the `signature`.  Returns true if the signature is valid, false otherwise.

- *Verifying*: **Note:** Exception handling omitted for brevity.

```
import Foundation
import CryptorRSA

...

let keyName = ...
let keyPath = ...
let publicKey = try CryptorRSA.createPublicKey(withPEMNamed: keyName, onPath: keyPath)

let pkeyName = ...
let pkeyPath = ...
let privateKey = try CryptorRSA.createPrivateKey(withPEMNamed: pkeyName, onPath: pkeyPath)

let myData: Data = <... Data to be signed ...>

let myPlaintext = CryptorRSA.createPlaintext(with: myData)
let signedData = try myPlaintext.signed(with: privateKey, algorithm: .sha1)

if try myPlaintext.verify(with: publicKey, signature: signedData, algorithm: .sha1) {

	print("Signature verified")

} else {

	print("Signature Verification Failed")
}

```

### Data Type Utility Functions

All three of the data handling types have two common utility instance functions.  These are:

- `digest(using algorithm: Data.Algorithm) throws -> Data` - This function returns a `Data` object containing a digest constructed using the specified `algorithm`.
- `string(using encoding: String.Encoding) throws -> String` - This functions returns a `String` representation of the data using the specified `encoding`.

Community

We love to talk server-side Swift and Kitura. Join our Slack to meet the team!

License

This library is licensed under Apache 2.0. Full license text is available in LICENSE.

Package Metadata

Repository: kitura/bluersa

Default branch: master

README: README.md