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Pointy Castle - Dart Derived Bouncy Castle APIs
https://github.com/bcgit/pc-dart

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Pointy Castle - Dart Derived Bouncy Castle APIs

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README 

        

Pointy Castle

=============



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A Dart library for encryption and decryption. In this release, most of the classes are ports of Bouncy Castle from Java

to Dart. The porting is almost always direct except for some classes that had been added to ease the use of low level

data.



To make sure nothing fails, tests and benchmarks for every algorithm are

provided. The expected results are taken from the Bouncy Castle Java version

and also from standards, and matched against the results got from Pointy Castle.



This library was adopted from the original project at https://github.com/PointyCastle/pointycastle at the request of the

 authors to help support ongoing development. A list of major contributors is provided at contributors.md



This library is now ported to non-nullable-by-default, a breaking language feature released by the Dart team! See

https://dart.dev/null-safety and https://dart.dev/null-safety/migration-guide for more details. Please note that both

null-safe and non-null-safe versions are available (v3.x.x-nullsafety for null-safe, v2.x.x for non-null-safe). However,

only the null-safe version of this library is actively maintained. 



## Algorithms



Pointycastle implements a large set of algorithms. They must be instantiated and then initialized with

their parameters. Different algorithms have different parameter classes, which represent the

arguments to that algorithm. The relevant parameter type is provided for all the algorithms. To initialize an algorithm, 

call the init method:

```dart

var algorithmVar = /* instantiate algorithm using registry here */ ;

var parameter = /* instantiate relevant parameter class here */ ;

algorithmVar.init(parameter);

```

Some algorithms will ask for more than just a parameter object in the initialization step. Once you have identified the

classes you intend to use in your project, it is recommended that you view the API docs at 

https://pub.dev/documentation/pointycastle/latest/ to find the specifics of the methods from the 

class you want to use.



In this release, the following algorithms are implemented:



(Most of the below are keywords for algorithms which can be used directly with the registry. The registry is an easy way

to instantiate classes in PointyCastle. See "Using the Registry" for more).



**AEAD ciphers:** To use with the registry, instantiate like this `AEADCipher('ChaCha20-Poly1305')`. Ciphers use `AEADParameters` to initialize.



* 'ChaCha20-Poly1305'

* 'AES/EAX'



**Block ciphers:** To use with the registry, instantiate like this `PaddedBlockCipher('AES/SomeBlockModeHere/SomePaddingHere')` 

or like this `StreamCipher('AES/SomeStreamModeHere')`. See sections below for modes and paddings.

  * 'AES'

  * *Note that block ciphers can be used in stream cipher modes of operation*

  

**Block modes of operation:** Most modes use `ParametersWithIV` to initialize. ECB uses `KeyParameter` and GCM uses `AEADParameters`.

  * 'CBC' (Cipher Block Chaining mode)

  * 'ECB' (Electronic Code Book mode)

  * 'CFB-64' (Cipher Feedback mode, using blocks)

  * 'GCTR' (GOST 28147 OFB counter mode, using blocks)

  * 'OFB-64' (Output FeedBack mode, using blocks)

  * 'CTR'/'SIC' (Counter mode, using blocks)

  * 'IGE' (Infinite Garble Extension)

  * **Authenticated block modes of operation**

     - 'GCM' (Galois-Counter mode)

     - 'CCM' (counter with CBC-MAC)

     

**Stream modes of operation:** All modes use `ParametersWithIV` to initialize.

  * 'CTR'/'SIC' (Counter mode, as a traditional stream)



**Paddings:**

  * 'PKCS7'

  * 'ISO7816-4'



**Asymmetric block ciphers:** Instantiate using the registry like this `AsymmetricBlockCipher('RSA/SomeEncodingHere')`. Initialization requires a `RSAPrivateKey` or `RSAPublicKey`.

  * 'RSA'



**Asymmetric block cipher encodings:**

  * 'PKCS1'

  * 'OAEP'



**Stream ciphers:** Instantiation using registry is like this `StreamCipher('ChaCha20/20')`. Initialization requires a `ParametersWithIV`.

  * 'Salsa20'

  * 'ChaCha20/(# of rounds)' (original implementation)

  * 'ChaCha7539/(# of rounds)' (RFC-7539 implementation)

  * If you don't know how many ChaCha rounds to use, use 20.



**Digests:** Instantiate using registry like this `Digest('Keccak/384')`. No initialization is necessary.

  * 'Blake2b'

  * 'MD2'

  * 'MD4'

  * 'MD5'

  * 'RIPEMD-128|160|256|320'

  * 'SHA-1'

  * 'SHA-224|256|384|512'

  * 'SHA-512/t' (t=8 to 376 and 392 to 504 in multiples of 8)

  * 'Keccak/224|256|384|512'

  * 'SHA3-224|256|384|512'

  * 'Tiger'

  * 'Whirlpool'

  * 'SM3'



**MACs:** Instantiate using registry like this `Mac('SomeBlockCipher/CMAC')` or `Mac('SomeDigest/HMAC)` or `Mac(SomeBlockCipher/Poly1305)`. CMAC and HMAC require a `KeyParameter` and Poly1305 requires a `ParametersWithIV`.

  * 'HMAC'

  * 'CMAC'

  * 'Poly1305'



**Signatures:** Instantiate using registry like this `Signer('SomeDigestHere/(DET-)ECDSA')` or `Signer('SomeDigestHere/RSA')`

  * '(DET-)ECDSA'

  * 'RSA'



**Password based key derivators:** Instantiation using registry like this `KeyDerivator('SomeDigestHere/HMAC/PBKDF2')` 

or `KeyDerivator('scrypt/argon2')`. To initialize, you'll need a `Pbkdf2Parameters`, `ScryptParameters`, or 

`Argon2Parameters`.

  * 'PBKDF2'

  * 'scrypt'

  * 'argon2'



**HMAC based key derivators:** Instantiate using registry like this `KeyDerivator('SomeDigestHere/HKDF')`. To initialize, use an `HkdfParameters`.

  * 'HKDF'



**Asymmetric key generators** Instantiate using registry like this `KeyDerivator('RSA')`. To initialize, use `ECKeyGeneratorParameters` or `RSAKeyGeneratorParameters`.

  * 'ECDSA'

  * 'RSA'



**Secure PRNGs:**

  * Based on block cipher in CTR mode

  * Based on block cipher in CTR mode with auto reseed (for forward security)

  * Based on Fortuna algorithm



### Instantiating implementation objects



There are two ways to instantiate objects that implement the

algorithms:



- using the registry, or

- without the registry.



#### Using the registry



Using the registry, the algorithm name is provided to high-level class

factories.



This is especially convenient when an algorithm involves multiple

algorithm implementation classes to implement. All the necessary

classes can all be instantiated with a single name

(e.g. "SHA-256/HMAC" or "SHA-1/HMAC/PBKDF2" or "AES/CBC/PKCS7"), and they are

automatically combined together with the correct values.



For example,



```dart

final sha256 = Digest("SHA-256");

final sha1 = Digest("SHA-1");

final md5 = Digest("MD5");



final hmacSha256 = Mac("SHA-256/HMAC");

final hmacSha1 = Mac("SHA-1/HMAC");

final hmacMd5 = Mac("MD5/HMAC");



final derivator = KeyDerivator("SHA-1/HMAC/PBKDF2");



final signer = Signer("SHA-256/RSA");

```



#### Without the registry



Without the registry, each implementation class must be instantiated

using its constructor.



If an algorithm involves multiple algorithm implementation classes,

they each have to be individually instantiated and combined together

with the correct values.



For example,



``` dart

final sha256 = SHA256Digest();

final sha1 = SHA1Digest();

final md5 = MD5Digest();



final hmacSha256 = HMac(SHA256Digest(), 64);

final hmacSha512 = HMac(SHA512Digest(), 128);

final hmacMd5 = HMac(MD5Digest(), 64);



final derivator = PBKDF2KeyDerivator(HMac(SHA256Digest(), 64));



final signer = RSASigner(SHA256Digest(), '0609608648016503040201');

```



#### Registry vs without registry



Using the registry means that all algorithms will be imported by

default, which can increase the compiled size of your program.



To avoid this, instantiate all classes directly by using the

constructors. But which classes can be instantiated with its

constructor will depend on which libraries have been imported.



### Importing libraries



A program can take one of these three approaches for importing Point

Castle libraries:



- only import pointycastle.dart;

- only import exports.dart; or

- import api.dart and individual libraries as needed.



#### Only import pointycastle.dart



The "pointycastle.dart" file exports:



- the high-level API; and

- implementations of the interfaces.



But it does not export any of the algorithm implementation classes.



``` dart

import "package:pointycastle/pointycastle.dart";

```



With this import, **none** of the implementation classes can be

instantiated directly.  The program can only use the registry.



For example,



``` dart

final sha256 = Digest("SHA-256");

// final md5 = MD5Digest(); // not available

final p = Padding("PKCS7");

// final s = FortunaRandom(); // not available

```



#### Only import exports.dart



The "export.dart" file exports:



- the high-level API,

- implementations of the interfaces; and

- every algorithm implementation class.



That is, everything!



``` dart

import "package:pointycastle/export.dart";

```



With this import, **all** of the implementation classes can be

instantiated directly.  The program can also use the registry.



For example, this works without any additional imports:



``` dart

final sha256 = Digest("SHA-256");

final md5 = MD5Digest();

final p = Padding("PKCS7");

final s = FortunaRandom();

```



#### Import api.dart and individual libraries



The "api.dart" exports only:



- the high-level API.



It does not include the implementations of the interfaces, nor any

algorithm implementation class.



``` dart

import "package:pointycastle/api.dart";

// additional imports will be needed

```



With this import, only **some** of the implementation classes can be

instantiated directly (i.e. those that are also explicitly imported).

The program can also use the registry.



For example, the following only works because of the additional imports:



``` dart

// In addition to "package:pointycastle/api.dart":

import "package:pointycastle/digests/sha256.dart";

import "package:pointycastle/digests/md5.dart"

import 'package:pointycastle/paddings/pkcs7.dart';



final sha256 = Digest("SHA-256");

final md5 = MD5Digest();

final p = Padding("PKCS7");

// final s = FortunaRandom(); // not available without 'package:pointycastle/random/fortuna_random.dart'

```



## Tutorials



Some articles on how to use some of Pointy Castle's features can be

found under the _tutorials_ directory in the sources.



- [Calculating a digest](https://github.com/bcgit/pc-dart/blob/master/tutorials/digest.md) - calculating a hash or digest (e.g. SHA-256, SHA-1, MD5)

- [Calculating a HMAC](https://github.com/bcgit/pc-dart/blob/master/tutorials/hmac.md) - calculating a hash-based message authentication code (e.g. HMAC-SHA256, HMAC-SHA1)

- [Using AES-CBC](https://github.com/bcgit/pc-dart/blob/master/tutorials/aes-cbc.md) - block encryption and decryption with AES-CBC

- [Using RSA](https://github.com/bcgit/pc-dart/blob/master/tutorials/rsa.md) - key generation, signing/verifying, and encryption/decryption

- Some [tips](https://github.com/bcgit/pc-dart/blob/master/tutorials/tips.md) on using Pointy Castle



_Note: the above links are to the most recent versions on the master branch on GitHub. They may be different from the version on pub.dev._