Crypto Crystal

Pure Crystal port of pyrogram/tgcrpto. Implements various Cryptograpgy algorithms that are especially usefull for Telegram's MTPtoto protocol.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     crypto:
       github: watzon/crypto

2. Run shards install

API

module Crypto
  module AES
    def self.create_encryption_key(key : Bytes) : Slice(UInt32)
    def self.create_decryption_key(key : Bytes) : Slice(UInt32)
    def self.encrypt(data : Bytes, key : Indexable(UInt32)) : Bytes
    def self.decrypt(data : Bytes, key : Indexable(UInt32)) : Bytes
  end

  module CBC
    def self.encrypt(data : Bytes, key : Bytes, iv : Bytes) : Bytes
    def self.decrypt(data : Bytes, key : Bytes, iv : Bytes) : Bytes
  end

  module CTR
    def self.xcrypt(data : Bytes, key : Bytes, iv : Bytes, state : Bytes = [0_u8]) : Bytes
  end

  module IGE
    def self.encrypt(data : Bytes, key : Bytes, iv : Bytes) : Bytes
    def self.decrypt(data : Bytes, key : Bytes, iv : Bytes) : Bytes
  end

  module Padding
    def self.pkcs7(buffer : Bytes, block_size : Int)
  end
end

Usage

IGE Mode

Note: Data must be padded to match a multiple of the block size AES::BLOCK_SIZE.

require "crypto"

random = Random.new

# 10 MB of random data + 7 bytes to show padding
data = random.random_bytes(10 * 1024 * 1024 + 7)

key = random.random_bytes(32) # Random key
iv = random.random_bytes(32) # Random iv

# Pad the data using PKCS7
data = Crypto::Padding.pkcs7(data, Crypto::AES::BLOCK_SIZE)

encrypted = Crypto::IGE.encrypt(data, key, iv)
decrypted = Crypto::IGE.decrypt(encrypted, key, iv)

puts data == decrypted
# => true

CTR Mode

require "crypto"

random = Random.new

# 10 MB of random data + 7 bytes to show padding
data = random.random_bytes(10 * 1024 * 1024 + 7)

key = random.random_bytes(32) # Random key
iv = random.random_bytes(16) # Random iv

# Pad the data using PKCS7
data = Crypto::Padding.pkcs7(data, Crypto::AES::BLOCK_SIZE)

encrypted = Crypto::CTR.xcrypt(data, key, iv)
decrypted = Crypto::CTR.xcrypt(encrypted, key, iv)

puts data == decrypted

CBC Mode

Note: Data must be padded to match a multiple of the block size AES::BLOCK_SIZE.

require "crypto"

random = Random.new

# 10 MB of random data + 7 bytes to show padding
data = random.random_bytes(10 * 1024 * 1024 + 7)

key = random.random_bytes(32) # Random key
iv = random.random_bytes(16) # Random iv

# Pad the data using PKCS7
data = Crypto::Padding.pkcs7(data, Crypto::AES::BLOCK_SIZE)

encrypted = Crypto::CBC.encrypt(data, key, iv)
decrypted = Crypto::CBC.decrypt(encrypted, key, iv)

puts data == decrypted

Roadmap

• [ ] Cipher Based
  • [ ] AES
    • [ ] 128
    • [ ] 192
    • [x] 256
  • [ ] CBC
    • [ ] 128
    • [ ] 192
    • [x] 256
  • [ ] CTR
    • [ ] 128
    • [ ] 192
    • [x] 256
  • [ ] IGE
    • [ ] 128
    • [ ] 192
    • [x] 256
• [x] Public Key Cryptography
  • [x] RSA
• Hashing
  • [ ] Blake
    • [x] Blake2b
    • [ ] Blake2s
    • [ ] Blake3
    • [ ] Argon2
• [ ] Key Derivation Functions
  • [ ] KDF
    • [ ] PBKDF2
• [ ] More?

Contributing

1. Fork it (https://github.com/watzon/crypto/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Chris Watson - creator and maintainer