Class: Voynich::AES

Inherits:
Object
  • Object
show all
Defined in:
lib/voynich/aes.rb

Constant Summary collapse

AUTH_TAG_BITS = 
128
CIPHER_MODE = 
'aes-256-gcm'
DEFAULT_SERIALIZER = 
Marshal

Instance Method Summary collapse

Constructor Details

#initialize(secret, adata, serializer: DEFAULT_SERIALIZER) ⇒ AES

Returns a new instance of AES.



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# File 'lib/voynich/aes.rb', line 10

def initialize(secret, adata, serializer: DEFAULT_SERIALIZER)
  @secret = secret
  @auth_data = adata
  @serializer = serializer
end

Instance Method Details

#decrypt(content, iv:, tag:) ⇒ Object 



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# File 'lib/voynich/aes.rb', line 32

def decrypt(content, iv:, tag:)
  cipher = OpenSSL::Cipher.new(CIPHER_MODE)
  cipher.decrypt
  cipher.key = @secret
  cipher.iv = Base64.decode64(iv)
  cipher.auth_tag = Base64.decode64(tag)
  cipher.auth_data = @auth_data
  decrypted_data = cipher.update(Base64.decode64(content)) + cipher.final
  deserialize(decrypted_data)
end

#deserialize(data) ⇒ Object 



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# File 'lib/voynich/aes.rb', line 47

def deserialize(data)
  @serializer.load(data)
end

#encrypt(plaintext) ⇒ Object 



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# File 'lib/voynich/aes.rb', line 16

def encrypt(plaintext)
  cipher = OpenSSL::Cipher.new(CIPHER_MODE)
  cipher.encrypt
  cipher.key = @secret
  iv = cipher.random_iv
  cipher.auth_data = @auth_data
  encrypted_data = cipher.update(serialize(plaintext)) + cipher.final
  tag = cipher.auth_tag(AUTH_TAG_BITS / 8)
  {
    content: Base64.strict_encode64(encrypted_data),
    tag:     Base64.strict_encode64(tag),
    iv:      Base64.strict_encode64(iv),
    auth_data: @auth_data
  }
end

#serialize(data) ⇒ Object 



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# File 'lib/voynich/aes.rb', line 43

def serialize(data)
  @serializer.dump(data)
end