Class: BlockCipherKit::BaseScheme

Inherits:
Object
  • Object
show all
Defined in:
lib/block_cipher_kit/base_scheme.rb

Instance Method Summary collapse

Instance Method Details

#decrypt_range(from_ciphertext_io:, range:) ⇒ String

Decrypts the desired range of the ciphered message, reading ciphertext out of from_ciphertext_io. Reading requires the from_ciphertext_io to be seekable - it must support #pos, #readand #seek. The decrypted plaintext gets returned as a single concatenated String.

Parameters:

  • from_ciphertext_io (RandomReadIO) —

    Ciphertext will be read from that IO. The IO must support random access.

  • range (Range) —

    range of bytes in plaintext offsets to decrypt. Endless ranges are supported.

Returns:

  • (String) —

    the decrypted bytes located at the given offset range inside the plaintext



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# File 'lib/block_cipher_kit/base_scheme.rb', line 61

def decrypt_range(from_ciphertext_io:, range:)
  buf = StringIO.new.binmode
  streaming_decrypt_range(from_ciphertext_io: from_ciphertext_io, range: range, into_plaintext_io: buf)
  buf.string
end

#inspect ⇒ Object 



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# File 'lib/block_cipher_kit/base_scheme.rb', line 67

def inspect
  # A reimplementation of #inspect based largely on
  # https://alchemists.io/articles/ruby_object_inspection
  pattern = +""
  values = []

  instance_variables.each do |name|
    pattern << "#{name}=%s "
    ivar_value = instance_variable_get(name)
    if ivar_value.is_a?(String) && key_material_instance_variable_names.include?(name)
      values.push("[SENSITIVE(#{ivar_value.bytesize * 8} bits)]")
    else
      values.push(ivar_value.inspect)
    end
  end

  format "#<%s:%#018x #{pattern.strip}>", self.class, object_id << 1, *values
end

#streaming_decrypt(from_ciphertext_io:, into_plaintext_io: nil) {|String| ... } ⇒ void

This method returns an undefined value.

Decrypts the entire ciphered message, reading ciphertext out of from_ciphertext_io until its read returns nil (until EOF is implicitly reached). The scheme will also read any data at the start of the IO that it requires for operation, and consume the IO until exhaustion.

Parameters:

  • from_ciphertext_io (StraightReadableIO) —

    An IO-ish that responds to read with one argument, ciphertext will be read from that IO

  • into_plaintext_io (WritableIO) (defaults to: nil) —

    An IO-ish that responds to write with one argument. If into_plaintext_io is not provided, the block passed to the method will receive String objects in binary encoding with chunks of decrypted ciphertext. The sizing of the chunks is defined by the cipher and the read size used by IO.copy_stream

Yields:

  • (String) —

    the chunk of decrypted bytes



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# File 'lib/block_cipher_kit/base_scheme.rb', line 15

def streaming_decrypt(from_ciphertext_io:, into_plaintext_io: nil, &blk)
  raise "Unimplemented"
end

#streaming_decrypt_range(from_ciphertext_io:, range:, into_plaintext_io: nil) {|String| ... } ⇒ void

This method returns an undefined value.

Decrypts the desired range of the ciphered message, reading ciphertext out of from_ciphertext_io. Reading requires the from_ciphertext_io to be seekable - it must support #pos, #readand #seek. The decrypted plaintext either gets written into into_plaintext_io if it is provided, or yielded to the passed block in String chunks.

Parameters:

  • from_ciphertext_io (RandomReadIO) —

    Ciphertext will be read from that IO. The IO must support random access.

  • range (Range) —

    range of bytes in plaintext offsets to decrypt. Endless ranges are supported.

  • into_plaintext_io (WritableIO) (defaults to: nil) —

    An IO-ish that responds to write with one argument. If into_plaintext_io is not provided, the block passed to the method will receive String objects in binary encoding with chunks of decrypted ciphertext. The sizing of the chunks is defined by the cipher and the read size used by IO.copy_stream

Yields:

  • (String) —

    the chunk of decrypted bytes



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# File 'lib/block_cipher_kit/base_scheme.rb', line 50

def streaming_decrypt_range(from_ciphertext_io:, range:, into_plaintext_io: nil, &blk)
  raise "Unimplemented"
end

#streaming_encrypt(into_ciphertext_io:, from_plaintext_io: nil) {|#write| ... } ⇒ void

This method returns an undefined value.

Encrypts the entire ciphered message, reading plaintext either from the from_plaintext_io until its read returns nil (until EOF is implicitly reached) or from writes to the object it yields (for streaming writes).

The scheme will also write any leading data at the start of the output that should prefix the ciphertext (usually the IV) and any trailing data after the ciphertext (like a validation tag for cipher authentication) into the into_ciphertext_io.

Parameters:

  • from_plaintext_io (StraightReadableIO, nil) (defaults to: nil) —

    An IO-ish that responds to read with one argument. If from_plaintext_io is not provided, the block passed to the method will receive an IO-ish object that responds to #write that plaintext can be written into.

  • into_ciphertext_io (WritableIO) —

    An IO-ish that responds to write with one argument,

Yields:

  • (#write) —

    IO-ish writable that accepts strings of plaintext into #write



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# File 'lib/block_cipher_kit/base_scheme.rb', line 33

def streaming_encrypt(into_ciphertext_io:, from_plaintext_io: nil, &blk)
  raise "Unimplemented"
end