Class: Noise::Functions::Cipher::ChaChaPoly

Inherits:
Object
  • Object
show all
Defined in:
lib/noise/functions/cipher/cha_cha_poly.rb

Constant Summary collapse

MAX_NONCE = 
2**64 - 1

Instance Method Summary collapse

Instance Method Details

#decrypt(k, n, ad, ciphertext) ⇒ Object 



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# File 'lib/noise/functions/cipher/cha_cha_poly.rb', line 16

def decrypt(k, n, ad, ciphertext)
  cipher = RbNaCl::AEAD::ChaCha20Poly1305IETF.new(String.new(k).force_encoding('ASCII-8BIT'))
  cipher.decrypt(nonce_to_bytes(n), ciphertext, ad)
rescue ::RbNaCl::CryptoError => e
  raise Noise::Exceptions::DecryptError, "Decrpyt failed. #{e.message}", e.backtrace
end

#encrypt(k, n, ad, plaintext) ⇒ Object 



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# File 'lib/noise/functions/cipher/cha_cha_poly.rb', line 9

def encrypt(k, n, ad, plaintext)
  cipher = RbNaCl::AEAD::ChaCha20Poly1305IETF.new(String.new(k).force_encoding('ASCII-8BIT'))
  cipher.encrypt(nonce_to_bytes(n), plaintext, ad)
rescue ::RbNaCl::CryptoError => e
  raise Noise::Exceptions::EncryptError, "Encrypt failed. #{e.message}", e.backtrace
end

#nonce_to_bytes(n) ⇒ Object

4 zero bytes followed by n as a little-endian 64 bit integer.



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# File 'lib/noise/functions/cipher/cha_cha_poly.rb', line 24

def nonce_to_bytes(n)
  "\x00" * 4 + [n].pack('Q<')
end

#rekey(k) ⇒ Object

Returns a new 32-byte cipher key as a pseudorandom function of k. If this function is not specifically defined for some set of cipher functions, then it defaults to returning the first 32 bytes from ENCRYPT(k,maxnonce, zerolen, zeros), where maxnonce equals 2**64-1, zerolen is a zero-length byte sequence, and zeros is a sequence of 32 bytes filled with zeros.



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# File 'lib/noise/functions/cipher/cha_cha_poly.rb', line 34

def rekey(k)
  encrypt(k, MAX_NONCE, '', "\x00" * 32)[0...32]
end