Class: JOSE::JWE::ENC_AES_GCM

Inherits:
Struct
  • Object
show all
Defined in:
lib/jose/jwe/enc_aes_gcm.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#bits ⇒ Object

Returns the value of attribute bits

Returns:

  • (Object) —

    the current value of bits



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 1

def bits
  @bits
end

#cek_len ⇒ Object

Returns the value of attribute cek_len

Returns:

  • (Object) —

    the current value of cek_len



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 1

def cek_len
  @cek_len
end

#cipher_name ⇒ Object

Returns the value of attribute cipher_name

Returns:

  • (Object) —

    the current value of cipher_name



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 1

def cipher_name
  @cipher_name
end

#iv_len ⇒ Object

Returns the value of attribute iv_len

Returns:

  • (Object) —

    the current value of iv_len



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 1

def iv_len
  @iv_len
end

Class Method Details

.from_map(fields) ⇒ Object

JOSE::JWE callbacks



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 5

def self.from_map(fields)
  case fields['enc']
  when 'A128GCM'
    return new('aes-128-gcm', 128, 16, 12), fields.delete('enc')
  when 'A192GCM'
    return new('aes-192-gcm', 192, 24, 12), fields.delete('enc')
  when 'A256GCM'
    return new('aes-256-gcm', 256, 32, 12), fields.delete('enc')
  else
    raise ArgumentError, "invalid 'enc' for JWE: #{fields['enc'].inspect}"
  end
end

Instance Method Details

#algorithm ⇒ Object

JOSE::JWE::ENC callbacks



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 24

def algorithm
  case cipher_name
  when 'aes-128-gcm'
    return 'A128GCM'
  when 'aes-192-gcm'
    return 'A192GCM'
  when 'aes-256-gcm'
    return 'A256GCM'
  else
    raise ArgumentError, "unhandled JOSE::JWE::ENC_AES_GCM cipher name: #{cipher_name.inspect}"
  end
end

#block_decrypt(aad_cipher_text_cipher_tag, cek, iv) ⇒ Object 



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 37

def block_decrypt(aad_cipher_text_cipher_tag, cek, iv)
  aad, cipher_text, cipher_tag = aad_cipher_text_cipher_tag
  cipher = OpenSSL::Cipher.new(cipher_name)
  cipher.decrypt
  cipher.key = cek
  cipher.iv = iv
  cipher.padding = 0
  cipher.auth_data = aad
  cipher.auth_tag = cipher_tag
  plain_text = cipher.update(cipher_text) + cipher.final
  return plain_text
end

#block_encrypt(aad_plain_text, cek, iv) ⇒ Object 



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 50

def block_encrypt(aad_plain_text, cek, iv)
  aad, plain_text = aad_plain_text
  cipher = OpenSSL::Cipher.new(cipher_name)
  cipher.encrypt
  cipher.key = cek
  cipher.iv = iv
  cipher.padding = 0
  cipher.auth_data = aad
  cipher_text = cipher.update(plain_text) + cipher.final
  return cipher_text, cipher.auth_tag
end

#next_cek ⇒ Object 



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 62

def next_cek
  return SecureRandom.random_bytes(cek_len)
end

#next_iv ⇒ Object 



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 66

def next_iv
  return SecureRandom.random_bytes(iv_len)
end

#to_map(fields) ⇒ Object 



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# File 'lib/jose/jwe/enc_aes_gcm.rb', line 18

def to_map(fields)
  return fields.put('enc', algorithm)
end