Module: Fernet::Encryption

Defined in:
lib/fernet/encryption.rb

Overview

Internal: Encapsulates encryption and signing primitives

Constant Summary collapse

AES_BLOCK_SIZE = 
16.freeze

Class Method Summary collapse

Class Method Details

.decrypt(opts) ⇒ Object

Internal: Decrypts the provided ciphertext using a AES-128-CBC cipher with a

the provided IV and encryption key

opts - a hash containing

  • ciphertext - encrypted message

  • key - encryption key used to encrypt the message

  • iv - initialization vector used in the ciphertext’s cipher

Examples

ciphertext, iv = Fernet::Encryption.encrypt(
  message: 'this is a secret', key: encryption_key
)

Returns a two-element array containing the ciphertext and the random IV



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# File 'lib/fernet/encryption.rb', line 52

def self.decrypt(opts)
  decipher = OpenSSL::Cipher.new('AES-128-CBC')
  decipher.decrypt
  decipher.iv  = opts[:iv]
  decipher.key = opts[:key]
  decipher.update(opts[:ciphertext]) + decipher.final
end

.encrypt(opts) ⇒ Object

Internal: Encrypts the provided message using a AES-128-CBC cipher with a

random IV and the provided encryption key

opts - a hash containing

  • message - the message to encrypt

  • key - the encryption key

  • iv - override for the random IV, only used for testing

Examples

ciphertext, iv = Fernet::Encryption.encrypt(
  message: 'this is a secret', key: encryption_key
)

Returns a two-element array containing the ciphertext and the random IV



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# File 'lib/fernet/encryption.rb', line 23

def self.encrypt(opts)
  cipher = OpenSSL::Cipher.new('AES-128-CBC')
  cipher.encrypt
  iv = opts[:iv] || cipher.random_iv
  cipher.iv  = iv
  cipher.key = opts[:key]
  ciphertext = ""
  if opts[:message] && !opts[:message].empty?
    ciphertext += cipher.update(opts[:message])
  end
  ciphertext += cipher.final
  [ciphertext, iv]
end

.hmac_digest(key, bytes) ⇒ Object

Internal: Creates an HMAC signature (sha356 hashing) of the given bytes

with the provided signing key

key - the signing key bytes - blob of bytes to sign

Returns the HMAC signature as a string



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# File 'lib/fernet/encryption.rb', line 67

def self.hmac_digest(key, bytes)
  OpenSSL::HMAC.digest('sha256', key, bytes)
end