Method: Axlsx::MsOffCrypto#create_encryption_info

Defined in:
lib/axlsx/util/ms_off_crypto.rb

#create_encryption_info ⇒ String

Generates an encryption info structure

Returns:

  • (String) 


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# File 'lib/axlsx/util/ms_off_crypto.rb', line 105

def create_encryption_info
  header = [3, 0, 2, 0] # version
  # Header flags copy
  header.concat [0x24, 0, 0, 0] #flags -- VERY UNSURE ABOUT THIS STILL
  # header.concat [0, 0, 0, 0] #unused
  header.concat [0xA4, 0, 0, 0] #length
  # Header
  header.concat  [0x24, 0, 0, 0] #flags again
  # header.concat [0, 0, 0, 0] #unused again,
  header.concat [0x0E, 0x66, 0, 0] #alg id
  header.concat [0x04, 0x80, 0, 0] #alg hash id
  header.concat [key.size, 0, 0, 0] #key size
  header.concat [0x18, 0, 0, 0] #provider type
  # header.concat [0, 0, 0, 0] #reserved 1
  # header.concat [0, 0, 0, 0] #reserved 2
  header.concat [0xA0, 0xC7, 0xDC, 0x2, 0, 0, 0, 0]
  header.concat "Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)".bytes.to_a.pack('s*').bytes.to_a
  header.concat [0, 0] #null terminator

  #Salt Size
  header.concat [salt.bytes.to_a.size].pack('l').bytes.to_a
  #Salt
  header.concat salt.bytes.to_a.pack('c*').bytes.to_a
  # encryption verifier
  header.concat encrypted_verifier.bytes.to_a.pack('c*').bytes.to_a

  # verifier hash size -- MUST BE 32 bytes
  header.concat [verifier_hash.bytes.to_a.size].pack('l').bytes.to_a

  #encryption verifier hash
  header.concat encrypted_verifier_hash.bytes.to_a.pack('c*').bytes.to_a

  header.flatten!
  header.pack('c*')
end