Module: Net::IMAP::SASL::ScramAlgorithm

Included in:
ScramAuthenticator
Defined in:
lib/net/imap/sasl/scram_algorithm.rb

Overview

For method descriptions, see RFC5802 §2.2 and RFC5802 §3.

Instance Method Summary collapse

Instance Method Details

#auth_message ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 35

def auth_message
  [
    client_first_message_bare,
    server_first_message,
    client_final_message_without_proof,
  ]
    .join(",")
end

#client_key ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 48

def client_key;       HMAC(salted_password, "Client Key") end

#client_proof ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 53

def client_proof;     XOR(client_key, client_signature)   end

#client_signature ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 51

def client_signature; HMAC(stored_key, auth_message)      end

#H(str) ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 24

def H(str) digest.digest str end

#Hi(str, salt, iterations) ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 13

def Hi(str, salt, iterations)
  length = digest.digest_length
  OpenSSL::KDF.pbkdf2_hmac(
    str,
    salt:       salt,
    iterations: iterations,
    length: length,
    hash: digest,
  )
end

#HMAC(key, data) ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 26

def HMAC(key, data) OpenSSL::HMAC.digest(digest, key, data) end

#Normalize(str) ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 11

def Normalize(str) SASL.saslprep(str) end

#salted_password ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 44

def salted_password
  Hi(Normalize(password), salt, iterations)
end

#server_key ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 49

def server_key;       HMAC(salted_password, "Server Key") end

#server_signature ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 52

def server_signature; HMAC(server_key, auth_message)      end

#stored_key ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 50

def stored_key;       H(client_key)                       end

#XOR(str1, str2) ⇒ Object 



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# File 'lib/net/imap/sasl/scram_algorithm.rb', line 28

def XOR(str1, str2)
  str1.unpack("C*")
    .zip(str2.unpack("C*"))
    .map {|a, b| a ^ b }
    .pack("C*")
end