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Class: Net::IMAP::CramMD5Authenticator

Relationships & Source Files
Inherits: Object
Defined in: lib/net/imap/authenticators/cram_md5.rb

Overview

Authenticator for the “CRAM-MD5” SASL mechanism, specified in RFC2195. See #authenticate.

Deprecated

CRAM-MD5 is obsolete and insecure. It is included for compatibility with existing servers. draft-ietf-sasl-crammd5-to-historic recommends using SCRAM-* or PLAIN protected by TLS instead.

Additionally, RFC8314 discourage the use of cleartext and recommends TLS version 1.2 or greater be used for all traffic. With TLS CRAM-MD5 is okay, but so is PLAIN

Class Method Summary

Instance Method Summary

Constructor Details

.new(user, password, warn_deprecation: true, **_ignored) ⇒ CramMD5Authenticator (private)

[ GitHub ] 

  


# File 'lib/net/imap/authenticators/cram_md5.rb', line 24



def initialize(user, password, warn_deprecation: true, **_ignored)
  if warn_deprecation
    warn "WARNING: CRAM-MD5 mechanism is deprecated." # TODO: recommend SCRAM
  end
  require "digest/md5"
  @user = user
  @password = password
end


  







Instance Method Details



  

    #hmac_md5(text, key)   (private)
  

  [ GitHub ]


  

  


# File 'lib/net/imap/authenticators/cram_md5.rb', line 33



def hmac_md5(text, key)
  if key.length > 64
    key = Digest::MD5.digest(key)
  end

  k_ipad = key + "\0" * (64 - key.length)
  k_opad = key + "\0" * (64 - key.length)
  for i in 0..63
    k_ipad[i] = (k_ipad[i].ord ^ 0x36).chr
    k_opad[i] = (k_opad[i].ord ^ 0x5c).chr
  end

  digest = Digest::MD5.digest(k_ipad + text)

  return Digest::MD5.hexdigest(k_opad + digest)
end


  








  

    #process(challenge)  
  

  [ GitHub ]


  

  


# File 'lib/net/imap/authenticators/cram_md5.rb', line 17



def process(challenge)
  digest = hmac_md5(challenge, @password)
  return @user + " " + digest
end