phpman > perldoc > Crypt::AuthEnc::EAX(3pm)

NAME
    Crypt::AuthEnc::EAX - Authenticated encryption in EAX mode

SYNOPSIS
     ### OO interface
     use Crypt::AuthEnc::EAX;

     # encrypt and authenticate
     my $ae = Crypt::AuthEnc::EAX->new("AES", $key, $iv);
     $ae->adata_add('additional_authenticated_data1');
     $ae->adata_add('additional_authenticated_data2');
     my $ct = $ae->encrypt_add('data1');
     $ct .= $ae->encrypt_add('data2');
     $ct .= $ae->encrypt_add('data3');
     my $tag = $ae->encrypt_done();

     # decrypt and verify
     my $ae = Crypt::AuthEnc::EAX->new("AES", $key, $iv);
     $ae->adata_add('additional_authenticated_data1');
     $ae->adata_add('additional_authenticated_data2');
     my $pt = $ae->decrypt_add('ciphertext1');
     $pt .= $ae->decrypt_add('ciphertext2');
     $pt .= $ae->decrypt_add('ciphertext3');
     my $tag = $ae->decrypt_done();
     die "decrypt failed" unless $tag eq $expected_tag;

     #or
     my $result = $ae->decrypt_done($expected_tag); # 0 or 1

     ### functional interface
     use Crypt::AuthEnc::EAX qw(eax_encrypt_authenticate eax_decrypt_verify);

     my ($ciphertext, $tag) = eax_encrypt_authenticate('AES', $key, $iv, $adata, $plaintext);
     my $plaintext = eax_decrypt_verify('AES', $key, $iv, $adata, $ciphertext, $tag);

DESCRIPTION
    EAX is a mode that requires a cipher, CTR and OMAC support and provides encryption and
    authentication. It is initialized with a random IV that can be shared publicly, additional
    authenticated data which can be fixed and public, and a random secret symmetric key.

EXPORT
    Nothing is exported by default.

    You can export selected functions:

      use Crypt::AuthEnc::EAX qw(eax_encrypt_authenticate eax_decrypt_verify);

FUNCTIONS
  eax_encrypt_authenticate
     my ($ciphertext, $tag) = eax_encrypt_authenticate($cipher, $key, $iv, $adata, $plaintext);

     # $cipher .. 'AES' or name of any other cipher with 16-byte block len
     # $key ..... AES key of proper length (128/192/256bits)
     # $iv ...... unique initialization vector (no need to keep it secret)
     # $adata ... additional authenticated data

  eax_decrypt_verify
     my $plaintext = eax_decrypt_verify($cipher, $key, $iv, $adata, $ciphertext, $tag);
     # on error returns undef

METHODS
  new
     my $ae = Crypt::AuthEnc::EAX->new($cipher, $key, $iv);
     #or
     my $ae = Crypt::AuthEnc::EAX->new($cipher, $key, $iv, $adata);

     # $cipher .. 'AES' or name of any other cipher with 16-byte block len
     # $key ..... AES key of proper length (128/192/256bits)
     # $iv ...... unique initialization vector (no need to keep it secret)
     # $adata ... additional authenticated data (optional)

  adata_add
     $ae->adata_add($adata);                        # can be called multiple times

  encrypt_add
     $ciphertext = $ae->encrypt_add($data);         # can be called multiple times

  encrypt_done
     $tag = $ae->encrypt_done();                    # returns $tag value

  decrypt_add
     $plaintext = $ae->decrypt_add($ciphertext);    # can be called multiple times

  decrypt_done
     my $tag = $ae->decrypt_done;           # returns $tag value
     #or
     my $result = $ae->decrypt_done($tag);  # returns 1 (success) or 0 (failure)

  clone
     my $ae_new = $ae->clone;

SEE ALSO
    *   CryptX, Crypt::AuthEnc::CCM, Crypt::AuthEnc::GCM, Crypt::AuthEnc::OCB

    *   <https://en.wikipedia.org/wiki/EAX_mode>