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>