Crypt::AuthEnc::CCM(3)
NAME
Crypt::AuthEnc::CCM - Authenticated encryption in CCM mode
SYNOPSIS
### OO interface use Crypt::AuthEnc::CCM; # encrypt and authenticate my $ae = Crypt::AuthEnc::CCM->new("AES", $key, $iv, $adata, $tag_len, $pt_len); 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::CCM->new("AES", $key, $iv, $adata, $tag_len, $pt_len); 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::CCM qw(ccm_encrypt_authenticate ccm_decrypt_verify); ($ciphertext, $tag) = ccm_encrypt_authenticate('AES', $key, $nonce, $adata, $tag_len, $plaintext); $plaintext = ccm_decrypt_verify('AES', $key, $nonce, $adata, $ciphertext, $tag);
DESCRIPTION
CCM is a encrypt+authenticate mode that is centered around using AES (or any 16-byte cipher) as a primitive. Unlike EAX and OCB mode, it is only meant for packet mode where the length of the input is known in advance.
EXPORT
Nothing is exported by default. You can export selected functions: use Crypt::AuthEnc::CCM qw(ccm_encrypt_authenticate ccm_decrypt_verify);
FUNCTIONS
ccm_encrypt_authenticate my ($ciphertext, $tag) = ccm_encrypt_authenticate($cipher, $key, $nonce, $adata, $tag_len, $plaintext); # $cipher .. 'AES' or name of any other cipher with 16-byte block len # $key ..... key of proper length (e.g. 128/192/256bits for AES) # $nonce ... unique nonce/salt (no need to keep it secret) # $adata ... additional authenticated data # $tag_len . required length of output tag CCM parameters should follow <http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38c.pdf> # tag length: 4, 6, 8, 10, 12, 14, 16 (reasonable minimum is 8) # nonce length: 7, 8, 9, 10, 11, 12, 13 (if you are not sure, use 11) # BEWARE nonce length determines max. enc/dec data size: max_data_size = 2^(8*(15-nonce_len)) ccm_decrypt_verify my $plaintext = ccm_decrypt_verify($cipher, $key, $nonce, $adata, $ciphertext, $tag); # on error returns undef
METHODS
new my $ae = Crypt::AuthEnc::CCM->new($cipher, $key, $nonce, $adata, $tag_len, $pt_len); # $cipher .. 'AES' or name of any other cipher with 16-byte block len # $key ..... key of proper length (e.g. 128/192/256bits for AES) # $nonce ... unique nonce/salt (no need to keep it secret) # $adata ... additional authenticated data # $tag_len . required length of output tag # $pt_len .. expected length of plaintext/ciphertext to encrypt/decrypt encrypt_add $ciphertext = $ae->encrypt_add($data); # can be called multiple times encrypt_done my $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
o CryptX(3), Crypt::AuthEnc::EAX(3), Crypt::AuthEnc::GCM(3), Crypt::AuthEnc::OCB(3) o <https://en.wikipedia.org/wiki/CCM_mode> perl v5.30.3 2022-01-07 Crypt::AuthEnc::CCM(3)
cryptx 0.76.0 - Generated Mon Feb 14 05:49:05 CST 2022