{
    "mode": "perldoc",
    "parameter": "Crypt::Mode::OFB",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AMode%3A%3AOFB/json",
    "generated": "2026-06-10T17:31:48Z",
    "synopsis": "use Crypt::Mode::OFB;\nmy $m = Crypt::Mode::OFB->new('AES');\n#(en|de)crypt at once\nmy $ciphertext = $m->encrypt($plaintext, $key, $iv);\nmy $plaintext = $m->decrypt($ciphertext, $key, $iv);\n#encrypt more chunks\n$m->startencrypt($key, $iv);\nmy $ciphertext = $m->add('some data');\n$ciphertext .= $m->add('more data');\n#decrypt more chunks\n$m->startdecrypt($key, $iv);\nmy $plaintext = $m->add($someciphertext);\n$plaintext .= $m->add($moreciphertext);",
    "sections": {
        "NAME": {
            "content": "Crypt::Mode::OFB - Block cipher mode OFB [Output feedback]\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "use Crypt::Mode::OFB;\nmy $m = Crypt::Mode::OFB->new('AES');\n\n#(en|de)crypt at once\nmy $ciphertext = $m->encrypt($plaintext, $key, $iv);\nmy $plaintext = $m->decrypt($ciphertext, $key, $iv);\n\n#encrypt more chunks\n$m->startencrypt($key, $iv);\nmy $ciphertext = $m->add('some data');\n$ciphertext .= $m->add('more data');\n\n#decrypt more chunks\n$m->startdecrypt($key, $iv);\nmy $plaintext = $m->add($someciphertext);\n$plaintext .= $m->add($moreciphertext);\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "This module implements OFB cipher mode. NOTE: it works only with ciphers from CryptX\n(Crypt::Cipher::NNNN).\n",
            "subsections": []
        },
        "METHODS": {
            "content": "new\nmy $m = Crypt::Mode::OFB->new($name);\n#or\nmy $m = Crypt::Mode::OFB->new($name, $cipherrounds);\n\n# $name ............ one of 'AES', 'Anubis', 'Blowfish', 'CAST5', 'Camellia', 'DES', 'DESEDE',\n#                    'KASUMI', 'Khazad', 'MULTI2', 'Noekeon', 'RC2', 'RC5', 'RC6',\n#                    'SAFERP', 'SAFERK128', 'SAFERK64', 'SAFERSK128', 'SAFERSK64',\n#                    'SEED', 'Skipjack', 'Twofish', 'XTEA', 'IDEA', 'Serpent'\n#                    simply any <NAME> for which there exists Crypt::Cipher::<NAME>\n# $cipherrounds ... optional num of rounds for given cipher\n\nencrypt\nmy $ciphertext = $m->encrypt($plaintext, $key, $iv);\n\ndecrypt\nmy $plaintext = $m->decrypt($ciphertext, $key, $iv);\n\nstartencrypt\n$m->startencrypt($key, $iv);\n\nstartdecrypt\n$m->startdecrypt($key, $iv);\n\nadd\n# in encrypt mode\nmy $plaintext = $m->add($ciphertext);\n\n# in decrypt mode\nmy $ciphertext = $m->add($plaintext);\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "*   CryptX, Crypt::Cipher\n\n*   Crypt::Cipher::AES, Crypt::Cipher::Blowfish, ...\n\n*   <https://en.wikipedia.org/wiki/Blockciphermodeofoperation#Outputfeedback.28OFB.29>\n",
            "subsections": []
        }
    },
    "summary": "Crypt::Mode::OFB - Block cipher mode OFB [Output feedback]",
    "flags": [],
    "examples": [],
    "see_also": []
}