perl - How can I decrypt Blowfish ciphertext with a salted header? -


i have ciphertext has been encrypted using perl's crypt::cbc module wish decrypt elsewhere.

the ciphertext generated using 'simple' version of crypt::cbc constructor, is:

use crypt::cbc; $cipher = crypt::cbc->new( -key    => 'my secret key',                            -cipher => 'blowfish'                           );

from reading man page, method of construction take simple string key , random salt generate iv & literal key use encryption, embed header salt.

"salt" -- combine passphrase 8-byte random value generate both block cipher key , iv provided passphrase. salt appended beginning of data stream allowing decryption regenerate both key , iv given correct passphrase. method compatible current versions of openssl.

i need decrypt ciphertext on platform supports cbc decryption given ciphertext, literal key & iv. attempt generate literal key, iv & salt, used crypt::cbc generate values so:

my $crypt = new crypt::cbc(-key => 'my secret key', -cipher => 'blowfish'); $out = $crypt->decrypt($ciphertext); $literal_key = $crypt->key(); $iv = $crypt->iv(); $salt = $crypt->salt();

the decryption here correct, i've been unable use generated literal key & iv decrypt cipher; produces rubbish:

my $crypt2 = new crypt::cbc(     -literal_key => 1,     -key => $literal_key,     -cipher => 'blowfish',     -iv => $iv,     -header => 'none'); $rubbish - $crypt2->decrypt($ciphertext);

i can't provide literal key , use salted header i'm lost next move.

how can decrypt text?

edit: target system not running perl, have been able generate identical value in $rubbish above, i'm sure it's using same algorithm (cbc, blowfish) decipher.

to decrypt stream, first need remove header added crypt::cbc's "salt" mode. header consists of 8 characters salted__ followed 8 bytes of salt data.

in perl, should it:

my $crypt2 = new crypt::cbc(     -literal_key => 1,     -key => $literal_key,     -cipher => 'blowfish',     -iv => $iv,     -header => 'none'); $cleartext = $crypt2->decrypt(substr($ciphertext, 16));

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