![\"\"](\"http:\/\/www.nicau.ro\/wp-content\/uploads\/2021\/08\/CAST-128.png\")
<\/a><\/p>\nThis symmetric-key block cipher comes in handy as it allows a variable key size of 40 to 128 bits and a block size of 64 bits. According to RFC2144<\/a> there is no difference between CAST-128 and CAST5, these are two names of a same thing.<\/p>\n \u00a0<\/p>\n Even if widely regarded unsafe, some of us still have reasons for using a smaller key. Other people should go for the full 128 bit key.<\/p>\n We will discuss how you encrypt a text with openssl<\/b> and decrypt it from php<\/b>, along with a couple of subtleties for the beginner crypto user. For this example we will use CAST-128 with a 64 bit key.<\/p>\n Common questions for block ciphers:<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" \u00a0 This symmetric-key block cipher comes in handy as it allows a variable key size of 40 to 128 bits and a block size of 64 bits. According to RFC2144 there is no difference between CAST-128 and CAST5, these are two names of a same thing. \u00a0 Even if widely regarded unsafe, some of us […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[13,14],"tags":[],"_links":{"self":[{"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/posts\/341"}],"collection":[{"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=341"}],"version-history":[{"count":32,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/posts\/341\/revisions"}],"predecessor-version":[{"id":375,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=\/wp\/v2\/posts\/341\/revisions\/375"}],"wp:attachment":[{"href":"https:\/\/www.nicau.ro\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=341"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=341"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nicau.ro\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=341"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\n
OpenSSL<\/h3>\n
\n
MacBook-Pro:~ alexandru$ openssl enc -K \"ABCDABEFAABBCCDD\" -cast -e -in input.txt -out output.base64 -iv 0000000000000000 -nosalt -base64 -p
hex string is too short, padding with zero bytes to length
key=ABCDABEFAABBCCDD0000000000000000
iv =0000000000000000
MacBook-Pro:~ alexandru$ cat output.base64
M11VwvXjPq5sWTrZr4KNDA==<\/pre>\nPHP<\/h3>\n
\n
$method = \"CAST5-CBC\";
$secret_key = hex2bin(\"ABCDABEFAABBCCDD\"); \/\/hex string transformed into binary
$encrypted_msg = \"M11VwvXjPq5sWTrZr4KNDA==\"; \/\/note, this is base64
$raw_encrypted_msg = base64_decode($encrypted_msg);
$iv = hex2bin(\"0000000000000000\"); \/\/hex string transformed into binary
if (is_bool($decrypt_result = openssl_decrypt($raw_encrypted_msg, $method, $secret_key, OPENSSL_RAW_DATA, $iv)))
echo \"FAILED!\";
else
echo $decrypt_result;<\/pre>\nTricks<\/h3>\n
\n
openssl enc -K \"ABCDABEFAABBCCDD\" -cast -e -in input.txt -out output.base64 -iv 0000000000000000 -nosalt -base64
openssl enc -K \"ABCDABEFAABBCCDD\" -cast -d -in output.base64 -out output.dec -iv 0000000000000000 -nosalt -base64 -nopad<\/pre>\nReferences<\/h3>\n
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