java - Bouncy Castle : Detached Enveloped Signature Changes at Every Run -


i following post generating , verifying digital signature. signed data remains constant @ runs detached enveloped signature varies @ every run. how same text generates different detached enveloped signature?

to make comments answer...

there 2 major reasons why signatures of same data same private key may vary.

signature algorithm induced variations

certain signature algorithms, foremost dsa , ecdsa, explicitly base signature creation on randomly chosen value k. "randomness" required, the entropy, secrecy, , uniqueness of random signature value k is critical. critical violating 1 of 3 requirements can reveal entire private key attacker. using same value twice (even while keeping k secret), using predictable value, or leaking few bits of k in each of several signatures, enough break algorithm. requirement can fulfilled random k or k built in deterministic way guarantees entropy, secrecy, , uniqueness, cf. rfc 6967.

the op, though, refers code uses rsa. algorithm not require such random parameter (even though padding schemes may include randomness).

signature attribute induced variations

another reason variations signed data include more document data.

when talking "signatures", people not merely mean signing process byte array output instead signature container according cms standard.

there may multiple individual signatures in such container, , each of them may have number of unsigned or signed attributes. name "signed attributes" implies, signature value calculation includes these attributes, too.

very these signed attributes include signing time. signing time varies in different signing runs, actual signature value varies, too.

the op uses cms signature containers. thus, cause why op's signatures vary.


Comments

Post a Comment

Popular posts from this blog

basic authentication with http post params android -

i doing basic authentication passing username , password , using basicnamevaluepair sending post params response service. my method: public stringbuilder callservicehttppost(string username, string password, string type) { // create new httpclient , post header httpclient httpclient = new defaulthttpclient(); httppost httppost = new httppost(webservice + type); httpresponse response = null; stringbuilder total = new stringbuilder(); try { url url = new url(webservice + type); /*string base64encodedcredentials = base64.encodetostring((username + ":" + password).getbytes(), base64.url_safe | base64.no_wrap);*/ string base64encodedcredentials = "basic " + base64.encodetostring( (username + ":" + password).getbytes(), base64.no_wrap); httppost.setheader("auth...
Read more

vb.net - Virtual Keyboard commands -

i wondering difference between virtual these keyboard commands is: keyeventf_extendedkey , keyeventf_keyup is. everywhere have looked gives me description based off integers , not want know each of them does. you've tagged question vb.net, these have nothing @ vb.net. they're constants defined in windows header files, use win32 api functions. as far difference, can't tell looking @ values. individual values not particularly important, that's why named identifiers used. what's important used , documentation functions tells mean. the first one, keyeventf_extendedkey , used keybdinput structure (which used along e.g. sendinput function) pass information synthesized keyboard input. if flag used, means scan code should interpreted extended key. technically, means scan code preceded prefix byte value 224 (&he0 in hexadecimal notation). the second one, keyeventf_keyup , 1 of flags available use structure. means key being released (going up)...
Read more

How to get multiresult with multicondition in Sql Server -

i need solve this. hopefully can giving me advices. for sample, i've got data : proclib.march 1 first 10 rows flight date depart orig dest miles boarded capacity ----------------------------------------------------------------- 114 01mar94 7:10 lga lax 2475 172 210 202 01mar94 10:43 lga ord 740 151 210 219 01mar94 9:31 lga lon 3442 198 250 622 01mar94 12:19 lga fra 3857 207 250 132 01mar94 15:35 lga yyz 366 115 178 271 01mar94 13:17 lga par 3635 138 250 302 01mar94 20:22 lga 229 105 180 114 02mar94 7:10 lga lax 2475 119 210 202 02mar94 10:43 lga ord 740 120 210 219 02mar94 9:31 lga lon 344...
Read more