xcc | Toy C compiler for x86-64/aarch64/wasm | Compiler library
kandi X-RAY | xcc Summary
kandi X-RAY | xcc Summary
Toy C compiler for x86-64/aarch64/wasm
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of xcc
xcc Key Features
xcc Examples and Code Snippets
Community Discussions
Trending Discussions on xcc
QUESTION
I am trying encrypting in JS front end and decrypt in python backend using AES GCM cryptographic algorithm. I am using Web cryptography api for JS front end and python cryptography library for python backend as cryptographic library. I have fixed the IV for now in both side. I have implemented encryption-decryption code in both side, they work on each side. But I think the padding is done differently, can't seem to figure out how the padding is done in web cryptography api. Here is the encryption and decryption for the python backend:
...ANSWER
Answered 2021-Jun-14 at 18:01GCM is a stream cipher mode and therefore does not require padding. During encryption, an authentication tag is implicitly generated, which is used for authentication during decryption. Also, an IV/nonce of 12 bytes is recommended for GCM.
The posted Python code unnecessarily pads and doesn't take the authentication tag into account, unlike the JavaScript code, which may be the main reason for the different ciphertexts. Whether this is the only reason and whether the JavaScript code implements GCM correctly, is difficult to say, since the getMessageEncoding()
method was not posted, so testing this was not possible.
Also, both codes apply a 16 bytes IV/nonce instead of the recommended 12 bytes IV/nonce.
Cryptography offers two possible implementations for GCM. One implementation uses the architecture of the non-authenticating modes like CBC. The posted Python code applies this design, but does not take authentication into account and therefore implements GCM incompletely. A correct example for this design can be found here.
Cryptography generally recommends the other approach for GCM (s. the Danger note), namely the AESGCM
class, which performs implicit authentication so that this cannot be accidentally forgotten or incorrectly implemented.
The following implementation uses the AESGCM
class (and also takes into account the optional additional authenticated data):
QUESTION
I need some help with MarkLogic, XQuery & corb,
I have millions of documents in the database, I'm trying to write the XQuery to saved the matched uris.
urisVersions.xqy
...ANSWER
Answered 2021-Jun-10 at 17:42Configure the job with the PROCESS-TASK
option to use the com.marklogic.developer.corb.ExportBatchToFileTask
class, which will write the results of each process module invocation to an output file. You can configure where to write the file and the filename with EXPORT-FILE-NAME
and EXPORT-FILE-DIR
options. If you don't configure the EXPORT-FILE-DIR and just give it a filename with EXPORT-FILE-NAME it writes relative from where CoRB is launched.
QUESTION
I want to enable ssl for localhost, with nginx and a self signed certificate. I want to do this because I'm putting nginx as a reverse proxy in front of an application that redirects with https, and I don't want to modify the application
I have generated the certificate with the following command:
...ANSWER
Answered 2021-Jun-03 at 14:12You must add the certificates inside server
block on nginx.conf
:
QUESTION
Lately I have started implementing TLS for the sport as a fun project and I'm currently trying to self make and send locally a client hello TLS packet (a minimal one).
When observed via the loopback interface in Wireshark it appears as pure data instead of a tls layer with all of the various fields and after lots of trying I decided to ask here the following questions:
- What's the difference between my self made packet and a real TLS client hello one?
- How does Wireshark selectively makes one appear as a TLS layered instead of pure data, is there an identifier field in the packet that declares it as pure data or a TLS layered one?
- How can I make my packet to appear as a client hello TLS packet instead of pure data?
Here is my server and client that send basically my c code output (remember that they are not made for real TLS handling but just to show the packet in Wireshark):
server.py
...ANSWER
Answered 2021-Jun-01 at 21:45For starters, the TLS length field is wrong. Wireshark's TCP dissector indicates that the TCP payload length is 78 bytes; yet the TLS length is 165 (0x00a5), and thus can't be correct. Also, the handshake length is wrong too. Try changing this:
QUESTION
I have the following data from a datagram message received by UDP socket:
...ANSWER
Answered 2021-May-19 at 19:55each float is 4 bytes of data (typically... not always... again you need to consult the docs for whatever p[ayload you need)
but assuming that /13/raw
is easy enough for you and the rest is what you need to decode
if we assume that \x00
is some sort of delimiter we are left with the bytestring as follows
QUESTION
I wrote a shellcode in C that pops a messagebox. I have compiled two variations of it. One says "Hello World!" (shellcodeA) and the other one says "Goodbye World!" (shellcodeB).
...ANSWER
Answered 2021-May-19 at 13:43I don't know where you see the value 0x119, but BYTE bootstrap[12]
is a BYTE
array.
So assigning bootstrap[i++] = sizeof(bootstrap) + shellcodeALength - i - 4;
will store the lowest byte of the expression in bootstrap[i++]
and ignore the rest, hence can never go above 255.
You probably want something like this instead:
QUESTION
I have to send commands to some device with the hexadecimal format.
I have succeeded to send hex commands with "\xAA\xBB\xCC\xDD\xEE"
and "\xAA\xBB\xCC%c\xEE"
with %c
containing a certain decimal value.
But I can't send 00
value like "\xAA\xBB\xCC0x00\xEE"
.
I've seen many topic on this, but no solution fits my need. I tried different things, like:
...ANSWER
Answered 2021-May-07 at 07:44As @MikeCAT and @Remy Lebeau said : sprintf(char_array, "\xAA\xBB\xCC%c\xEE", '0');
work.
The issue was that later in my code I have a strlen(char_array)
which returned :
6 for sprintf(char_array, "\xAA\xBB\xCC\xDD\xEE", 22);
and
4 for sprintf(char_array, "\xAA\xBB\xCC%c\xEE", 0);
So for now i will fix the size at 6. Thanks for your help.
QUESTION
I am looking for an efficient way to check for leading zeros in a bytes object. The check should run also for nibbles. Right now I am checking bytes only, with the search_zeros
function; where the input parameters are: n
: number of leading zeros to check for, and inp_bytes
the bytes object:
ANSWER
Answered 2021-Apr-23 at 15:32I would avoid constructing check_bytes
, since that will consume unnecessary storage in memory when n is very large. So my approach would be to use a loop or an equivalent comprehension.
Additional considerations:
- I assume you don't want an exception if the string is too short, so I added some logic for that case. I think
len(inp_bytes)
is a constant time operation, so this should be fast. - I'm using the fact that a byte
y
is "True" when non-zero, I'm pretty sure that's as fast a way as any, but benchmarking could confirm that if you're really after all the nanoseconds you can save. - You can use bitwise operations to test the last nibble if
n
is odd. Note that in Python, bitwise operations are defined on bytes, but not in sequences of bytes.b'\xf0'
is a sequence of bytes, so& b'\xf0'
yields an exception.b'\xf0'[0]
is the first (and only) byte in that sequence, and that's accepted as an operand of&
. - EDIT: you clarified in the comments you only want
inp_bytes
returned if the number of leading zeros exactly equalsn
--logic added to check that the next nibble is non-zero.
With all that in mind, this is my solution:
QUESTION
I tried to extract only the English words from the following list:
...ANSWER
Answered 2021-Apr-03 at 14:08if you know what you want to search , just search .
QUESTION
I have a Python string of bytes data. An example string looks like this:
...ANSWER
Answered 2021-Apr-05 at 14:48I assume that you have python-like string representation in variable s
:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install xcc
cpp: Preprocessor
cc1: C compiler
as: Assembler
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page