checksum

Amazon S3 & Checksum

由 旧城冷巷雨未停 提交于 2019-11-27 10:58:29
问题 I try to verify the integrity of a file that was uploaded to a bucket but I don't find any information of this. In the file's headers, there is a "E-tag" but I think its not a md5 checksum. So, how can I check if the file that I uploaded on Amazon S3 is the same that I have on my computer ? Thanks. :) 回答1: If you are using the REST API to upload an object (up to 5GB) in a single operation, then you can add the Content-MD5 header in your PUT request. According the the S3 documentation for PUT,

Encrypting SQLite Database file in iPhone OS

由 房东的猫 提交于 2019-11-27 10:49:08
Any SQLite database on the iPhone is simply a file bundled with the application. It is relatively simple for anyone to extract this file and query it. What are your suggestions for encrypting either the file or the data stored within the database. Edit: The App is a game that will be played against other users. Information about a users relative strengths and weaknesses will be stored in the DB. I don't want a user to be able to jail-break the phone up their reputation/power etc then win the tournament/league etc (NB: Trying to be vague as the idea is under NDA). I don't need military

Windows equivalent of linux cksum command

由 我的梦境 提交于 2019-11-27 10:06:38
问题 I am looking for a way to compute crc checksum cross platform. cksum works on Linux, AIX, HP-UX Itanium, Solaris, is there a equivalent command of linux cksum in windows too? %cksum run.sh 1491301976 652 run.sh Note : no third party tool 回答1: In Windows (command prompt) you can use CertUtil, here is the syntax: CertUtil [Options] -hashfile InFile [HashAlgorithm] for syntax explanation type in cmd: CertUtil -hashfile -? example: CertUtil -hashfile C:\myFile.txt MD5 default is SHA1 it supports:

Oracle get checksum value for a data chunk defined by a select clause

由 纵饮孤独 提交于 2019-11-27 07:27:05
问题 Is there any method in SQL (Oracle) using which I can get something like: select checksum(select * from table) from table; 回答1: You can use DBMS_SQLHASH.GETHASH for this. The query results must be ordered and must not contain any LOBs, or the results won't be deterministic. select dbms_sqlhash.gethash(q'[select * from some_table order by 1,2]', digest_type => 1) from dual; Where digest_type 1 = HASH_MD4, 2 = HASH_MD5, 3 = HASH_SH1. That package is not granted to anyone by default. To use it,

How to check if Paramiko successfully uploaded a file to an SFTP server?

由 对着背影说爱祢 提交于 2019-11-27 07:26:47
问题 I use Paramiko to put a file to an SFTP server: import paramiko transport = paramiko.Transport((host, port)) transport.connect(username=username, password=password) sftp = paramiko.SFTPClient.from_transport(transport) sftp.put(local_path, remote_path) Now, I would like to check if it worked. The idea is that I compare the checksum of the local file and the remote one (that is located on the SFTP server). Does Paramiko functionality allows to do that? If it is the case, how exactly it works?

C Programming TCP Checksum

由 和自甴很熟 提交于 2019-11-27 06:20:29
问题 I have been having trouble doing the checksum for TCP for several days now. I have looked at many sources on the Internet but none of the examples that I have seen show you how to do the TCP checksum. I have also looked at the RFC document and still I am having trouble: Below is the code I am using to generate the checksum: unsigned short checksum(unsigned short * buffer, int bytes) { unsigned long sum = 0; unsigned short answer = 0; int i = bytes; while(i>0) { sum+=*buffer; buffer+=1; i-=2;

Methods to nail down 16 bit CRC/Checksum algorithm used by Windows CE executable?

由 北慕城南 提交于 2019-11-27 03:36:17
问题 I need to reverse engineer CRC/Checksum algorithm implemented by windows CE executable. Being propritory protocol, it does not say anything about CRC/checksum algorithm. However, There is console interface that reports correct/calculated checksum and I can construct my own messages with random bits if message protocol is correct: I have observed that, Changing single bit in message changes checksum bytes completely. Algorithm seems to be position dependent as I fed some single 1 bit messages

checksum udp calculation python

由 心已入冬 提交于 2019-11-27 02:57:25
问题 I'd like to calculate the checksum of an UDP header packet I want to send: packetosend = """60 00 00 00 00 24 3a 40 20 02 c0 a8 01 50 00 01 00 00 00 00 00 00 09 38 20 02 c0 a8 01 50 00 01 00 00 00 00 00 00 09 6f""" so I need to join this utf-16 (not a problem) and calculate the checksum of this specific packet. How can I do that? Thanks! EDIT: Yes it's an IPv6 header for an ICMPv6 packet, anyways what I would like to know is the formula, and how it works. I'll give another example with an

OpenCV 3.0 Trouble with Installation

由 China☆狼群 提交于 2019-11-27 01:42:47
问题 I need OpenCV3.0 since it supports some new functions which I need. I used the following code for installation (I had successfully installed OpenCV 2.4.9 using this code. But for OpenCV 3.0, while doing the cmake section, some error pops up due to mismatch of MD5 checksum) mkdir OpenCV cd OpenCV echo "Removing any pre-installed ffmpeg and x264" sudo apt-get -qq remove ffmpeg x264 libx264-dev echo "Installing Dependenices" sudo apt-get -qq install libopencv-dev build-essential checkinstall

Incremental Checksums

由 早过忘川 提交于 2019-11-26 23:09:57
问题 I am looking for a checksum algorithm where for a large block of data the checksum is equal to the sum of checksums from all the smaller component blocks. Most of what I have found is from RFCs 1624/1141 which do provide this functionality. Does anyone have any experience with these checksumming techniques or a similar one? 回答1: I have only used Adler/Fletcher checksums which work as you describe. There is a nice comparison of crypto++ hash/checksum implementations here. 回答2: If it's just a
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