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  • If You Include the Groovy Editor...

    - by Geertjan
    ...in a NetBeans RCP application, what additional JARs will you need to include for the Groovy Editor to work? Leaving aside the debate on the current state & quality of the NetBeans Groovy Editor, so, assuming you need the Groovy support that the NetBeans Groovy Editor provides, you would check the Groovy Editor checkbox in the Project Properties dialog of your application: As you can see, however, the Groovy Editor depends on other modules, some of which, in turn, depend on yet other modules, and so on. So, I clicked the "Resolve" button above and then created a ZIP distribution, to see which additional JARs had been included. Until that point, I had only been using the "platform" cluster, which means that absolutely everything found in the ZIP's "ide" cluster and "java" cluster have only been included so that the Groovy Editor could be included, i.e., all thanks to clicking the "Resolve" button above. Let's first look at what that means for the "java" cluster: That's not so bad and kind of a side effect of Groovy being Java, i.e., a lot of Java functionality is needed. Now let's look at the "ide" cluster: So, in answer to the original question, if all you want in your NetBeans Platform application, in terms of editor functionality, is the Groovy Editor, then you have a pretty high price to pay. At the very least, I would have assumed that the project support JARs and the debugger support JARs would not be so tightly coupled with the Groovy Editor. That would be a cool thing to separate out from the editor support.

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  • Hyper-V Live Migration across Sites!

    - by Ryan Roussel
    One of the great sessions I sat in on at Tech Ed this week was stretching a Windows 2008 R2 Hyper-V  Failover Cluster across sites.  With this ability, you could actually implement a Hyper-V cluster where you could migrate or even Live Migrate VMs across sites.   With this area’s propensity for Hurricanes, this will be a very popular topic for me over the next few months. While this technology is possible today, it’s also very complicated and can be very expensive to implement.    First your WAN connection has to support the ability to trunk your VLAN across both sites in order to Live Migrate.  This means you can’t use a Layer 3 routed connection like MPLS.  It has to be a Metro Ethernet connection or "Dark Fiber”.  Dark Fiber is unused Fiber already in the ground that can be leased from  various providers. Both of these connections would allow you to trunk layer 2 across your WAN.  Cisco does have the ability to trunk layer 2 across a routed connection by muxing the traffic but this is only available in their Nexus product line which has a very steep price tag.   If you are stuck with MPLS or the like and Nexus switching is not a realistic possibility, you will have to implement a multi-subnet cluster in which case Live Migration won’t be possible.  However you can still failover VMs to the remote site with some planning and manual intervention.  The consideration here is that the VMs will be on a different subnet once migrated, so you will have to change the IP addressing of your VMs.  This also has ramifications with DNS and Name resolution to control your down time.  DHCP with Reservations for your VMs is the preferred method to achieve the IP changes as this will automate that part of the process.   Secondly, you will have to have  a mechanism to replicate your storage across both sites.  Many SAN vendors natively support hardware based synchronous and asynchronous replication.  Some even support cluster shared volumes which were introduced in 2008 R2.   If your SANs do not support this natively, there are alternative file based replication products either software based like Double Take or hardware appliance like EMC.  Be sure to check with your vendor on the support of Disk majority if you’re replicating your quorum disk between SANs.   The last consideration is the ability to maintain quorum for your cluster.  If your replication provider does not support Disk Majority through replication, you will have to explore Node Majority with File Share Witness.  This will affect your design as a 3 node cluster with 1 node at the remote site and FSW at the production site would not have the ability to maintain quorum if the production site was lost. MS best practice for this would be to implement an even node cluster with 2 nodes at  each site and the FSW at a third site.   And there you have it.  While some considerations and research goes into implementing this solution, even a multi-subnet solution would be invaluable to organizations in the implementations of “warm” DR sites.

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  • Quickly compute added and removed lines

    - by Philippe Marschall
    I'm trying to compare two text files. I want to compute how many lines were added and removed. Basically what git diff --stat is doing. Bonus points for not having to store the entire file contents in memory. The approach I'm currently having in mind is: read each line of the old file compute a hash (probably MD5 or SHA-1) for each line store the hashes in a set do the same for each line in the new file every hash from the old file set that's missing in the new file set was removed every hash from the new file set that's missing in the old file set was added I'll probably want to exclude empty and all white space lines. There is a small issue with duplicated lines. This can either be solved by additionally storing how often a hash appears or comparing the number of lines in the old and new file and adjust either the added or removed lines so that the numbers add up. Do you see room for improvements or a better approach?

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  • Homebrew large data cluster access for 2 user levels?

    - by Yegor
    The title probably makes little sense, so here is an example. I have a file hosting site, that serves a large amount of semi-randomly accessed files. The setup is as follows: High horsepower front-end +DB server that also does encoding for files that need encoding Fresh file server, which stores newly uploaded content, thats probably (and usually) rapidly accessible, which has 500GB of raided SSD storage, that can push over 3GBit of traffic. 3 cheap node servers, containing 2 x 750GB SATA drives in raid1, where files older than 2 weeks are archived, from the SSD server (mentioned above). Files on each server are accessed via subdomains (via modsec) in a straight forward fashion (server1.domain.com, server2.domain.com, etc) Where I have the problem is this. I introduced a "premium" service where people pay a small fee every month, and get ad-free, quick accesses to stuff on the site. Once they are logged in, they access same files via premium.server1.domain.com via a different modsec script, with a different pass phrase. That all works fine and dandy.... except the cheap node servers are all IO bound, so accessing the files on them via a different, unsaturated network makes no difference, since it cannot read off the drive fast enough. What would be a good way to make files on the site be accessible via 2 different network routes, 1 of which will be saturated (the "free network") while all other files are on an un-saturated "premium" network?

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  • How to make AD highly available for applications that use it as an LDAP service

    - by Beaming Mel-Bin
    Our situation We currently have many web applications that use LDAP for authentication. For this, we point the web application to one of our AD domain controllers using the LDAPS port (636). When we have to update the Domain Controller, this has caused us issues because one more web application could depend on any DC. What we want We would like to point our web applications to a cluster "virtual" IP. This cluster will consist of at least two servers (so that each cluster server could be rotated out and updated). The cluster servers would then proxy LDAPS connections to the DCs and be able to figure out which one is available. Questions For anyone that has had experience with this: What software did you use for the cluster? Any caveats? Or perhaps a completely different architecture to accomplish something similar?

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  • Is it safe StringToHash() to use in Unity?

    - by Sebastian Krysmanski
    I'm currently browsing through the Unity tutorials and saw that they're recommending to use Animator.StringToHash("some string") to created unique ids for animation properties (see here). Since I'm a programmer, to me the word "hash" doesn't represents something unique. Like the Java documentation for hashValue() states: It is not required that if two objects are unequal [...], then calling the hashCode method on each of the two objects must produce distinct integer results. So, according to this (and my definition of "hash"), two strings may have the same hash value. (You can also argue that there are an infinite number of possible strings but only 2^32 possible int values.) So, is there a possibility that StringToHash() will give me an id that actually belongs to another property (than the one I requested the hash for)?

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  • ArchBeat Link-o-Rama for November 13, 2012

    - by Bob Rhubart
    This week on the OTN Solution Architect Homepage Make time to check out this week's features on the OTN Solution Architect Homepage, including: SOA Practitioner Guide: Identifying and Discovering Services Setting Up, Configuring, and Using an Oracle WebLogic Server Cluster OTN ArchBeat Podcast: Are You Future Proof (Conclusion) Keynote: New Paradigms for Application Architecture: From Applications to IT Services I this keynote address from the SOA, Cloud, and Service Technology Symposium, Anne Thomas Manes highlights the importance of adapting to the current trend marked by the convergence of mobile, social and cloud, moving away from app-centric design to service-based solutions. New Solaris Cluster! | Jeff Victor "Oracle Solaris Cluster 4.1 offers both High Availability (HA) and also Scalable Services capabilities," explains Jeff Victor. "HA delivers automatic restart of software on the same cluster node and/or automatic failover from a failed node to a working cluster node. Software and support is available for both x86 and SPARC systems." You'll find download links and other resources in Jeff's short post. ADF BC View Accessor To Centralize Business Logic Processing | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis illustrates one way to implement a use case that requires a comparison between the current row status and the data returned by another query (no master-detail relationship). Thought for the Day "The danger from computers is not that they will eventually get as smart as men, but that we will meanwhile agree to meet them halfway." — Bernard Avishai Source: SoftwareQuotes.com

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  • Upgrade Ubuntu 11.10 to 12.10

    - by Daniel Minassian
    To whoever can help, I want to update the ubuntu on my laptop to 12.10 from the current version 11.10, when i click on the update manager i get a partial update gui, if i click cancel on that i get the gui for update which has three buttons check, install updates and upgrade. The upgrade button upgrades only to 12.04.1.LTS, when i press check it checks and gives me this error "W:Failed to fetch h t t p://lb.archive.ubuntu.com/ubuntu/dists/precise/main/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/lb.archive.ubuntu.com_ubuntu_dists_precise_main_i18n_Index , W:Failed to fetch h t t p://lb.archive.ubuntu.com/ubuntu/dists/precise/multiverse/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/lb.archive.ubuntu.com_ubuntu_dists_precise_multiverse_i18n_Index , W:Failed to fetch http://lb.archive.ubuntu.com/ubuntu/dists/precise/restricted/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/lb.archive.ubuntu.com_ubuntu_dists_precise_restricted_i18n_Index , W:Failed to fetch http://lb.archive.ubuntu.com/ubuntu/dists/precise/universe/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/lb.archive.ubuntu.com_ubuntu_dists_precise_universe_i18n_Index , E:Some index files failed to download. They have been ignored, or old ones used instead." Thank you for your time and help, Daniel Minassian

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  • Finding duplicate files?

    - by ub3rst4r
    I am going to be developing a program that detects duplicate files and I was wondering what the best/fastest method would be to do this? I am more interested in what the best hash algorithm would be to do this? For example, I was thinking of having it get the hash of each files contents and then group the hashes that are the same. Also, should there be a limit set for what the maximum file size can be or is there a hash that is suitable for large files?

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  • How to create hash or yml from top level attributes values of node?

    - by Sarah Haskins
    I have a chef recipe where I want to take all of the attributes under node['cfn']['environment'] and write them to a yml file. I could do something like this (it works fine): content = { "environment_class" => node['cfn']['environment']['environment_class'], "node_id" => node['cfn']['environment']['node_id'], "reporting_prefix" => node['cfn']['environment']['reporting_prefix'], "cfn_signal_url" => node['cfn']['environment']['signal_url'] } yml_string = YAML::dump(content) file "/etc/configuration/environment/platform.yml" do mode 0644 action :create content "#{yml_string}" end But I don't like that I have to explicitly list out the names of the attributes. If later I add a new attributes it would be nice if it automatically was included in the written out yml file. So I tried something like this: yml_string = node['cfn']['environment'].to_yaml But because the node is actually a Mash, I get a platform.yml file like this (it contains a lot of unexpected nesting that I don't want): --- !ruby/object:Chef::Node::Attribute normal: tags: [] cfn: environment: &25793640 reporting_prefix: Platform2 signal_url: https://cloudformation-waitcondition-us-east-1.s3.amazonaws.com/... environment_class: Dev node_id: i-908adf9 ... But what I want is this: ---- reporting_prefix: Platform2 signal_url: https://cloudformation-waitcondition-us-east-1.s3.amazonaws.com/... environment_class: Dev node_id: i-908adf9 How can I achieve the desired yml output w/o explicitly listing the attributes by name?

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  • I'm think n+1 in a hyper-v r2 cluster managed by scvmm is not a great idea anymore

    - by tony roth
    Around here the clusters (not hyper-v clusters) are typically configured as n+1, so they are asking me to create a n+1 hyper-v r2 clusters. These will configured with both csv's and live migration and managed via scvmm r2. My thinking is that its a waste in having a node sitting there idle. In my opinion it would be better to have headroom left over for what would traditionally the +1 server spread amongst the N nodes. Anybody have an opinion on this. thanks

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  • I'm thinking n+1 in a hyper-v r2 cluster managed by scvmm is not a great idea anymore

    - by tony roth
    Around here the clusters (not hyper-v clusters) are typically configured as n+1, so they are asking me to create a n+1 hyper-v r2 clusters. These will configured with both csv's and live migration and managed via scvmm r2. My thinking is that its a waste in having a node sitting there idle. In my opinion it would be better to have headroom left over for what would traditionally the +1 server spread amongst the N nodes. Anybody have an opinion on this. thanks

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  • What are best monitoring tool customizable for cluster / distributed system?

    - by Adil
    I am working on a system having multiple servers. I am interested in monitoring some server specific data like CPU/memory usage, disk/filesystem usage, network traffic, system load etc. and some other my process specific data. What are available open source that can serve my purpose? If it provides to customize the parameter to be monitored and monitor your own data by creating plugin / agent. Any suggestions? I heard of Nagios, Zabbix and Pandora but not sure if they provide such interface.

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  • Laptop Display Not Working

    - by etrask
    Hello, I just purchased this laptop. It is working fine but I want to use Xubuntu on it. I managed to get 10.04 installed and running but it did not recognize/use the wireless card. So I want to try 10.10. However, every time I try, the screen goes black and never comes back on. I have tried the Live CD and Alternate install CDs, for both Ubuntu and Xubuntu 10.10. After I select "Install Ubuntu" or "Try Ubuntu", the screen blacks out and never displays anything. So I deleted "quiet" and "splash" off the command line to see what messages would come up. A bunch of text flies by but it ends at: [time] TCP established hash table entries: 524288 (order: 11, 8388608 bytes) [time] TCP bind hash table entries 65536 (order: 8, 1048576 bytes) [time] TCP: Hash tables configured (established 524288 bind 65536) [time] TCP reno registered [time] UDP hash table entries: 2048 (order: 4, 65536 bytes) [time] UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes) [time] NET: Registered protocol family 1 And freezes here forever. I have tried nomodeset, vga=771, and xforcevesa with no progress. Is my video card simply not going to work with this distro? It seems strange that 10.04 would work fine but not 10.10. Any help is appreciated, thank you.

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  • eSTEP TechCast - December 2012

    - by uwes
    Dear partner, we are pleased to announce our next eSTEP TechCast on Thursday 6th of December and would be happy if you could join. Please see below the details for the next TechCast.Date and time:Thursday, 06. December 2012, 11:00 - 12:00 GMT (12:00 - 13:00 CET; 15:00 - 16:00 GST) Title: Innovations with Oracle Solaris Cluster 4 Abstract:Oracle Solaris Cluster 4.0 is the version of Solaris Cluster that runs with Oracle Solaris 11. In this webcast we will focus at the integration of the cluster software with the IPS packaging system of Solaris 11, which makes installing and updating the software much easier and much more reliable, especially with virtualization technologies involved. Our webcast will also reflect new versions of Oracle Solaris Cluster if they will be announced in the meantime. Target audience: Tech Presales Speaker: Hartmut Streppel Call Info:Call-in-toll-free number: 08006948154 (United Kingdom)Call-in-toll-free number: +44-2081181001 (United Kingdom) Show global numbers Conference Code: 803 594 3Security Passcode: 9876Webex Info (Oracle Web Conference) Meeting Number: 255 760 510Meeting Password: tech2011 Playback / Recording / Archive: The webcasts will be recorded and will be available shortly after the event in the eSTEP portal under the Events tab, where you could find also material from already delivered eSTEP TechCasts. Use your email-adress and PIN: eSTEP_2011 to get access. Feel free to have a look. We are happy to get your comments and feedback. Thanks and best regards, Partner HW Enablement EMEA

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  • Does LINQ require significantly more processing cycles and memory than lower-level data iteration techniques?

    - by Matthew Patrick Cashatt
    Background I am recently in the process of enduring grueling tech interviews for positions that use the .NET stack, some of which include silly questions like this one, and some questions that are more valid. I recently came across an issue that may be valid but I want to check with the community here to be sure. When asked by an interviewer how I would count the frequency of words in a text document and rank the results, I answered that I would Use a stream object put the text file in memory as a string. Split the string into an array on spaces while ignoring punctuation. Use LINQ against the array to .GroupBy() and .Count(), then OrderBy() said count. I got this answer wrong for two reasons: Streaming an entire text file into memory could be disasterous. What if it was an entire encyclopedia? Instead I should stream one block at a time and begin building a hash table. LINQ is too expensive and requires too many processing cycles. I should have built a hash table instead and, for each iteration, only added a word to the hash table if it didn't otherwise exist and then increment it's count. The first reason seems, well, reasonable. But the second gives me more pause. I thought that one of the selling points of LINQ is that it simply abstracts away lower-level operations like hash tables but that, under the veil, it is still the same implementation. Question Aside from a few additional processing cycles to call any abstracted methods, does LINQ require significantly more processing cycles to accomplish a given data iteration task than a lower-level task (such as building a hash table) would?

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  • Impact of Server Failure on Coherence Request Processing

    - by jpurdy
    Requests against a given cache server may be temporarily blocked for several seconds following the failure of other cluster members. This may cause issues for applications that can not tolerate multi-second response times even during failover processing (ignoring for the moment that in practice there are a variety of issues that make such absolute guarantees challenging even when there are no server failures). In general, Coherence is designed around the principle that failures in one member should not affect the rest of the cluster if at all possible. However, it's obvious that if that failed member was managing a piece of state that another member depends on, the second member will need to wait until a new member assumes responsibility for managing that state. This transfer of responsibility is (as of Coherence 3.7) performed by the primary service thread for each cache service. The finest possible granularity for transferring responsibility is a single partition. So the question becomes how to minimize the time spent processing each partition. Here are some optimizations that may reduce this period: Reduce the size of each partition (by increasing the partition count) Increase the number of JVMs across the cluster (increasing the total number of primary service threads) Increase the number of CPUs across the cluster (making sure that each JVM has a CPU core when needed) Re-evaluate the set of configured indexes (as these will need to be rebuilt when a partition moves) Make sure that the backing map is as fast as possible (in most cases this means running on-heap) Make sure that the cluster is running on hardware with fast CPU cores (since the partition processing is single-threaded) As always, proper testing is required to make sure that configuration changes have the desired effect (and also to quantify that effect).

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  • How failover should work in IIS cluster with Application Request Routing?

    - by username
    I have set up several servers with IIS and connected them to the load balancer - server with installed IIS Application Request Routing. I have created a server farm and added two servers. Then I stopped IIS on the first server and tried to open my web site. It returned me an error: 502 - Web server received an invalid response while acting as a gateway or proxy server. But if instead of stopping IIS I shut down the first server, I'm getting a response from the next server which is online. The question is, what the expected behaviour should be for failover with ARR, should it switch me to the next server if IIS is stopped and server is online?

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  • Why aren't the :locals hash variables being passed in to a partial, when called from inside my rake

    - by marshally
    I need to render a bunch of painfully long running partials using a rake task. When I try to pull the partial from a rake task, I get the dreaded "Called id for nil, which would mistakenly be 4" error, which usually means that my locals hash has not been properly set into the partial. Here's the rake task (some variable names have been changed to protect the innocent): namespace :precache do desc "Precache stuff" task :precache => :environment do av = ActionView::Base.new(Rails::Configuration.new.view_path, {}) av.class_eval do include ApplicationHelper end @user = User.find(21) @rank = Rank.find(2) data = av.render(:partial => "reports/listing", :locals => {:user => @user, :rank => @rank}) end end And this is the error that I am getting: ** Execute precache:precache rake aborted! Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id On line #1 of app/views/reports/listing.html.erb 1: <%- @rid = @rank.id %> 2: <%- @cid = @user.id %> 3: <%- cache(:action => 'reports', :key => [arg1, arg2, arg3] ) do %> 4: <%- app/views/reports/_downline_js.html.erb:1 lib/tasks/precache_fragments.rake:12 rake (0.8.7) lib/rake.rb:636:in `call' rake (0.8.7) lib/rake.rb:636:in `execute' rake (0.8.7) lib/rake.rb:631:in `each' rake (0.8.7) lib/rake.rb:631:in `execute' rake (0.8.7) lib/rake.rb:597:in `invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' rake (0.8.7) lib/rake.rb:590:in `invoke_with_call_chain' rake (0.8.7) lib/rake.rb:583:in `invoke' rake (0.8.7) lib/rake.rb:2051:in `invoke_task' rake (0.8.7) lib/rake.rb:2029:in `top_level' rake (0.8.7) lib/rake.rb:2029:in `each' rake (0.8.7) lib/rake.rb:2029:in `top_level' rake (0.8.7) lib/rake.rb:2068:in `standard_exception_handling' rake (0.8.7) lib/rake.rb:2023:in `top_level' rake (0.8.7) lib/rake.rb:2001:in `run' rake (0.8.7) lib/rake.rb:2068:in `standard_exception_handling' rake (0.8.7) lib/rake.rb:1998:in `run' rake (0.8.7) bin/rake:31 /usr/bin/rake:19:in `load' /usr/bin/rake:19 details: I'm using Rails 2.3.5 and Ruby 1.8.7. Developing on Mac OSX. Eventually I will be deploying to Heroku.

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  • Sharing large objects between ruby processes without a performance hit

    - by Gdeglin
    I have a Ruby hash that reaches approximately 10 megabytes if written to a file using Marshal.dump. After gzip compression it is approximately 500 kilobytes. Iterating through and altering this hash is very fast in ruby (fractions of a millisecond). Even copying it is extremely fast. The problem is that I need to share the data in this hash between Ruby on Rails processes. In order to do this using the Rails cache (file_store or memcached) I need to Marshal.dump the file first, however this incurs a 1000 millisecond delay when serializing the file and a 400 millisecond delay when serializing it. Ideally I would want to be able to save and load this hash from each process in under 100 milliseconds. One idea is to spawn a new Ruby process to hold this hash that provides an API to the other processes to modify or process the data within it, but I want to avoid doing this unless I'm certain that there are no other ways to share this object quickly. Is there a way I can more directly share this hash between processes without needing to serialize or deserialize it? Here is the code I'm using to generate a hash similar to the one I'm working with: @a = [] 0.upto(500) do |r| @a[r] = [] 0.upto(10_000) do |c| if rand(10) == 0 @a[r][c] = 1 # 10% chance of being 1 else @a[r][c] = 0 end end end @c = Marshal.dump(@a) # 1000 milliseconds Marshal.load(@c) # 400 milliseconds

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  • Using an SHA1 with Microsoft CAPI

    - by Erik Jõgi
    I have an SHA1 hash and I need to sign it. The CryptSignHash() method requires a HCRYPTHASH handle for signing. I create it and as I have the actual hash value already then set it: CryptCreateHash(cryptoProvider, CALG_SHA1, 0, 0, &hash); CryptSetHashParam(hash, HP_HASHVAL, hashBytes, 0); The hashBytes is an array of 20 bytes. However the problem is that the signature produced from this HCRYPTHASH handle is incorrect. I traced the problem down to the fact that CAPI actually doesn't use all 20 bytes from my hashBytes array. For some reason it thinks that SHA1 is only 4 bytes. To verify this I wrote this small program: HCRYPTPROV cryptoProvider; CryptAcquireContext(&cryptoProvider, NULL, NULL, PROV_RSA_FULL, 0); HCRYPTHASH hash; HCRYPTKEY keyForHash; CryptCreateHash(cryptoProvider, CALG_SHA1, keyForHash, 0, &hash); DWORD hashLength; CryptGetHashParam(hash, HP_HASHSIZE, NULL, &hashLength, 0); printf("hashLength: %d\n", hashLength); And this prints out hashLength: 4 ! Can anyone explain what I am doing wrong or why Microsoft CAPI thinks that SHA1 is 4 bytes (32 bits) instead of 20 bytes (160 bits).

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  • Am I going the right way to make login system secure with this simple password salting?

    - by LoVeSmItH
    I have two fields in login table password salt And I have this little function to generate salt function random_salt($h_algo="sha512"){ $salt1=uniqid(rand(),TRUE); $salt2=date("YmdHis").microtime(true); if(function_exists('dechex')){ $salt2=dechex($salt2); } $salt3=$_SERVER['REMOTE_ADDR']; $salt=$salt1.$salt2.$salt3; if(function_exists('hash')){ $hash=(in_array($h_algo,hash_algos()))?$h_algo:"sha512"; $randomsalt=hash($hash,md5($salt)); //returns 128 character long hash if sha512 algorithm is used. }else{ $randomsalt=sha1(md5($salt)); //returns 40 characters long hash } return $randomsalt; } Now to create user password I have following $userinput=$_POST["password"] //don't bother about escaping, i have done it in my real project. $static_salt="THIS-3434-95456-IS-RANDOM-27883478274-SALT"; //some static hard to predict secret salt. $salt=random_salt(); //generates 128 character long hash. $password =sha1($salt.$userinput.$static_salt); $salt is saved in salt field of database and $password is saved in password field. My problem, In function random_salt(), I m having this FEELING that I'm just making things complicated while this may not generate secure salt as it should. Can someone throw me a light whether I m going in a right direction? P.S. I do have an idea about crypt functions and like such. Just want to know is my code okay? Thanks.

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  • Using an SHA1 with Micrsoft CAPI

    - by Erik Jõgi
    Hello, I have an SHA1 hash and I need to sign it. The CryptSignHash() method requires a HCRYPTHASH handle for signing. I create it and as I have the actual hash value already then set it: CryptCreateHash(cryptoProvider, CALG_SHA1, 0, 0, &hash); CryptSetHashParam(hash, HP_HASHVAL, hashBytes, 0); The hashBytes is an array of 20 bytes. However the problem is that the signature produced from this HCRYPTHASH handle is incorrect. I traced the problem down to the fact that CAPI actually doesn't use all 20 bytes from my hashBytes array. For some reason it thinks that SHA1 is only 4 bytes. To verify this I wrote this small program: HCRYPTPROV cryptoProvider; CryptAcquireContext(&cryptoProvider, NULL, NULL, PROV_RSA_FULL, 0); HCRYPTHASH hash; HCRYPTKEY keyForHash; CryptCreateHash(cryptoProvider, CALG_SHA1, keyForHash, 0, &hash); DWORD hashLength; CryptGetHashParam(hash, HP_HASHSIZE, NULL, &hashLength, 0); printf("hashLength: %d\n", hashLength); And this prints out hashLength: 4 ! Can anyone explain what I am doing wrong or why Microsoft CAPI thinks that SHA1 is 4 bytes (32 bits) instead of 20 bytes (160 bits). Thank you.

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  • Why might a System.String object not cache its hash code?

    - by Dan Tao
    A glance at the source code for string.GetHashCode using Reflector reveals the following (for mscorlib.dll version 4.0): public override unsafe int GetHashCode() { fixed (char* str = ((char*) this)) { char* chPtr = str; int num = 0x15051505; int num2 = num; int* numPtr = (int*) chPtr; for (int i = this.Length; i > 0; i -= 4) { num = (((num << 5) + num) + (num >> 0x1b)) ^ numPtr[0]; if (i <= 2) { break; } num2 = (((num2 << 5) + num2) + (num2 >> 0x1b)) ^ numPtr[1]; numPtr += 2; } return (num + (num2 * 0x5d588b65)); } } Now, I realize that the implementation of GetHashCode is not specified and is implementation-dependent, so the question "is GetHashCode implemented in the form of X or Y?" is not really answerable. I'm just curious about a few things: If Reflector has disassembled the DLL correctly and this is the implementation of GetHashCode (in my environment), am I correct in interpreting this code to indicate that a string object, based on this particular implementation, would not cache its hash code? Assuming the answer is yes, why would this be? It seems to me that the memory cost would be minimal (one more 32-bit integer, a drop in the pond compared to the size of the string itself) whereas the savings would be significant, especially in cases where, e.g., strings are used as keys in a hashtable-based collection like a Dictionary<string, [...]>. And since the string class is immutable, it isn't like the value returned by GetHashCode will ever even change. What could I be missing? UPDATE: In response to Andras Zoltan's closing remark: There's also the point made in Tim's answer(+1 there). If he's right, and I think he is, then there's no guarantee that a string is actually immutable after construction, therefore to cache the result would be wrong. Whoa, whoa there! This is an interesting point to make (and yes it's very true), but I really doubt that this was taken into consideration in the implementation of GetHashCode. The statement "therefore to cache the result would be wrong" implies to me that the framework's attitude regarding strings is "Well, they're supposed to be immutable, but really if developers want to get sneaky they're mutable so we'll treat them as such." This is definitely not how the framework views strings. It fully relies on their immutability in so many ways (interning of string literals, assignment of all zero-length strings to string.Empty, etc.) that, basically, if you mutate a string, you're writing code whose behavior is entirely undefined and unpredictable. I guess my point is that for the author(s) of this implementation to worry, "What if this string instance is modified between calls, even though the class as it is publicly exposed is immutable?" would be like for someone planning a casual outdoor BBQ to think to him-/herself, "What if someone brings an atomic bomb to the party?" Look, if someone brings an atom bomb, party's over.

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