password appears in pairs, one for the private key (secret key) and one for the public keyOne-way encryption, hash encryption: Extracting data signatures, often used for data integrity checks1. Avalanche effect2, fixed-length outputMd5:message Digest, 128-bit fixed-length outputSha1:secure Hash algorithm, 160-bit fixed-length outputUser management:Useradd,userdel,usermod,passwd,chsh,chfn,finger,chageGroup Management:groupadd,groupdel,groupmod,gpasswd
, hash encryption: Extracting data signatures, often used for data integrity checks1, non-reversible2, Avalanche effect: Small changes in input data, will cause a huge change in the data signature-anti-brute force3, fixed-length outputCommon one-way encryption is:Md5:message Digest, (Information Digest, 5 is the version number), MD5 is a 128-bit fixed-length output,Sha1:secure hash algorithm, (Secure hashing algorithm), 160-bit fixed-length outputExam
In the spring cloud distribution, a fuse is a circuit breaker, which is actually a meaning.Why use a fuse?In the distributed, we split the project into multiple service units according to the business or function, and each service unit relies on and invokes the function through service registration and subscription, and as the project and business expands, the number of service units is increasing and the dependence of each other is becoming more and more complex. A service unit may have a probl
In a microservices architecture, the service is split into services according to the business, and the service and service can call each other (RPC), which can be invoked with Resttemplate+ribbon and feign in spring cloud. To ensure their high availability, a single service is typically deployed in a cluster. Due to network reasons or their own reasons, the service does not guarantee that 100% is available, if a single service problem, call the service will be a thread blocking, if there is a la
, so the general data encryption we often use symmetric encryption algorithm, although symmetric encryption algorithmCan resolve data confidentiality, but cannot manage key issuesData integrity: Ensures that the transmitted data is not compromisedFor data integrity, a one-way encryption algorithm is generally used, one-way encryption has the characteristics of:1, input, the output must be the same2, has the avalanche effect, is the small change may ca
Seven field explanations in the/etc/passwd directory
Account user name is also called login name
Password encrypted user name is typically x true user encrypted password under/etc/shadow file
ID of UID User
Group ID of the GID user
GECOS other information such as the user's full name, separated by commas
Home directory for user directory Users
Shell user's default shell
/etc/shells This directory for the current system legal shellExplanation of 9 fields in t
In a microservices architecture, the service is split into services based on the business, and services and services can be called each other (RPC), which can be invoked with the rest Template + ribbon and feign in spring cloud. To ensure their high availability, a single service is typically deployed in a cluster. Due to network reasons or their own reasons, the service does not guarantee that 100% is available, if a single service problem, call the service will be a thread blocking, if there i
I know this project is a lot of bugs, can't finish on time, even if the boss fired me should be. Once had a unit test opportunity put in front of me, I did not cherish, wait until later project avalanche to regret. If God can give me another chance, I will say to the boss: I want to do unit test! If you have to add a date to the unit test, I hope it will be.
...
I am not here to say how to do unit testing, since we can not specify how to write the p
Animation is the most influential and dominant in every year. Web developers use different experiments to achieve animation, from the simplest foundation effect to the groundbreaking presentation results. There is no doubt that this avalanche of animation has been considered the most advanced technology in the history of Web technology. has been developed to a new level by the Web developers who are never satisfied with the status quo. The animation i
informationThe password (/etc/passwd) attribute is detailed (left to right):1.account: Login Name2.password: Password (if display x placeholder proof password not shown in shadow)3.UID: User ID number4.GID: Basic Group ID5.comment: Note The user release information (some are empty)6.HOME dir: Home directory7.SHELL: User's default SHELLCat/etc/shell can see which shells are legitimateCat/etc/shadow View ShadowThe password (/etc/shadow) attribute is detailed (left to right):1.account: Login Name2
Root:x:0:0:root:/root:/bin/bashbin:x:1:1:bin:/bin:/sbin/nologindaemon:x:2:2:daemon:/sbin:/sbin/nologinadm:x : 3:4:adm:/var/adm:/sbin/nologinlp:x:4:7:lp:/var/spool/lpd:/sbin/nologinsync:x:5:0:sync:/sbin:/bin/syncPassword Complexity policy:
Numbers, lowercase, uppercase, and special characters at least three classes
Minimum Length 5 bits
Don't use easy-to-guess passwords
Revise regularly and do not use passwords that have been used recently
Encryp
attack DDoS
Flow rate up to dozens of G
Distributed (broiler, agent)
Very difficult to defend
Dos Attack defense
Firewall
Switch/router
Flow Cleaning
High Anti-IP
Avoid heavy logic business
Quick Fail Quick return
Anti-avalanche mechanism
Lossy services
Cdn
Replay attackThe request was intercepted or bugged, then exploited by the attacker and re-sentHarm
Users have been spen
**************************************************************************** is discarded directly. Exhibition Description: 01: The characteristics of different data (data fingerprint information) is not possible consistent single encryption algorithm features · Data input, signature information output must be the same · Avalanche effect, small change in input, will cause a huge change in output · Fixed-length output, regardless of the source data si
does not natively support a coordinated approach to multiple events, and requires a third-party library. Such as:var proxy = new Eventproxy ();The all method acts: After the event is listened to, the callback is executed and the received parameter is listened to the incoming callbackProxy.all (' profile ', ' timeline ', ' Skins ', function (profile, timeline, skin) {Todo});Api.getuser (' username ', function (profile) {Proxy.emit ("Profile", profile); Trigger the event profile and pass in the a
First, preface Nearly all Java-related interviews will ask the cache question, the basic question is what is the "28 law", What is "hot data and cold data", the more complex will ask the cache avalanche, cache penetration, cache warm-up, cache updates, cache degradation and other issues, these seemingly uncommon concepts, are related to our cache server, generally used cache server has Redis, memcached, etc., and the author is currently the most co
server, where the static resources of the site are cached, without the need to continue to forward the request to the application server, directly back to the user
Local cache. The hotspot data is cached locally on the application server, and the application can be accessed directly in local memory without having to access the data tier
Distributed cache. The data is stored in a dedicated distributed cache cluster, and the application server accesses the cached data over network traffic
First, the problem foundWith the CPU usage of the line machine, we can see that starting from April 8, with the increase of CPU usage in time, the end-use rate reaches 100%, which causes the online service to be unavailable, then recovers after restarting the machine.Second, troubleshooting ideasA simple analysis of the possible problems in the area, divided into 5 directions:1. System itself code problems2. Avalanche effect due to problems in the int
hash value is found in the database.Select a hashing algorithm
The cryptographic hash algorithm is a common hashing algorithm. Similar to md5,sha1,sha256 this can be found in any language can be called a standard library, they are very effective for simple use cases.
For example, to import a hashlib module in Python, and then call a function, you can generate a string or a hash value for a file.
>>> import hashlib
# Calculating the hash value of a string.
>>> hashlib.md5 (' The quic
First, what is Handlersocket?Handlersocket is a MySQL plugin written by Akira Higuchi. In the form of MySQL Daemon plugin to provide similar NoSQL network services, through this plug-in, you can directly with the MySQL back-end storage engine to do key-value interaction, eliminating the MySQL upper layer of SQL interpretation, open the closed table, Create a CPU overhead, such as a query plan.
Most of the Web sites currently using MySQL use Memcache as the key-value cache. Although such a struc
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