Android system requires that every Android application must be digitally signed before it can be installed in the system. That is to say, if an Android application is not digitally signed, there is no way to install it in the system!
Android uses digital signatures to identify the author of an application and establish a trust relationship between applications, rather than deciding which applications the end user can install.
The digital signature is completed by the author of the application program and does not need the authentication of an authoritative digital certificate signing authority. It is only used to make the application package self-verify.
Usually, our program can be installed and executed on the simulator, because in the process of application development, ADT is compiled in Debug interview, so it will automatically sign with the default key and certificate, while when compiled in release mode, apk file will not be automatically signed, so it needs to be signed manually. Signing apk can bring the following benefits: 1. Application upgrade: If you want users to seamlessly upgrade to the new version, you must sign with the same certificate. This is because if the upgraded application is signed with the same certificate, only the upgraded application will be allowed to be installed. If you use a different certificate, your application will be required to use a different package name, which is equivalent to installing a brand new application. If you want to upgrade the application, the signing certificate should be the same and the package name should be the same! 2. Modularization of applications: Android system can allow multiple applications signed by the same certificate to be executed in one program, and the system actually treats them as a single application. At this point, our application can be deployed in a modular way, and users can upgrade one of module 3, code or data independently. Android provides a signature-based permission mechanism, so one application can be exposed to another application signed by the same certificate. Using the same certificate to sign multiple applications, and using the permission check based on the signature, the code and data between applications can be safely shared. If different applications want to enjoy data or code, they should be executed in the same program and signed with the same certificate.
What is the function of word electronic signature? The reason for digitally signing a document is similar to the reason for signing a paper document. Digital signature is verified by computer encryption (authentication: the process of verifying whether the identity declared by personnel and products is true. For example, the code source and integrity of a software publisher can be confirmed by verifying the digital signature used to sign the code. ) digital information, such as documents, emails and macros. Digital signatures help ensure that:
Trusted digital signature helps to ensure that the signer's identity is consistent with the announcement.
Integrity digital signature helps to ensure that the content will not be changed or tampered with after being digitally signed.
Undeniably, digital signature is helpful to prove the validity of the signed content to all parties. "Deny" means that the signer denies any behavior related to the content of the signature.
In order to ensure the above content, the content creator must digitally sign the content with a signature that meets the following conditions:
The digital signature is valid (valid: certificate status. After checking the certificate according to the database of the certification authority, it is found that it is legal and up-to-date, and has not expired or been revoked. A file signed by a valid certificate and unchanged after signing is considered as a valid file. )。
Certificates associated with digital signatures (certificates: digital methods to prove identity and authenticity. Certificates are issued by certification authorities, and like driver's licenses, they may expire or be revoked. ) valid (not expired).
The signer or company as the publisher is trustworthy (trust: indicates whether you trust the receiver (individual or group) who issued the certificate. The default setting is "Inherit the trust relationship of the issuer", that is, the certificate is trusted because the issuer (usually the certificate authority) is trusted. )。
Certificates associated with digital signatures are issued by an authoritative certificate authority (CA) (CA: a business organization that issues digital certificates, tracks certificate issuers, signs certificates to verify their validity, and tracks certificates that have been revoked or expired. ) to the signature publisher.
What is the function of credit card signature? It is equivalent to having a contract dispute and having a basis. Usually, it's nothing.
What is the function of mobile phone software signature? At present, powerful companies or companies that really need it will buy Nokia's high-level rights.
Limited certificates, usually security vendors. We don't need to sign the software of such companies, and there are many more.
Software is a general application software, which has nothing to do with the system. They have low permission and cannot be saved.
In danger, such as internet TV software, reading software, QQ, theme, etc. You don't need to sign. You need to sign.
The name of the software can be roughly divided into the following situations: (1) boot, such as incoming calls.
Pass, A4 self-signed version; (2) Don't let you operate things that can be automatically executed, such as screensavers; (3) Input
If the system folder is modified, for example, most software is in the late stage of localization, reinstall the localization patch.
Need to sign when necessary.
What is the function of a reliable electronic signature? According to Article 14 of People's Republic of China (PRC) Electronic Signature Law: "A reliable electronic signature has the same legal effect as a handwritten signature or seal." It can be seen that only by using "reliable electronic signature" can electronic contracts have the same legal effect as paper contracts, that is, documentary evidence effect.
What is the function of C# project file signature? Mainly to prevent tampering and cracking. For example, the program you write includes 1 exe and several dlls. EXES took a lot of effort, and it has your company's logo on it. Now a hacker decompiles a dll and finds that it is easy to modify a dll, such as a dll with a registration code, which leads to bypassing the verification code. Another hacker changed the good dll into the function of deleting all files on the disk, causing users to blacklist your company.
If you sign it, you can guarantee that exe can only call its own dll. If they tamper with your dll, exe will report an error and the dll cannot be found.
What is the purpose of the driver's signature? It can be confirmed that the driver is not compatible with Windows (but it does not mean that the driver without signature is not compatible with Windows).
Happy New Year!
What is the Android signature tool for? It's used to sign apk. But you must have a key, or you can use eclipse to generate one yourself. Signature plays an important role in preventing the program from being tampered with after it is released. Usually, the private key is used for signing. After signing with the private key, a harsh sequence of values will be generated. When the public key is verified (on the mobile phone), a harsh sequence will be generated again according to the contents of the file. If it is the same as the harsh sequence in apk, it means that apk has not been tampered with after its release.
There is no harm in forbidding drivers to forcibly sign.
Driver signature, also known as driver digital signature, is completed by Microsoft's Windows Hardware Equipment Quality Laboratory. Hardware developers will hand over their hardware devices and corresponding drivers to the laboratory, which will test them. After passing the test, the laboratory will add digital signatures to their drivers. Because the digital signature is made by Microsoft.
Benefits of using digital signature drivers:
Security Because the digital signature is aimed at all the software of the whole driver, any change to the driver after the signature is completed will invalidate the signature, thus avoiding the possibility of adding malicious programs such as malicious codes and spreading viruses to the driver.