added tpm

windows/device-security/tpm/how-windows-uses-the-tpm.md

@@ -45,7 +45,7 @@ The security features of Windows 10 combined with the benefits of a TPM offer pr
 
 ## Platform Crypto Provider
 
-Historically, Windows includes a cryptography framework called *Cryptographic API: Next Generation* (CNG), the basic approach of which is to implement cryptographic algorithms in different ways but with a common application programming interface (API). Applications that use cryptography can use the common API without knowing the details of how an algorithm is implemented much less the algorithm itself.
+Windows includes a cryptography framework called *Cryptographic API: Next Generation* (CNG), the basic approach of which is to implement cryptographic algorithms in different ways but with a common application programming interface (API). Applications that use cryptography can use the common API without knowing the details of how an algorithm is implemented much less the algorithm itself.
 
 Although CNG sounds like a mundane starting point, it illustrates some of the advantages that a TPM provides. Underneath the CNG interface, Windows or third parties supply a cryptographic provider (that is, an implementation of an algorithm) implemented as software libraries alone or in a combination of software and available system hardware or third-party hardware. If implemented through hardware, the cryptographic provider communicates with the hardware behind the software interface of CNG.
 
@@ -132,7 +132,7 @@ Mobile device management (MDM) solutions can receive simple security assertions
 
 ## Credential Guard
 
-Credential Guard is a new feature in Windows 10 that helps protect Windows credentials in organizations that have deployed AD DS. Historically, a user’s credentials (e.g., logon password) was hashed to generate an authorization token. The user employed the token to access resources that he or she was permitted to use. One weakness of the token model is that malware that had access to the operating system kernel could look through the computer’s memory and harvest all the access tokens currently in use. The attacker could then use harvested tokens to log on to other machines and collect more credentials. This kind of attack is called a “pass the hash” attack, a malware technique that infects one machine to infect many machines across an organization.
+Credential Guard is a new feature in Windows 10 that helps protect Windows credentials in organizations that have deployed AD DS. Historically, a user’s credentials (e.g., logon password) were hashed to generate an authorization token. The user employed the token to access resources that he or she was permitted to use. One weakness of the token model is that malware that had access to the operating system kernel could look through the computer’s memory and harvest all the access tokens currently in use. The attacker could then use harvested tokens to log on to other machines and collect more credentials. This kind of attack is called a “pass the hash” attack, a malware technique that infects one machine to infect many machines across an organization.
 
 Similar to the way Microsoft Hyper-V keeps virtual machines (VMs) separate from one another, Credential Guard uses virtualization to isolate the process that hashes credentials in a memory area that the operating system kernel cannot access. This isolated memory area is initialized and protected during the boot process so that components in the larger operating system environment cannot tamper with it. Credential Guard uses the TPM to protect its keys with TPM measurements, so they are accessible only during the boot process step when the separate region is initialized; they are not available for the normal operating system kernel. The local security authority code in the Windows kernel interacts with the isolated memory area by passing in credentials and receiving single-use authorization tokens in return.