Cryptography and identity Authentication Technology-- principles and practical applications of PKI & lt;3>

Implement encryption protection for office build application

Word as an example:

a. The default word uses the rc4 encryption algorithm.

b. Understand the risk of the password.

1. Set the office password.

two。 Crack the office password. Use Accent Office Password Recovery.

3. Process:

a. Install softwar

b. Startup software

c. Open the cracked file and click start.

d. Pop-up prompt: whether your password has some identifying characters.

e. Character set, next step

f. Tip: whether you remember part of the password.

g. The range of passwords used, check.

h. The length of the password, start search character, next

i. Sets the parameter display.

4. The time to crack the file is related to the strength of the password.

Deploy EFS encrypted file system and recovery agent

1.EFS fundamentals:

Is a hybrid encryption system used on the NTFS encryption system.

Transparent when encrypted.

How it works: the driver of 1.EFS calls Microsoft encryption Service provider MCP to generate a file encryption key FEK

2.EFS uses FEK to encrypt the file. Note that only the data of the file is encrypted, and other attributes are weighted.

The limit remains the same. 3.EFS stores the encrypted files on NTFS. 4.EFS calls "MCP" again in order to obtain the public of EFS

Key. Encrypt file system Note: encrypt another copy of FEK with public key at the same time, and the password can be recovered. Reduced security

But you can recover the document and reduce the possibility of document loss

two。 Encrypt the file system for encryption, and the recovery agent:

1. Set up three users on the computer.

2. Create a document and encrypt it, NTFS partition.

The private key of 3.user1, on the certificate. MMc, export the private key

4.user2 decrypted the document unsuccessfully because there was no private key.

5.user2 to the private key of the incoming user1. Check successfully.

The characteristics of hybrid encrypted file system.

3. The recovery agent should be started before the file is encrypted.

-- "gpedit.msc-- > public key policy"-- "restore agent--" cmd-- "cipher.exe/r:dra generates the certificate of the recovery agent.

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-- Group Policy-- encrypted File system recovery Agent-- add Certificate-- recovery Agent Import computer

-- "Certificate Import computer