Fundamentals of Encryption Technologies

What this chapter covers

Fundamentals of Encryption Technologies is 10% of the Huawei HCIA-Security H12-711 exam. It covers how encryption developed from classical ciphers to public key cryptography, the basic terms and the difference between symmetric and asymmetric encryption, the common algorithms (DES, 3DES, AES, SM4, RSA, DH, ECC, SM2) and hash algorithms such as MD5, SHA-1, SHA-2 and SM3.

Questions are single-answer, multiple-answer without a stated count, true/false, drag and drop and typed fill-in-the-blank, often "Which of the following statements is true?". Some show firewall topology figures or display output, but most questions in this chapter test algorithm facts: key lengths, block sizes, digest lengths and which algorithm is symmetric, asymmetric or a hash.

It has 4 outline topics, and two pages cover them.

How the topics fit together

The history explains why each new idea appeared, and the fundamentals give you the terms. The algorithm families then fill those terms with real names and numbers, and hash algorithms add integrity on top of confidentiality.

Everything here is reused in the next two chapters. The digital envelope, digital signature and certificate in the PKI chapter, and IPsec and SSL VPN in the applications chapter, are built only from these pieces.

How to use these pages

Each topic page has the same shape, so you can skim for what you need.

• What it is: the idea in plain words.
• How it works: the mechanism, with tables and examples.
• What to remember for the exam: the facts to memorize.
• Common mistakes: the classic traps.
• Check yourself: three questions to test your understanding.

Read each configuration snippet and say what it does before reading the explanation. The exam often shows a short configuration and asks which traffic is permitted, translated or allowed to log in.