Objectives of Chapter 11: To define message integrity; to define message authentication; to define criteria for a cryptographic hash function; to define the Random Oracle Model and its role in evaluating the security of cryptographic hash functions; to distinguish between an MDC and a MAC; to discuss some common MACs.
Requirements - must be able to verify that:
1. Message came from apparent source or author,
2. Contents have not been altered,
3. Sometimes, it was sent at a certain time or sequence.
Protection against active attack (falsification of data and transactions)
Objectives of Chapter 14: To distinguish between message authentication and entity authentication; to define witnesses used for identification; to discuss some methods of entity authentication using a password; to introduce some challenge-response protocols for entity authentication; to introduce some zero-knowledge protocols for entity authentication; to define biometrics and distinguish between physiological and behavioral techniques.
Lecture 15: Hashing for message authentication. The goals of this chapter are: What is a hash function? Different ways to use hashing for message authentication, the one-way and collision-resistance properties of secure hash functions, the birthday paradox and the birthday attack, structure of cryptographically secure hash functions,...
Classified along three independent dimensions:
The type of operations used for transforming plaintext to ciphertext
The number of keys used
symmetric (single key)
asymmetric (two-keys, or public-key encryption)
The way in which the plaintext is processed
MD5 [MD5] is a message digest algorithm that takes as input a message
of arbitrary length and produces as output a 128-bit "fingerprint" or
"message digest" of the input. The published attacks against MD5
show that it is not prudent to use MD5 when collision resistance is
required. This document replaces the security considerations in RFC
[HMAC] defined a mechanism for message authentication using
cryptographic hash functions. Any message digest algorithm can be
used, but the cryptographic strength of HMAC depends on the
properties of the underlying hash function.
Enterprise Java Bean là các thành phần công nghệ phía máy chủ dùng để đóng gói lớp logic nghiệp vụ (business logic) và hổ trợ mạnh việc thực hiện các giao tác và bảo mật. Enterprise Java Bean cũng có một tích hợp một ngăn xếp cho messaging, scheduling, remote access, web service endpoints (SOAP and REST), dependency injection, component life cycle,..vv.
This chapter considers key establishment protocols and related cryptographic techniques
which provide shared secrets between two or more parties, typically for subsequent use
as symmetric keys for a variety of cryptographic purposes including encryption, message
authentication, and entity authentication. The main focus is two-party key establishment,
with the aid of a trusted third party in some cases.
Ubiquitous learning and foreign language learning in listening
Ubiquitous learning enables learners to learn in their daily life and helps them to
overcome limitations of time and space. Learners who study a foreign language with
mobile devices will be able to experience learning from an authentic situation and have
their learning performance enhanced (Nash, 2007), as multiple sense stimuli may be
more helpful to learners in absorbing knowledge. So far, ubiquitous learning has been
implemented in many types ...
Cryptographic hash functions play a fundamental role in modern cryptography. While related
to conventional hash functions commonly used in non-cryptographic computer applications
– in both cases, larger domains are mapped to smaller ranges – they differ in several
important aspects. Our focus is restricted to cryptographic hash functions (hereafter, simply
hash functions), and in particular to their use for data integrity and message authentication.
Hash Function, Message Digest and Message Authentication Code
Khi công nghệ chữ ký kỹ thuật số trở nên rộng rãi hơn hiểu và sử dụng, nhiều quốc gia trên toàn thế giới đang cạnh tranh phát triển các tiêu chuẩn chữ ký riêng của họ để sử dụng và các ứng dụng của họ. Một số ứng dụng điện tử sử dụng chữ ký số trong thương mại điện tử (thương mại điện tử) bao gồm e-mail và các giao dịch tài chính.
The remote access server duplicates the hash and compares it to the hash in
the MS-CHAP Response. If the hashes are the same, the remote access
server sends back an MS-CHAP Success message. If the hashes are
different, an MS-CHAP Failure message is sent.
Encryption is a widely used technique which involves
making information indecipherable to protect it from
unauthorised viewing or use, especially during
transmission or when it is held on removable magnetic
media. Encryption is usually based on a key(s)
without which the information cannot be decoded
(decrypted). The most widely used encryption system
is DES (Data Encryption Standard) although
increasingly this is being replaced commercially by
the more secure public key system RSA.
Presence of the network makes a distributed system susceptible to security attacks such as tampering of messages and masquerading, which can be launched through interprocess messages. This chapter discusses authentication and message security measures used in distributed operating systems to thwart such attacks. Methods of verifying authenticity of data are also discussed.