假设我们有一个流密码 CSPRNG,其中 Key 是密钥,可以使用如下步骤来构造哈希函数 \text{HF is a HashFunction with StreamCipher}: 为了构造哈希函数使用两个流密码(Stream Cipher),我们采用了一种复合构造方法,利用安全伪随机数生成器(CSPRNG)、不可逆函数和混合状态(MixState)功能来确保哈希函数的抗碰撞性和不可逆...
在不使用传统对称密码学结构的情况下,我们可以通过伪随机函数(PRF)和洗牌算法来构建伪随机置换(PRP)。这里,我们将探讨两种实现方式:一种是依赖密钥的洗牌和反洗牌算法,另一种是不依赖密钥的洗牌和反洗牌算法。以下是具体步骤和证明。 依赖密钥的洗牌和反洗牌算法 依赖密钥的Fisher-Yates洗牌算法 生成伪随机数列: 使...
序列密码(Stream Cipher):又称流密码,将明文消息按字符逐位进行加密。分组密码(Block Cipher):在分组密码中将明文消息分组(每组有多个字符),逐组进行加密。 1. **问题判断**:题目未包含完整答案(存在“xx”占位符),但结构完整,无矛盾或缺失关键信息,因此需补充完整。2. **序列密码核心**:根据密码学定义,序列...
KeyBlock CipherStream Cipher Definition Block Cipher is the type of encryption where the conversion of plaintext is performed by taking its block at a time. Stream Cipher is the type of encryption where the conversion of plaintext is performed by taking one byte of the plaintext at a time. ...
Hence, the ciphertext for this particular example will be 10001000. We can regenerate the original plaintext by performing an XOR operation between ciphertext and keystream. 4. Block Cipher Like a stream cipher, a block cipher encrypts a block of given plaintext using a key and a ...
Clearly, while Top Secret information or matters of national security may warrant the use of a one-time pad, such a cipher would just be too impractical for day-to-day public use. The key of a stream cipher is no longer as long as the original message. Hence, it can no longer guarant...
Block Cipher Modes of Operation and Stream Ciphers CSE 651: Introduction to Network Security Abstract • We will discuss –How to use block ciphers? –RC4: a widely used stream cipher –Problems with WEP’s use of RC4 2 Modes of Operations How to use a block cipher?
RC4:awidelyusedstreamcipher ProblemswithWEP’suseofRC4 * ModesofOperations Howtouseablockcipher? Blockciphersencryptfixed-sizeblocks e.g.DESencrypts64-bitblocks Weneedsomewaytoencryptamessageofarbitrarylength e.g.amessageof1000bytes NISTdefinesseveralwaystodoit ...
Title: Encryption technique using stream cipher and block cipher United States Patent 6415032 Abstract: A method is provided for generating a pseudo-random sequence of integers, and the method is applied to the encryption of messages. The method uses a key K and a pair of prime numbers p and...
A dual use block/stream cipher is provided with a first key section and a data section. The first key section is to be initialized with a first cipher key, and to successively trans