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HMAC
In cryptography, an HMAC (sometimes expanded as either keyed-hash message authentication code or hash-based message authentication code) is a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. As with any MAC, it may be used to simultaneously verify both the data integrity and authenticity of a message. HMAC can provide authentication using a shared secret instead of using digital signatures with asymmetric cryptography. It trades off the need for a complex public key infrastructure by delegating the key exchange to the communicating parties, who are responsible for establishing and using a trusted channel to agree on the key prior to communication. Details Any cryptographic hash function, such as SHA-2 or SHA-3, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMAC-X, where X is the hash function used (e.g. HMAC-SHA256 or HMAC-SHA3-512). The cryptographic strength of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible. The TLS protocol aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. It runs in the presentation layer and is itself composed of two layers: the TLS record and the TLS handshake protocols. The closely related Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications. In technical writing you often you will see references to (D)TLS when it applies to both versions. TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ran Canetti
Ran Canetti (Hebrew: רן קנטי) is a professor of Computer Science at Boston University. and the director of the Check Point Institute for Information Security and of the Center for Reliable Information System and Cyber Security. He is also associate editor of the Journal of Cryptology and Information and Computation. His main areas of research span cryptography and information security, with an emphasis on the design, analysis and use of cryptographic protocols. Biography Born in 1962 in Tel Aviv, Israel, Canetti obtained his BA in Computer Science in 1989, his BA in Physics in 1990, and his M.Sc in Computer Science in 1991, all from the Technion, Haifa. He received his PhD in 1995 from the Weizmann Institute, Rehovot under the supervision of Prof. Oded Goldreich. He then completed his post-doctoral training at the Lab of Computer Science, at the Massachusetts Institute of Technology (MIT) in 1996 under the supervision of Prof. Shafi Goldwasser. He then joined IBM� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPsec
In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs). IPsec includes protocols for establishing mutual authentication between agents at the beginning of a session and negotiation of cryptographic keys to use during the session. IPsec can protect data flows between a pair of hosts (''host-to-host''), between a pair of security gateways (''network-to-network''), or between a security gateway and a host (''network-to-host''). IPsec uses cryptographic security services to protect communications over Internet Protocol (IP) networks. It supports network-level peer authentication, data origin authentication, data integrity, data confidentiality ( encryption), and replay protection (protection from replay attacks). The initial IPv4 suite was developed with f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Authentication Code
In cryptography, a message authentication code (MAC), sometimes known as a ''tag'', is a short piece of information used for authenticating a message. In other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed. The MAC value protects a message's data integrity, as well as its authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the message content. Terminology The term message integrity code (MIC) is frequently substituted for the term ''MAC'', especially in communications to distinguish it from the use of the latter as '' media access control address'' (''MAC address''). However, some authors use MIC to refer to a message digest, which aims only to uniquely but opaquely identify a single message. RFC 4949 recommends avoiding the term ''message integrity code'' (MIC), and instead using '' checksum'', ''error detection code'', ''hash'', ''keyed hash'', ''message authentication code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JSON Web Token
JSON Web Token (JWT, pronounced , same as the word "jot") is a proposed Internet standard for creating data with optional signature and/or optional encryption whose payload holds JSON that asserts some number of claims. The tokens are signed either using a private secret or a public/private key. For example, a server could generate a token that has the claim "logged in as administrator" and provide that to a client. The client could then use that token to prove that it is logged in as admin. The tokens can be signed by one party's private key (usually the server's) so that any party can subsequently verify whether or not the token is legitimate. If the other party, by some suitable and trustworthy means, is in possession of the corresponding public key, they too are able to verify the token's legitimacy. The tokens are designed to be compact, URL-safe, and usable especially in a web-browser single-sign-on (SSO) context. JWT claims can typically be used to pass identit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Hash Function
A cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with fixed size of n bits) that has special properties desirable for cryptography: * the probability of a particular n-bit output result ( hash value) for a random input string ("message") is 2^ (like for any good hash), so the hash value can be used as a representative of the message; * finding an input string that matches a given hash value (a ''pre-image'') is unfeasible, unless the value is selected from a known pre-calculated dictionary (" rainbow table"). The ''resistance'' to such search is quantified as security strength, a cryptographic hash with n bits of hash value is expected to have a ''preimage resistance'' strength of n bits. A ''second preimage'' resistance strength, with the same expectations, refers to a similar problem of finding a second message that matches the given hash value when one message is already known; * finding any pair of different m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Extension Attack
In cryptography and computer security, a length extension attack is a type of attack where an attacker can use Hash(''message1'') and the length of ''message1'' to calculate Hash(''message1'' ‖ ''message2'') for an attacker-controlled ''message2'', without needing to know the content of ''message1''. This is problematic when the hash is used as a message authentication code with construction Hash(''secret'' ‖ ''message''), and ''message'' and the length of ''secret'' is known, because an attacker can include extra information at the end of the message and produce a valid hash without knowing the secret. Algorithms like MD5, SHA-1 and most of SHA-2 that are based on the Merkle–Damgård construction are susceptible to this kind of attack. Truncated versions of SHA-2, including SHA-384 and SHA-512/256 are not susceptible, nor is the SHA-3 algorithm. HMAC In cryptography, an HMAC (sometimes expanded as either keyed-hash message authentication code or hash-based messag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Length Extension Attack
In cryptography and computer security, a length extension attack is a type of attack where an attacker can use Hash(''message1'') and the length of ''message1'' to calculate Hash(''message1'' ‖ ''message2'') for an attacker-controlled ''message2'', without needing to know the content of ''message1''. This is problematic when the hash is used as a message authentication code with construction Hash(''secret'' ‖ ''message''), and ''message'' and the length of ''secret'' is known, because an attacker can include extra information at the end of the message and produce a valid hash without knowing the secret. Algorithms like MD5, SHA-1 and most of SHA-2 that are based on the Merkle–Damgård construction are susceptible to this kind of attack. Truncated versions of SHA-2, including SHA-384 and SHA-512/256 are not susceptible, nor is the SHA-3 algorithm. HMAC In cryptography, an HMAC (sometimes expanded as either keyed-hash message authentication code or hash-based messag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugo Krawczyk
Hugo Krawczyk is an Argentine-Israeli cryptographer best known for co-inventing the HMAC message authentication algorithm and contributing in fundamental ways to the cryptographic architecture of central Internet standards, including IPsec, IKE, and SSL/TLS, in particular, both IKEv2 and TLS 1.3 use Krawczyk’s SIGMA protocol as the cryptographic core of their key exchange procedures. He has also contributed foundational work in the areas of threshold and proactive cryptosystems and searchable symmetric encryption, among others. Education Krawczyk acquired a Bachelor of Arts in Mathematics from the University of Haifa. Later he received his Master of Science and Ph.D. in Computer Science from Technion - Israel Institute of Technology with Oded Goldreich as doctoral thesis advisor. Career Hugo Krawczyk is a Research Fellow at the Algorand Foundation. Prior to that, he was an IBM Fellow and Distinguished Research Staff Member at the IBM T.J. Watson Research Center in New Y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mihir Bellare
Mihir Bellare is a cryptographer and professor at the University of California San Diego. He has published several seminal papers in the field of cryptography (notably in the area of provable security), many of which were co-written with Phillip Rogaway. Bellare has published a number of papers in the field of Format-Preserving Encryption. His students include Michel Abdalla, Chanathip Namprempre, Tadayoshi Kohno and Anton Mityagin. Bellare is one of the authors of skein. In 2003 Bellare was a recipient of RSA's Sixth Annual Conference Award for outstanding contributions in the field of mathematics for his research in cryptography. In 2013 he became a Fellow of the Association for Computing Machinery. In 2019 he was awarded Levchin Prize for Real-World Cryptography for his outstanding contributions to the design and analysis of real-world cryptosystems, including the development of random oracle model, modes of operation, HMAC, and models for key exchange. Bellare's papers cover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SHA-2
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression function itself built using the Davies–Meyer structure from a specialized block cipher. SHA-2 includes significant changes from its predecessor, SHA-1. The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256. SHA-256 and SHA-512 are novel hash functions computed with eight 32-bit and 64-bit words, respectively. They use different shift amounts and additive constants, but their structures are otherwise virtually identical, differing only in the number of rounds. SHA-224 and SHA-384 are truncated versions of SHA-256 and SHA-512 respectively, computed with different initial values. SHA-512/224 and SHA-512/256 are also t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SHA-1
In cryptography, SHA-1 (Secure Hash Algorithm 1) is a cryptographically broken but still widely used hash function which takes an input and produces a 160- bit (20- byte) hash value known as a message digest – typically rendered as 40 hexadecimal digits. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard. Since 2005, SHA-1 has not been considered secure against well-funded opponents; as of 2010 many organizations have recommended its replacement. NIST formally deprecated use of SHA-1 in 2011 and disallowed its use for digital signatures in 2013, and declared that it should be phased out by 2030. , chosen-prefix attacks against SHA-1 are practical. As such, it is recommended to remove SHA-1 from products as soon as possible and instead use SHA-2 or SHA-3. Replacing SHA-1 is urgent where it is used for digital signatures. All major web browser vendors ceased acceptance of SHA-1 SSL certificates in 2017 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
