YAK (cryptography)

	YAK (cryptography) The YAK is a public-key authenticated key-agreement protocol, proposed by Feng Hao in 2010. It is claimed to be the simplest authenticated key exchange protocol among the related schemes, including MQV, HMQV, Station-to-Station protocol, SSL/ TLS etc. The authentication is based on public key pairs. As with other protocols, YAK normally requires a Public Key Infrastructure to distribute authentic public keys to the communicating parties. The security of YAK is disputed (see below and the talk page). Description Two parties, Alice and Bob, agree on a group G with generator g of prime order q in which the discrete log problem is hard. Typically a Schnorr group is used. In general, YAK can use any prime order group that is suitable for public key cryptography, including elliptic curve cryptography. Let g^a be Alice's long-term public key and g^b be Bob's. The protocol executes in one round: Alice selects x \in_\text , q-1/math> and sends out g^x together with a zero-knowledge proof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Key-agreement Protocol In cryptography, a key-agreement protocol is a protocol whereby two or more parties can agree on a key in such a way that both influence the outcome. If properly done, this precludes undesired third parties from forcing a key choice on the agreeing parties. Protocols that are useful in practice also do not reveal to any eavesdropping party what key has been agreed upon. Many key exchange systems have one party generate the key, and simply send that key to the other party—the other party has no influence on the key. Using a key-agreement protocol avoids some of the key distribution problems associated with such systems. Protocols where both parties influence the final derived key are the only way to implement perfect forward secrecy. Exponential key exchange The first publicly knownSee Diffie–Hellman key exchange for a more complete history of both the secret and public development of public-key cryptography. public-key agreement protocol that meets the above criteria was the Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Station-to-Station Protocol In public-key cryptography, the Station-to-Station (STS) protocol is a cryptographic key agreement scheme. The protocol is based on classic Diffie–Hellman, and provides mutual key and entity authentication. Unlike the classic Diffie–Hellman, which is not secure against a man-in-the-middle attack, this protocol assumes that the parties have signature keys, which are used to sign messages, thereby providing security against man-in-the-middle attacks. In addition to protecting the established key from an attacker, the STS protocol uses no timestamps and provides perfect forward secrecy. It also entails two-way explicit key confirmation, making it an ''authenticated key agreement with key confirmation'' (AKC) protocol. STS was originally presented in 1987 in the context of ISDN security , finalized in 1989 and generally presented by Whitfield Diffie, Paul C. van Oorschot and Michael J. Wiener in 1992. The historical context for the protocol is also discussed in . Description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Secure Sockets Layer 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 the cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	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 the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Public Key Infrastructure A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred. In cryptography, a PKI is an arrangement that ''binds'' public keys with respective identities of entities (like people and organizations). The binding is established through a process of registration and issuance of certificates at and by a certificate authority (CA). Depending on the assurance level of the binding, this may be carried out by an automa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	YAK (cryptography) The YAK is a public-key authenticated key-agreement protocol, proposed by Feng Hao in 2010. It is claimed to be the simplest authenticated key exchange protocol among the related schemes, including MQV, HMQV, Station-to-Station protocol, SSL/ TLS etc. The authentication is based on public key pairs. As with other protocols, YAK normally requires a Public Key Infrastructure to distribute authentic public keys to the communicating parties. The security of YAK is disputed (see below and the talk page). Description Two parties, Alice and Bob, agree on a group G with generator g of prime order q in which the discrete log problem is hard. Typically a Schnorr group is used. In general, YAK can use any prime order group that is suitable for public key cryptography, including elliptic curve cryptography. Let g^a be Alice's long-term public key and g^b be Bob's. The protocol executes in one round: Alice selects x \in_\text , q-1/math> and sends out g^x together with a zero-knowledge proof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Schnorr Group A Schnorr group, proposed by Claus P. Schnorr, is a large prime-order subgroup of \mathbb_p^\times, the multiplicative group of integers modulo p for some prime p. To generate such a group, generate p, q, r such that :p = qr + 1 with p, q prime. Then choose any h in the range 1 < h < p until you find one such that : $h^r \not\equiv 1\;(\text\;p)$ . This value : $g = h^r\textp$ is a generator of a subgroup of $\mathbb_p^\times$ of order $q$ . Schnorr groups are useful in discrete log based cryptosystems including Schnorr signatures and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Elliptic Curve Cryptography Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provide equivalent security.Commercial National Security Algorithm Suite and Quantum Computing FAQ U.S. National Security Agency, January 2016. Elliptic curves are applicable for key agreement , digital signature s, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Zero-knowledge Proof In cryptography, a zero-knowledge proof or zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that a given statement is true while the prover avoids conveying any additional information apart from the fact that the statement is indeed true. The essence of zero-knowledge proofs is that it is trivial to prove that one possesses knowledge of certain information by simply revealing it; the challenge is to prove such possession without revealing the information itself or any additional information. If proving a statement requires that the prover possess some secret information, then the verifier will not be able to prove the statement to anyone else without possessing the secret information. The statement being proved must include the assertion that the prover has such knowledge, but without including or transmitting the knowledge itself in the assertion. Otherwise, the statement would not be proved in zero-knowledge because it ... [...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 messa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Non-interactive Zero-knowledge Proof Non-interactive zero-knowledge proofs are zero-knowledge proofs where information between a prover and a verifier can be authenticated by the prover, without revealing any of the specific information beyond the validity of the transaction itself. This function of encryption makes direct communication between the prover and verifier unnecessary, effectively removing any intermediaries. The core trustless cryptography "proofing" involves a hash function generation of a random number, constrained within mathematical parameters (primarily to modulate hashing difficulties) determined by the prover and verifier. With this cryptographic engine, the prover must demonstrate the validity of the transaction, by solving the hash of a random number. Finally, proof of the answer is returned to the verifier, without revealing its value. There are many different methods for establishing a cryptographic proof of hash validity. Perhaps the most notable method, proof of work, involves computing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Forward Secrecy In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key agreement protocols that gives assurances that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised. For HTTPS, the long-term secret is typically the private key of the server. Forward secrecy protects past sessions against future compromises of keys or passwords. By generating a unique session key for every session a user initiates, the compromise of a single session key will not affect any data other than that exchanged in the specific session protected by that particular key. This by itself is not sufficient for forward secrecy which additionally requires that a long-term secret compromise does not affect the security of past session keys. Forward secrecy protects data on the transport layer of a network that uses common Transport Layer Security protocols, including OpenSSL, when its long-term secret keys are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]