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AEAD
Authenticated Encryption (AE) is an encryption scheme which simultaneously assures the data confidentiality (also known as privacy: the encrypted message is impossible to understand without the knowledge of a secret key) and authenticity (in other words, it is unforgeable: the encrypted message includes an authentication tag that the sender can calculate only while possessing the secret key). Examples of encryption modes that provide AE are GCM, CCM. Many (but not all) AE schemes allow the message to contain "associated data" (AD) which is not made confidential, but its integrity is protected (i.e., it is readable, but tampering with it will be detected). A typical example is the header of a network packet that contains its destination address. To properly route the packet, all intermediate nodes in the message path need to know the destination, but for security reasons they cannot possess the secret key. Schemes that allow associated data provide authenticated encryption wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption Mode
In cryptography, a block cipher mode of operation is an algorithm that uses a block cipher to provide information security such as confidentiality or authenticity. A block cipher by itself is only suitable for the secure cryptographic transformation (encryption or decryption) of one fixed-length group of bits called a block. A mode of operation describes how to repeatedly apply a cipher's single-block operation to securely transform amounts of data larger than a block. Most modes require a unique binary sequence, often called an initialization vector (IV), for each encryption operation. The IV must be non-repeating, and for some modes must also be random. The initialization vector is used to ensure that distinct ciphertexts are produced even when the same plaintext is encrypted multiple times independently with the same key. Block ciphers may be capable of operating on more than one block size, but during transformation the block size is always fixed. Block cipher modes op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EAX Mode
EAX mode (encrypt-then-authenticate-then-translate) is a mode of operation for cryptographic block ciphers. It is an Authenticated Encryption with Associated Data ( AEAD) algorithm designed to simultaneously provide both authentication and privacy Privacy (, ) is the ability of an individual or group to seclude themselves or information about themselves, and thereby express themselves selectively. The domain of privacy partially overlaps with security, which can include the concepts of a ... of the message ( authenticated encryption) with a two-pass scheme, one pass for achieving privacy and one for authenticity for each block. EAX mode was submitted on October 3, 2003, to the attention of NIST in order to replace CCM as standard AEAD mode of operation, since CCM mode lacks some desirable attributes of EAX and is more complex. Encryption and authentication EAX is a flexible nonce-using two-pass AEAD scheme with no restrictions on block cipher primitive to be used, nor o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ChaCha20-Poly1305
ChaCha20-Poly1305 is an authenticated encryption with associated data (AEAD) algorithm, that combines the ChaCha20 stream cipher with the Poly1305 message authentication code. It has fast software performance, and without hardware acceleration, is usually faster than AES-GCM. History The two building blocks of the construction, the algorithms Poly1305 and ChaCha20, were both independently designed, in 2005 and 2008, by Daniel J. Bernstein. In March 2013, a proposal was made to the IETF TLS working group to include Salsa20, a winner of the eSTREAM competition to replace the aging RC4-based ciphersuites. A discussion followed in the IETF TLS mailing list with various enhancement suggestions, including using Chacha20 instead of Salsa20 and using a universal hashing based MAC for performance. The outcome of this process was the adoption of Adam Langley's proposal for a variant of the original ChaCha20 algorithm (using 32-bit counter and 96-bit nonce) and a variant of the origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OCB Mode
Offset codebook mode (OCB mode) is an authenticated encryption mode of operation for cryptographic block ciphers. OCB mode was designed by Phillip Rogaway, who credits Mihir Bellare, John Black, and Ted Krovetz with assistance and comments on the designs. It is based on the '' integrity-aware parallelizeable mode'' (IAPM) of authenticated encryption by Charanjit S. Jutla. The ''OCB2'' version was proven insecure, while the original ''OCB1'' as well as ''OCB3'' from 2011 are still considered secure. Encryption and authentication OCB mode was designed to provide both message authentication and privacy. It is essentially a scheme for integrating a message authentication code (MAC) into the operation of a block cipher. In this way, OCB mode avoids the need to use two systems: a MAC for authentication and encryption for confidentiality. This results in lower computational cost compared to using separate encryption and authentication functions. There are three versions of OC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCM Mode
CCM mode (counter with cipher block chaining message authentication code; counter with CBC-MAC) is a mode of operation for cryptographic block ciphers. It is an authenticated encryption algorithm designed to provide both authentication and confidentiality. CCM mode is only defined for block ciphers with a block length of 128 bits. The nonce of CCM must be carefully chosen to never be used more than once for a given key. This is because CCM is a derivation of counter (CTR) mode and the latter is effectively a stream cipher. Encryption and authentication As the name suggests, CCM mode combines counter (CTR) mode for confidentiality with cipher block chaining message authentication code (CBC-MAC) for authentication. These two primitives are applied in an "authenticate-then-encrypt" manner: CBC-MAC is first computed on the message to obtain a message authentication code (MAC), then the message and the MAC are encrypted using counter mode. The main insight is that the same ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galois/Counter Mode
In cryptography, Galois/Counter Mode (GCM) is a mode of operation for symmetric-key cryptographic block ciphers which is widely adopted for its performance. GCM throughput rates for state-of-the-art, high-speed communication channels can be achieved with inexpensive hardware resources. The GCM algorithm provides both data authenticity (integrity) and confidentiality and belongs to the class of authenticated encryption with associated data (AEAD) methods. This means that as input it takes a key K, some plaintext P, and some associated data AD; it then encrypts the plaintext using the key to produce ciphertext C, and computes an authentication tag T from the ciphertext and the associated data (which remains unencrypted). A recipient with knowledge of K, upon reception of AD, C and T, can decrypt the ciphertext to recover the plaintext P and can check the tag T to ensure that neither ciphertext nor associated data were tampered with. GCM uses a block cipher with block size 128 bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAPM (mode)
Integrity-aware parallelizable mode (IAPM) is a mode of operation for cryptographic block ciphers. As its name implies, it allows for a parallel mode of operation for higher throughput. Encryption and authentication At the time of its creation, IAPM was one of the first cipher modes to provide both authentication and privacy in a single pass. (In earlier authenticated encryption designs, two passes would be required to: one to encrypt, and the second to compute a MAC.) IAPM was proposed for use in IPsec. Other AEAD schemes also provide all of the single pass, privacy and authentication properties. IAPM has mostly been supplanted by Galois/counter mode. See also * OCB mode Offset codebook mode (OCB mode) is an authenticated encryption mode of operation for cryptographic block ciphers. OCB mode was designed by Phillip Rogaway, who credits Mihir Bellare, John Black, and Ted Krovetz with assistance and comments o ... IAPM modedescribed in more detail in Hebrew Wik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Key Wrap
In cryptography, key wrap constructions are a class of symmetric encryption algorithms designed to encapsulate (encrypt) cryptographic key material. The Key Wrap algorithms are intended for applications such as protecting keys while in untrusted storage or transmitting keys over untrusted communications networks. The constructions are typically built from standard primitives such as block ciphers and cryptographic hash functions. Key Wrap may be considered as a form of key encapsulation algorithm, although it should not be confused with the more commonly known ''asymmetric'' (public-key) key encapsulation algorithms (e.g., PSEC-KEM). Key Wrap algorithms can be used in a similar application: to securely transport a session key by encrypting it under a long-term encryption key. Background In the late 1990s, the National Institute of Standards and Technology (NIST) posed the "Key Wrap" problem: to develop secure and efficient cipher-based key encryption algorithms. The result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
