Misplaced Pages

#641358

32-652: The Competition for Authenticated Encryption: Security, Applicability, and Robustness ( CAESAR ) is a competition organized by a group of international cryptologic researchers to encourage the design of authenticated encryption schemes. The competition was announced at the Early Symmetric Crypto workshop in January 2013 and the final portfolio in February 2019. The final CAESAR portfolio is organized into three use cases: The final portfolio announced by

64-440: A clustered file system , using file systems that employ block level checksums such as ZFS , storage arrays that compute parity calculations such as exclusive or or use a cryptographic hash function and even having a watchdog timer on critical subsystems. Physical integrity often makes extensive use of error detecting algorithms known as error-correcting codes . Human-induced data integrity errors are often detected through

96-524: A computer file system may be configured on a fault-tolerant RAID array, but might not provide block-level checksums to detect and prevent silent data corruption . As another example, a database management system might be compliant with the ACID properties, but the RAID controller or hard disk drive's internal write cache might not be. This type of integrity is concerned with the correctness or rationality of

128-413: A data value is derived based on algorithm, contributors and conditions. It also specifies the conditions on how the data value could be re-derived. Data integrity is normally enforced in a database system by a series of integrity constraints or rules. Three types of integrity constraints are an inherent part of the relational data model : entity integrity, referential integrity and domain integrity. If

160-412: A database correctly rejecting mutually exclusive possibilities). Moreover, upon later retrieval , ensure the data is the same as when it was originally recorded. In short, data integrity aims to prevent unintentional changes to information. Data integrity is not to be confused with data security , the discipline of protecting data from unauthorized parties. Any unintended changes to data as the result of

192-587: A database supports these features, it is the responsibility of the database to ensure data integrity as well as the consistency model for the data storage and retrieval. If a database does not support these features, it is the responsibility of the applications to ensure data integrity while the database supports the consistency model for the data storage and retrieval. Having a single, well-controlled, and well-defined data-integrity system increases: Modern databases support these features (see Comparison of relational database management systems ), and it has become

224-519: A message and subsequently applying a MAC to the ciphertext (the Encrypt-then-MAC approach) implies security against an adaptive chosen ciphertext attack , provided that both functions meet minimum required properties. Katz and Yung investigated the notion under the name "unforgeable encryption" and proved it implies security against chosen ciphertext attacks. In 2013, the CAESAR competition

256-722: A piece of data, given a particular context. This includes topics such as referential integrity and entity integrity in a relational database or correctly ignoring impossible sensor data in robotic systems. These concerns involve ensuring that the data "makes sense" given its environment. Challenges include software bugs , design flaws, and human errors. Common methods of ensuring logical integrity include things such as check constraints , foreign key constraints , program assertions , and other run-time sanity checks. Physical and logical integrity often share many challenges such as human errors and design flaws, and both must appropriately deal with concurrent requests to record and retrieve data,

288-474: A poor protocol design or implementation turning Alice's side into an oracle . Naturally, this attack cannot be mounted at all when the keys are generated randomly. Key commitment was originally studied in the 2010s by Abdalla et al. and Farshim et al. under the name "robust encryption". To mitigate the attack described above without removing the "oracle", a key-committing AEAD that does not allow this type of crafted messages to exist can be used. AEGIS

320-419: A second (wrong) key K M will be incorrect, the authentication tag would still match. Since crafting a message with such property requires Mallory to already possess both K A and K M , the issue might appear to be one of a purely academic interest. However, under special circumstances, practical attacks can be mounted against vulnerable implementations. For example, if an identity authentication protocol

352-407: A storage, retrieval or processing operation, including malicious intent, unexpected hardware failure, and human error , is failure of data integrity. If the changes are the result of unauthorized access, it may also be a failure of data security. Depending on the data involved this could manifest itself as benign as a single pixel in an image appearing a different color than was originally recorded, to

SECTION 10

#1732797507642

384-562: Is an example fast (if the AES instruction set is present), key-committing AEAD. It is possible to add key-commitment to an existing AEAD scheme. The plaintext is first encrypted, then a MAC is produced based on the resulting ciphertext. The ciphertext and its MAC are sent together. ETM is the standard method according to ISO/IEC 19772:2009. It is the only method which can reach the highest definition of security in AE, but this can only be achieved when

416-483: Is based on successful decryption of a message that uses a password-based key, Mallory's ability to craft a single message that would be successfully decrypted using 1000 different keys associated with weak , and thus known to her, potential passwords, can speed up her search for passwords by a factor of almost 1000. For this dictionary attack to succeed, Mallory also needs an ability to distinguish successful decryption by Alice from an unsuccessful one, due, for example, to

448-436: Is broad in scope and may have widely different meanings depending on the specific context even under the same general umbrella of computing . It is at times used as a proxy term for data quality , while data validation is a prerequisite for data integrity. Data integrity is the opposite of data corruption . The overall intent of any data integrity technique is the same: ensure data is recorded exactly as intended (such as

480-424: Is unnecessary, but authenticity is desired. The need for authenticated encryption emerged from the observation that securely combining separate confidentiality and authentication block cipher operation modes could be error prone and difficult. This was confirmed by a number of practical attacks introduced into production protocols and applications by incorrect implementation, or lack of authentication. Around

512-572: The CAESAR committee is: The committee in charge of the CAESAR Competition consisted of: Authenticated encryption 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

544-703: The E&;M approach has not been proved to be strongly unforgeable in itself, it is possible to apply some minor modifications to SSH to make it strongly unforgeable despite the approach. A MAC is produced based on the plaintext, then the plaintext and MAC are together encrypted to produce a ciphertext based on both. The ciphertext (containing an encrypted MAC) is sent. Until TLS 1.2, all available SSL/TLS cipher suites were MtE. MtE has not been proven to be strongly unforgeable in itself. The SSL/TLS implementation has been proven to be strongly unforgeable by Krawczyk who showed that SSL/TLS was, in fact, secure because of

576-478: The MAC used is "strongly unforgeable". IPSec adopted EtM in 2005. In November 2014, TLS and DTLS received extensions for EtM with RFC   7366 . Various EtM ciphersuites exist for SSHv2 as well (e.g., hmac-sha1-etm@openssh.com ). A MAC is produced based on the plaintext, and the plaintext is encrypted without the MAC. The plaintext's MAC and the ciphertext are sent together. Used in, e.g., SSH . Even though

608-474: The block size of the encryption function. Padding errors often result in the detectable errors on the recipient's side, which in turn lead to padding oracle attacks, such as Lucky Thirteen . Data integrity Data integrity is the maintenance of, and the assurance of, data accuracy and consistency over its entire life-cycle . It is a critical aspect to the design, implementation, and usage of any system that stores, processes, or retrieves data. The term

640-749: The database itself, which automatically ensures the accuracy and integrity of the data so that no child record can exist without a parent (also called being orphaned) and that no parent loses their child records. It also ensures that no parent record can be deleted while the parent record owns any child records. All of this is handled at the database level and does not require coding integrity checks into each application. Various research results show that neither widespread filesystems (including UFS , Ext , XFS , JFS and NTFS ) nor hardware RAID solutions provide sufficient protection against data integrity problems. Some filesystems (including Btrfs and ZFS ) provide internal data and metadata checksumming that

672-405: The de facto responsibility of the database to ensure data integrity. Companies, and indeed many database systems, offer products and services to migrate legacy systems to modern databases. An example of a data-integrity mechanism is the parent-and-child relationship of related records. If a parent record owns one or more related child records all of the referential integrity processes are handled by

SECTION 20

#1732797507642

704-500: The encoding used alongside the MtE mechanism. However, Krawczyk's proof contains flawed assumptions about the randomness of the initialization vector (IV). The 2011 BEAST attack exploited the non-random chained IV and broke all CBC algorithms in TLS 1.0 and under. In addition, deeper analysis of SSL/TLS modeled the protection as MAC-then-pad-then-encrypt, i.e. the plaintext is first padded to

736-512: The integrity of both the associated data and the confidential information in a message. AD is useful, for example, in network packets where the header should be visible for routing , but the payload needs to be confidential, and both need integrity and authenticity . The notion of AEAD was formalized by Rogaway (2002). AE was originally designed primarily to provide the ciphertext integrity: successful validation of an authentication tag by Alice using her symmetric key K A indicates that

768-514: The latter of which is entirely a subject on its own. If a data sector only has a logical error, it can be reused by overwriting it with new data. In case of a physical error, the affected data sector is permanently unusable. Data integrity contains guidelines for data retention , specifying or guaranteeing the length of time data can be retained in a particular database (typically a relational database ). To achieve data integrity, these rules are consistently and routinely applied to all data entering

800-728: The loss of vacation pictures or a business-critical database, to even catastrophic loss of human life in a life-critical system . Physical integrity deals with challenges which are associated with correctly storing and fetching the data itself. Challenges with physical integrity may include electromechanical faults, design flaws, material fatigue , corrosion , power outages , natural disasters, and other special environmental hazards such as ionizing radiation , extreme temperatures, pressures and g-forces . Ensuring physical integrity includes methods such as redundant hardware, an uninterruptible power supply , certain types of RAID arrays, radiation hardened chips, error-correcting memory , use of

832-416: The message was not tampered with by an adversary Mallory that does not possess the K A . The AE schemes usually do not provide the key commitment , a guarantee that the decryption would fail for any other key. As of 2021, most existing AE schemes (including the very popular GCM) allow some messages to be decoded without an error using more than just the (correct) K A ; while their plaintext decoded using

864-487: 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 with associated data , or AEAD . A typical programming interface for an AE implementation provides the following functions: The header part is intended to provide authenticity and integrity protection for networking or storage metadata for which confidentiality

896-455: The relations a piece of data can have to other pieces of data, such as a Customer record being allowed to link to purchased Products , but not to unrelated data such as Corporate Assets . Data integrity often includes checks and correction for invalid data, based on a fixed schema or a predefined set of rules. An example being textual data entered where a date-time value is required. Rules for data derivation are also applicable, specifying how

928-446: The system, and any relaxation of enforcement could cause errors in the data. Implementing checks on the data as close as possible to the source of input (such as human data entry), causes less erroneous data to enter the system. Strict enforcement of data integrity rules results in lower error rates, and time saved troubleshooting and tracing erroneous data and the errors it causes to algorithms. Data integrity also includes rules defining

960-512: The use of simpler checks and algorithms, such as the Damm algorithm or Luhn algorithm . These are used to maintain data integrity after manual transcription from one computer system to another by a human intermediary (e.g. credit card or bank routing numbers). Computer-induced transcription errors can be detected through hash functions . In production systems, these techniques are used together to ensure various degrees of data integrity. For example,

992-985: The year 2000, a number of efforts evolved around the notion of standardizing modes that ensured correct implementation. In particular, strong interest in possibly secure modes was sparked by the publication of Charanjit Jutla 's integrity-aware CBC and integrity-aware parallelizable , IAPM, modes in 2000 (see OCB and chronology ). Six different authenticated encryption modes (namely offset codebook mode 2.0 , OCB   2.0; Key Wrap ; counter with CBC-MAC , CCM; encrypt then authenticate then translate , EAX; encrypt-then-MAC , EtM; and Galois/counter mode , GCM) have been standardized in ISO/IEC 19772:2009. More authenticated encryption methods were developed in response to NIST solicitation. Sponge functions can be used in duplex mode to provide authenticated encryption. Bellare and Namprempre (2000) analyzed three compositions of encryption and MAC primitives, and demonstrated that encrypting

CAESAR Competition - Misplaced Pages Continue

1024-464: Was announced to encourage design of authenticated encryption modes. In 2015, ChaCha20-Poly1305 is added as an alternative AE construction to GCM in IETF protocols. Authenticated encryption with associated data (AEAD) is a variant of AE that allows the message to include "associated data" (AD, additional non-confidential information, a.k.a. "additional authenticated data", AAD). A recipient can check

#641358