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Movements, leaders, victories and the continuing fight for equality.
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In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
In computer security, an access-control list (ACL) is a list of permissions[a] associated with a system resource (object or facility). An ACL specifies which users or system processes are granted access to resources, as well as what operations are allowed on given resources.[1] Each entry in a typical ACL specifies a subject and an operation. For instance,
Many kinds of operating systems implement ACLs or have a historical implementation; the first implementation of ACLs was in the filesystem of Multics in 1965.[2][3]
A filesystem ACL is a data structure (usually a table) containing entries that specify individual user or group rights to specific system objects such as programs, processes, or files. These entries are known as access-control entries (ACEs) in the Microsoft Windows NT,[4] OpenVMS, and Unix-like operating systems such as Linux, macOS, and Solaris. Each accessible object contains an identifier to its ACL. The privileges or permissions determine specific access rights, such as whether a user can read from, write to, or execute an object. In some implementations, an ACE can control whether or not a user, or group of users, may alter the ACL on an object.
One of the first operating systems to provide filesystem ACLs was Multics. PRIMOS featured ACLs at least as early as 1984.[5]
In the 1990s the ACL and role-based access control (RBAC) models were extensively tested[by whom?] and used to administer file permissions.
POSIX 1003.1e/1003.2c working group made an effort to standardize ACLs, resulting in what is now known as "POSIX.1e ACL" or simply "POSIX ACL".[6] The POSIX.1e/POSIX.2c drafts were withdrawn in 1997 due to participants losing interest for funding the project and turning to more powerful alternatives such as NFSv4 ACLs.[7] As of December 2019[update], no live sources of the draft could be found on the Internet, but it can still be found in the Internet Archive.[8]
Most of the Unix and Unix-like operating systems (e.g. Linux since 2.5.46 or November 2002,[9] FreeBSD, or Solaris) support POSIX.1e ACLs (not necessarily draft 17). ACLs are usually stored in the extended attributes of a file on these systems.
NFSv4 ACLs are much more powerful than POSIX draft ACLs. Unlike draft POSIX ACLs, NFSv4 ACLs are defined by a published standard, as part of the Network File System.
NFSv4 ACLs are supported by many Unix and Unix-like operating systems. Examples include AIX, FreeBSD,[10] Mac OS X beginning with version 10.4 ("Tiger"), or Solaris with ZFS filesystem,[11] support NFSv4 ACLs, which are part of the NFSv4 standard. There are two experimental implementations of NFSv4 ACLs for Linux: NFSv4 ACLs support for Ext3 filesystem[12] and the more recent Richacls, which brings NFSv4 ACLs support for Ext4 filesystem.[13] As with POSIX ACLs, NFSv4 ACLs are usually stored as extended attributes on Unix-like systems.
NFSv4 ACLs are organized nearly identically to the Windows NT ACLs used in NTFS.[14] NFSv4.1 ACLs are a superset of both NT ACLs and POSIX draft ACLs.[15] Samba supports saving the NT ACLs of SMB-shared files in many ways, one of which is as NFSv4-encoded ACLs.[16]
Microsoft's Active Directory service implements an LDAP server that stores and disseminates configuration information about users and computers in a domain.[17] Active Directory extends the LDAP specification by adding the same type of access-control list mechanism as Windows NT uses for the NTFS filesystem. Windows 2000 then extended the syntax for access-control entries such that they could not only grant or deny access to entire LDAP objects, but also to individual attributes within these objects.[18]
On some types of proprietary computer hardware (in particular, routers and switches), an access-control list provides rules that are applied to port numbers or IP addresses that are available on a host or other layer 3, each with a list of hosts and/or networks permitted to use the service. Although it is additionally possible to configure access-control lists based on network domain names, this is a questionable idea because individual TCP, UDP, and ICMP headers do not contain domain names. Consequently, the device enforcing the access-control list must separately resolve names to numeric addresses. This presents an additional attack surface for an attacker who is seeking to compromise security of the system which the access-control list is protecting. Both individual servers and routers can have network ACLs. Access-control lists can generally be configured to control both inbound and outbound traffic, and in this context they are similar to firewalls. Like firewalls, ACLs could be subject to security regulations and standards such as PCI DSS.
ACL algorithms have been ported to SQL and to relational database systems. Many "modern" (2000s and 2010s) SQL-based systems, like enterprise resource planning and content management systems, have used ACL models in their administration modules.
In 2024, schema-indexed ACL models emerged as a lightweight alternative to traditional JSON-based permission storage. One notable proposal introduced the idea of storing only the indexes of allowed operations, rather than full permission trees. This technique, later formalized as SCode ACL, allows compact encoding of access rights (e.g., `"0 2 5"`) based on a predefined flattened schema, making it particularly efficient for use in stateless systems such as JWT tokens or session cookies. The approach gained early traction in developer communities for its minimalism and performance, and has since been adopted in both small-scale and production-grade systems.[citation needed]
The main alternative to the ACL model is the role-based access-control (RBAC) model. A "minimal RBAC model", RBACm, can be compared with an ACL mechanism, ACLg, where only groups are permitted as entries in the ACL. Barkley (1997)[19] showed that RBACm and ACLg are equivalent.
In modern SQL implementations, ACLs also manage groups and inheritance in a hierarchy of groups. So "modern ACLs" can express all that RBAC express and are notably powerful (compared to "old ACLs") in their ability to express access-control policy in terms of the way in which administrators view organizations.
For data interchange, and for "high-level comparisons", ACL data can be translated to XACML.[20]
The new version of Gnet-II (revision 3.0) has added a line-security mechanism which is implemented under the Primos ACL subsystem.
EA (Extended Attributes) and ACL (Access Control Lists) functionality is now available for ext3 file systems. In addition, ACL functionality is available for NFS.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
In computer security, an access-control list (ACL) is a list of permissions associated with a system resource (object or facility). An ACL specifies which users or system processes are granted access to resources, as well as what operations are allowed on given resources. Each entry in a typical ACL specifies a subject and an operation. For instance, If a file object has an ACL that contains(Alice: read,write; Bob: read), this would give Alice permission to read and write the file and give Bob permission only to read it. If the Resource Access Control Facility (RACF) profile CONSOLE CLASS(TSOAUTH) has an ACL that contains(ALICE:READ), this would give ALICE permission to use the TSO CONSOLE command.
A VLAN access control list (VACL) provides access control for all packets that are bridged within a VLAN or that are routed into or out of a VLAN. Unlike regular Cisco IOS access control lists that are configured on router interfaces and applied on routed packets only, VACLs apply to all packets. The technology was developed by Cisco on the Catalyst 6500 Series switch platform. VACLs may be used in similar fashion to a SPAN port or network tap, as a way to replicate computer network data that is coming into and leaving from a computer or a network. This is useful if you want to monitor traffic. Often, this configuration is used to facilitate data loss prevention (DLP) or network-based intrusion prevention systems. VACL or VACL Ports can be much more discriminating of the traffic they forward compared to a standard SPAN port. They may be set to only forward specific types or specific VLANs to the monitoring port. However, they forward all traffic that matches the criteria, as they do not have the functionality to select from ingress or egress traffic like SPAN ports.
In computer science, an access control matrix or access matrix is an abstract, formal security model of protection state in computer systems, that characterizes the rights of each subject with respect to every object in the system. It was first introduced by Butler W. Lampson in 1971. An access matrix can be envisioned as a rectangular array of cells, with one row per subject and one column per object. The entry in a cell – that is, the entry for a particular subject-object pair – indicates the access mode that the subject is permitted to exercise on the object. Each column is equivalent to an access control list for the object; and each row is equivalent to an access profile for the subject.
An access badge is a credential used to gain entry to an area having automated access control entry points. Entry points may be doors, turnstiles, parking gates or other barriers. Access badges use various technologies to identify the holder of the badge to an access control system. The most common technologies are magnetic stripe, proximity, barcode, smart cards and various biometric devices. The magnetic stripe ID card was invented by Forrest Parry in 1960. The access badge contains a number that is read by a card reader. This number is usually called the facility code and is programmed by the administrator. The number is sent to an access control system, a computer system that makes access control decisions based on information about the credential. If the credential is included in an access control list, the access control system unlocks the controlled access point. The transaction is stored in the system for later retrieval; reports can be generated showing the date/time the card was used to enter the controlled access point. The Wiegand effect was used in early access cards. This method was abandoned in favor of other proximity technologies. The new technologies retained the Wiegand upstream data so that the new readers were compatible with old systems. Readers are still called Wiegand but no longer use the Wiegand effect. A Wiegand reader radiates a 1" to 5" electrical field around itself. Cards use a simple LC circuit. When a card is presented to the reader, the reader's electrical field excites a coil in the card. The coil charges a capacitor and in turn powers an integrated circuit. The integrated circuit outputs the card number to the coil which transmits it to the reader. The transmission of the card number happens in the clear—it is not encrypted. With basic understanding of radio technology and of card formats, Wiegand proximity cards can be hacked. A common proximity format is 26 bit Wiegand. This format uses a facility code, also called a site code. The facility code is a unique number common to all of the cards in a particular set. The idea is an organization has their own facility code and then numbered cards incrementing from 1. Another organization has a different facility code and their card set also increments from 1. Thus different organizations can have card sets with the same card numbers but since the facility codes differ, the cards only work at one organization. This idea worked fine for a while but there is no governing body controlling card numbers, different manufacturers can supply cards with identical facility codes and identical card numbers to different organizations. Thus there is a problem of duplicate cards. To counteract this problem some manufacturers have created formats beyond 26 bit Wiegand that they control and issue to an organization. In the 26 bit Wiegand format bit 1 is an even parity bit. Bits 2-9 are a facility code. Bits 10-25 are the card number. Bit 26 is an odd parity bit. Other formats have a similar structure of leading facility code followed by card number and including parity bits for error checking. Smart cards can be used to counteract the problems of transmitting card numbers in the clear and control of the card numbers by manufacturers. Smart cards can be encoded by organizations with unique numbers and the communication between card and reader can be encrypted.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Brown v. Board of Education in 1954.
