leap


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leap

Music a relatively large melodic interval, esp in a solo part

LEAP

Language for the Expression of Associative Procedures.

ALGOL-based formalism for sets and associative retrieval, for TX-2. Became part of SAIL.

"An ALGOL-based Associative Language", J.A. Feldman et al, CACM 12(8):439-449 (Aug 1969).

EAP

(Extensible Authentication Protocol) A protocol that acts as a framework and transport for other authentication protocols. EAP uses its own start and end messages but then carries any number of third-party messages between the client (supplicant) and access control node such as an access point in a wireless network. See PAP and CHAP.

EAP and LANs


EAP originated with the dial-up PPP protocol in order to support protocols beyond PAP and CHAP. For use on packet networks, EAP Over LAN (EAPOL) was created. EAPOL added new message types and allowed an Ethernet header to be prefixed onto EAP messages so they could be transmitted via Ethernet. Following are various EAP methods used mostly in wireless networks, but also in wired networks. See 802.1X, WPA and 802.11i.

EAP-TLS (EAP-Transport Layer Security)
Uses the handshake protocol in TLS, not its encryption method. Client and server authenticate each other using digital certificates. Client generates a pre-master secret key by encrypting a random number with the server's public key and sends it to the server. Both client and server use the pre-master to generate the same secret key.

EAP-TTLS (EAP-Tunneled TLS)
Like EAP-TLS above except only the server has a certificate to authenticate itself to the client first. As in EAP-TLS, a secure connection (the "tunnel") is established with secret keys, but that connection is used to continue the authentication process by authenticating the client and possibly the server again using any EAP method or legacy method such as PAP and CHAP.

PEAP (Protected EAP)
Similar to EAP-TTLS above except it does not support legacy methods. It only moves EAP frames. Windows XP natively supports PEAP.

LEAP (Light EAP, Cisco LEAP)
From Cisco, first implementation of EAP and 802.1X for wireless networks. Uses preshared keys and MS-CHAP protocol to authenticate client and server to each other. Server generates and sends session key to access point. Client computes session key independently based on data received in the CHAP challenge.

EAP-FAST
(EAP-Flexible Authentication via Secure Tunneling)
Enhancement to LEAP from Cisco that provides an encrypted tunnel to distribute preshared keys known as "Protected Access Credential" (PAC) keys. PAC keys may be continuously refreshed to prevent dictionary attacks. EAP-FAST is defined in Cisco's Cisco Compatible Extensions (see CCX).

EAP-SIM (GSM Cellphones)
For GSM phones that switch between cellular and Wi-Fi networks, depending on which is in range. The Subscriber Identity Module (SIM) smart card in the GSM phone (see GSM) contains the secret key used for challenge/response authentication and deriving session keys for encryption.
References in classic literature ?
To Jane Clayton, waiting in the tree where Werper had placed her, it seemed that the long night would never end, yet end it did at last, and within an hour of the coming of dawn her spirits leaped with renewed hope at sight of a solitary horseman approaching along the trail.
Moving slowly outward upon the two branches Tarzan swung Numa out so that he could not reach the bole of the tree with his raking talons, then he made the rope fast after drawing the lion clear of the ground, dropped his five pigskin sacks to earth and leaped down himself.
He had the brute's eyes to guide his point, and, as true as the sword hand of his mighty sire, his guided the keen point to one of those blazing orbs, even as he leaped lightly to one side.
"Well, sir, I saw your son whipping, and kicking, and knocking that good little pony about shamefully because he would not leap a gate that was too high for him.
Indignation that a mere black should laugh at him mastered Jerry, and the next moment his puppy teeth, sharp-pointed as needles, had scored the astonished black's naked calf in long parallel scratches from each of which leaped the instant blood.
She sniffed noses with him, and even condescended to leap about and frisk and play with him in quite puppyish fashion.
Buck did not know of this, and as he rounded the bend, the frost wraith of a rabbit still flitting before him, he saw another and larger frost wraith leap from the overhanging bank into the immediate path of the rabbit.
To leap to his rescue would mean death for Akut, too; but the brave old ape never hesitated.
Dragging the rope behind him, with no thought of escape, but in the hope that he would get at his tormentors, he leaped into the rear passage that ran behind the circle of permanent cages.
Mowgli trotted along under the trees, judging distances between branch and branch, occasionally climbing up a trunk and taking a trial leap from one tree to another till he came to the open ground, which he studied very carefully for an hour.
Then, without waiting to learn the effect of my throw, I wheeled, ran the few steps to the edge, and leaped as far out over that frightful chasm as I could.
And a doe leaped up, and a doe leaped up From the pond in the wood where the wild deer sup.