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"Lenah H. Sutcliffe Higbee (May 18, 1874 – January 10, 1941) was a pioneering Canadian-born United States Navy military nurse, who served as Superintendent of the U.S. Navy Nurse Corps during World War I. She is best known for being the first female recipient of the Navy Cross. Early life and education Higbee was born Lenah H. Sutcliffe in Chatham, New Brunswick, Canada, on 18 May 1874. She completed nurses' training at the New York Post-Graduate Hospital in 1899 and entered private practice soon thereafter. Lenah Higbee took postgraduate training at Fordham Hospital, New York in 1908. Career In October 1908, she joined the newly established U.S. Navy Nurse Corps as one of its first twenty members. These nurses, who came to be called "The Sacred Twenty", were the first women to formally serve as members of the Navy. She was promoted to Chief Nurse in 1909. Lenah Higbee became Chief Nurse at Norfolk Naval Hospital in April 1909. In January 1911, Higbee became the second Superintendent of the U.S. Navy Nurse Corps. For her achievements in leading the Corps through the First World War, Chief Nurse Higbee was awarded the Navy Cross. She was the first woman to receive that decoration. =Navy Cross citation= Later life and death She resigned from the position of Superintendent and retired from the Navy on 23 November 1922. Higbee died at Winter Park, Florida, on 10 January 1941 and is buried at Arlington National Cemetery. Legacy The US Navy has named two ships in her honor; * , a commissioned in 1945, as the first U.S. Navy warship to bear the name of one of its female members. * , a planned guided missile destroyer scheduled to enter the fleet in 2024. References ;Further reading External links * Photos of Lenah Higbee * Nurses and the U.S. Navy --Overview and Special Image Selection Naval Historical Center * Arlington National Cemetery biography *Lenah Sutcliffe Higbee Naval History and Heritage Command 1874 births 1941 deaths American nursing administrators American military personnel of World War I American women in World War I Canadian emigrants to the United States Burials at Arlington National Cemetery Female nurses in World War I Recipients of the Navy Cross (United States) Female United States Navy officers United States Navy Nurse Corps officers "
"Vanellus is the genus of waders which provisionally contains all lapwings except red-kneed dotterel, Erythrogonys cinctus. The name "vanellus" is Latin for "little fan", vanellus being the diminutive of vannus ("winnowing fan"). The name is in reference to the sound lapwings' wings make in flight.Terres & NAS (1980): p.741 Description These long-legged waders mostly have strongly patterned plumage. Although the most familiar Eurasian lapwing, Vanellus vanellus (northern lapwing), has a wispy crest, only two other species do so. Red or yellow facial wattles are a more typical decoration. Only northern, sociable, white-tailed, grey-headed and brown-chested lapwings are truly migratory species. The Andean lapwing moves downhill in winter. Spur-winged, blacksmith, river, southern, Andean and pied lapwings are boldly patterned, red-eyed species with a spurred carpal (wrist) joint. Many species have wattles which can be small (black-headed, spot-breasted, red-wattled and banded lapwings) or large (white-crowned, African wattled, yellow-wattled, Javan, and masked lapwings). The latter species are the largest of the plover family, since several exceed . Systematics The genus Vanellus was erected by the French zoologist Mathurin Jacques Brisson in 1760. The name was derived by tautonymy from the original binomial name of the northern lapwing Tringa vanellus introduced by Linnaeus in 1758. Vanellus is the Medieval Latin for a "lapwing". It is a diminutive of the Latin vanus meaning "winnowing" or "fan". The systematics of Vanellus have hitherto resisted clear resolution. Essentially, no major revision can be brought to agree with another, and up to 19 genera were at one time recognized for the 24 lapwing species. While it might be desirable to split up this large and diverse genus a bit, the morphological characters are a confusing mix of apomorphic and plesiomorphic traits in any one species, with few relationships readily apparent. Molecular data has been found to provide even less sufficient resolution, though the lapwings have not yet been as thoroughly studied under this aspect as other Charadriiformes.Piersma & Wiersma (1996), Thomas et al. (2004) The only thing that can be said with a fair degree of certainty is that according to the DNA sequence data one group of 5 species seems to stand out. These are wattle-less lapwings which were separated as Anitibyx, Belonopterus, Hoplopterus (in the narrow sense) and Ptiloscelys. They are visually very dissimilar, but it is notable that their distribution forms a clean band through the tropical regions of the world except Australia; they might conceivably form a clade. The only species among them that is migratory is the Andean lapwing (V. resplendens), which as noted above cannot be allied with the truly migratory lapwings on these grounds. However, if these were to be split off, for one thing it is almost certain that other lineages would also require separation; the new genus' name would probably be Hoplopterus, which is the longest- and most widely used alternative lapwing genus. =List of species in taxonomic order= * Northern lapwing, also known as green plover and as peewit, Vanellus vanellus Alternatively placed in Hemiparra: * Long-toed lapwing, Vanellus crassirostris Alternatively placed in Anitibyx: * Blacksmith lapwing or blacksmith plover, Vanellus armatus Alternatively placed in Hoplopterus: * Spur-winged lapwing or "spur-winged plover", Vanellus spinosus * River lapwing or "spur-winged lapwing", Vanellus duvaucelii Alternatively placed in Sarciophorus, Lobivanellus or Hoplopterus: * Black-headed lapwing or black- headed plover, Vanellus tectus Alternatively placed in Lobipluvia or Hoplopterus: * Yellow-wattled lapwing, Vanellus malabaricus Alternatively placed in Xiphidiopterus or Hoplopterus: * White-crowned lapwing, white-headed lapwing, white-crowned plover or white-headed plover, Vanellus albiceps Alternatively placed in Stephanibyx or Hoplopterus: * Senegal lapwing or lesser black-winged lapwing, Vanellus lugubris * Black-winged lapwing or greater black-winged lapwing, Vanellus melanopterus Crowned lapwing in Tanzania * Crowned lapwing or crowned plover, Vanellus coronatus Alternatively placed in Afribyx: * African wattled lapwing or wattled lapwing, Vanellus senegallus Alternatively placed in Tylibyx, Lobivanellus or Hoplopterus: * Spot-breasted lapwing, Vanellus melanocephalus Alternatively placed in Anomalophrys: * Brown-chested lapwing, Vanellus superciliosus Alternatively placed in Microsarcops or Hoplopterus: * Grey-headed lapwing, Vanellus cinereus Alternatively placed in Lobivanellus or Hoplopterus: * Red-wattled lapwing, Vanellus indicus Alternatively placed in Rogibyx: * Javan lapwing, Javanese lapwing, or Javanese wattled lapwing, Vanellus macropterus Alternatively placed in Zonifer, Lobivanellus or Hoplopterus: * Banded lapwing, Vanellus tricolor Alternatively placed in Lobibyx, Lobivanellus or Hoplopterus: * Masked lapwing or "spur-winged plover", Vanellus miles Alternatively placed in Chettusia: * Sociable lapwing or sociable plover, Vanellus gregarius Alternatively placed in Vanellochettusia or Chettusia: * White-tailed lapwing or white-tailed plover, Vanellus leucurus Alternatively placed in Hoploxypterus: * Pied lapwing, Vanellus cayanus Alternatively placed in Belonopterus: * Southern lapwing, Vanellus chilensis Alternatively placed in Ptiloscelys or Belonopterus: * Andean lapwing, Vanellus resplendens Prehistoric species Species known only from fossil or subfossil remains include: * Vanellus madagascariensis (14th century Madagascar) * Vanellus lilloi (Middle/Late Pleistocene of Centinela del Mar, Argentina) * Vanellus downsi (Late Pleistocene of Rancho La Brea, USA) * Vanellus edmundi (Late Pleistocene of Talalra, Peru) The last three of these seem to be very closely related to the southern lapwing and all were placed in Belonopterus by the describing authors. If Viator picis, also from the Late Pleistocene of Talara, does not belong to an entirely extinct lineage, it might belong to that group too; it seems too large to be closely related to the smallish pied lapwing.Campbell (2002) Neither the Early Oligocene DolicopterusNot Dolichopterus, contra Mlíkovský (2002) from Ronzon, France nor the supposed mid-Oligocene lapwing "Vanellus" selysii of Rupelmonde (Belgium) unquestionably belong here. While their age suggests that they may indeed represent some ancient lapwings, the fossil remains have not been studied for many decades and a review is seriously overdue.Mlíkovský (2002) References Sources * Campbell, Kenneth E. Jr. (2002): A new species of Late Pleistocene lapwing from Rancho La Brea, California [English with Spanish abstract]. Condor 104: 170–174. HTML abstract and first page image * Mlíkovský, Jirí (2002): Cenozoic Birds of the World, Part 1: Europe. Ninox Press, Prague. PDF fulltext * Piersma, Theunis & Wiersma, Popko (1996): Family Charadriidae (Plovers). In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 3: Hoatzin to Auks): 384–443, plates 35–39. Lynx Edicions, Barcelona. * Further reading * Hayman, Peter; Marchant, John & Prater, Tony (1986): Shorebirds: an identification guide to the waders of the world. Houghton Mifflin, Boston. * Terres, John K. & National Audubon Society (1980): The Audubon Society Encyclopedia of North American Birds. Alfred A. Knopf, New York. External links Lapwing videos on the Internet Bird Collection Bird genera "
"In cryptography, padding is any of a number of distinct practices which all include adding data to the beginning, middle, or end of a message prior to encryption. In classical cryptography, padding may include adding nonsense phrases to a message to obscure the fact that many messages end in predictable ways, e.g. sincerely yours. Classical cryptography Official messages often start and end in predictable ways: My dear ambassador, Weather report, Sincerely yours, etc. The primary use of padding with classical ciphers is to prevent the cryptanalyst from using that predictability to find known plaintextGordon Welchman, The Hut Six Story: Breaking the Enigma Codes, p. 78. that aids in breaking the encryption. Random length padding also prevents an attacker from knowing the exact length of the plaintext message. A famous example of classical padding which caused a great misunderstanding is "the world wonders" incident, which nearly caused an Allied loss at the WWII Battle off Samar, part of the larger Battle of Leyte Gulf. In that example, Admiral Chester Nimitz, the Commander in Chief, U.S. Pacific Fleet in World War II, sent the following message to Admiral Bull Halsey, commander of Task Force Thirty Four (the main Allied fleet) at the Battle of Leyte Gulf, on October 25, 1944: With padding (bolded) and metadata added, the message became: Halsey's radio operator mistook some of the padding for the message, so Admiral Halsey ended up reading the following message: Admiral Halsey interpreted the padding phrase "the world wonders" as a sarcastic reprimand, causing him to have an emotional outburst and then lock himself in his bridge and sulk for an hour before moving his forces to assist at the Battle off Samar. Halsey's radio operator should have been tipped off by the letters RR that "the world wonders" was padding; all other radio operators who received Admiral Nimitz's message correctly removed both padding phrases. Many classical ciphers arrange the plaintext into particular patterns (e.g., squares, rectangles, etc.) and if the plaintext doesn't exactly fit, it is often necessary to supply additional letters to fill out the pattern. Using nonsense letters for this purpose has a side benefit of making some kinds of cryptanalysis more difficult. Symmetric cryptography =Hash functions= Most modern cryptographic hash functions process messages in fixed-length blocks; all but the earliest hash functions include some sort of padding scheme. It is critical for cryptographic hash functions to employ termination schemes that prevent a hash from being vulnerable to length extension attacks. Many padding schemes are based on appending predictable data to the final block. For example, the pad could be derived from the total length of the message. This kind of padding scheme is commonly applied to hash algorithms that use the Merkle–Damgård construction. =Block cipher mode of operation= Electronic codebook and cipher-block chaining (CBC) mode are examples of block cipher mode of operation. Block cipher modes for symmetric-key encryption algorithms require plain text input that is a multiple of the block size, so messages may have to be padded to bring them to this length. There is currently a shift to use streaming mode of operation instead of block mode of operation. An example of streaming mode encryption is the counter mode of operation.https://www.cs.columbia.edu/~smb/classes/s09/l05.pdf, pg 17 Streaming modes of operation can encrypt and decrypt messages of any size and therefore do not require padding. More intricate ways of ending a message such as ciphertext stealing or residual block termination avoid the need for padding. A disadvantage of padding is that it makes the plain text of the message susceptible to padding oracle attacks. Padding oracle attacks allow the attacker to gain knowledge of the plain text without attacking the block cipher primitive itself. Padding oracle attacks can be avoided by making sure that an attacker cannot gain knowledge about the removal of the padding bytes. This can be accomplished by verifying a message authentication code (MAC) or digital signature before removal of the padding bytes, or by switching to a streaming mode of operation. Bit padding Bit padding can be applied to messages of any size. A single set ('1') bit is added to the message and then as many reset ('0') bits as required (possibly none) are added. The number of reset ('0') bits added will depend on the block boundary to which the message needs to be extended. In bit terms this is "1000 ... 0000". This method can be used to pad messages which are any number of bits long, not necessarily a whole number of bytes long. For example, a message of 23 bits that is padded with 9 bits in order to fill a 32-bit block: ... 1011 1001 1101 0100 0010 0111 0000 0000 This padding is the first step of a two-step padding scheme used in many hash functions including MD5 and SHA. In this context, it is specified by RFC1321 step 3.1. This padding scheme is defined by ISO/IEC 9797-1 as Padding Method 2. Byte padding Byte padding can be applied to messages that can be encoded as an integral number of bytes. =ANSI X9.23= In ANSI X9.23, between 1 and 8 bytes are always added as padding. The block is padded with random bytes (although many implementations use 00) and the last byte of the block is set to the number of bytes added. Example: In the following example the block size is 8 bytes, and padding is required for 4 bytes (in hexadecimal format) ... 00 00 00 04 =ISO 10126= ISO 10126 (withdrawn, 2007ISO catalog, ISO 10126-1:1991ISO catalog, ISO 10126-2:1991) specifies that the padding should be done at the end of that last block with random bytes, and the padding boundary should be specified by the last byte. Example: In the following example the block size is 8 bytes and padding is required for 4 bytes ... 81 A6 23 04 =PKCS#5 and PKCS#7= PKCS#7 is described in RFC 5652. Padding is in whole bytes. The value of each added byte is the number of bytes that are added, i.e. bytes, each of value are added. The number of bytes added will depend on the block boundary to which the message needs to be extended. The padding will be one of: 01 02 02 03 03 03 04 04 04 04 05 05 05 05 05 06 06 06 06 06 06 etc. This padding method (as well as the previous two) is well-defined if and only if is less than 256. Example: In the following example the block size is 8 bytes and padding is required for 4 bytes ... 04 04 04 04 If the length of the original data is an integer multiple of the block size , then an extra block of bytes with value is added. This is necessary so the deciphering algorithm can determine with certainty whether the last byte of the last block is a pad byte indicating the number of padding bytes added or part of the plaintext message. Consider a plaintext message that is an integer multiple of bytes with the last byte of plaintext being 01. With no additional information, the deciphering algorithm will not be able to determine whether the last byte is a plaintext byte or a pad byte. However, by adding bytes each of value after the 01 plaintext byte, the deciphering algorithm can always treat the last byte as a pad byte and strip the appropriate number of pad bytes off the end of the ciphertext; said number of bytes to be stripped based on the value of the last byte. PKCS#5 padding is identical to PKCS#7 padding, except that it has only been defined for block ciphers that use a 64-bit (8-byte) block size. In practice the two can be used interchangeably. =ISO/IEC 7816-4= ISO/IEC 7816-4:2005ISO catalog, ISO/IEC 7816-4:2005 is identical to the bit padding scheme, applied to a plain text of N bytes. This means in practice that the first byte is a mandatory byte valued '80' (Hexadecimal) followed, if needed, by 0 to N − 1 bytes set to '00', until the end of the block is reached. ISO/IEC 7816-4 itself is a communication standard for smart cards containing a file system, and in itself does not contain any cryptographic specifications. Example: In the following example the block size is 8 bytes and padding is required for 4 bytes ... 80 00 00 00 The next example shows a padding of just one byte ... DD 80 Zero padding All the bytes that are required to be padded are padded with zero. The zero padding scheme has not been standardized for encryption, although it is specified for hashes and MACs as Padding Method 1 in ISO/IEC 10118-1ISO/IEC 10118-1:2000 Information technology – Security techniques – Hash-functions – Part 1: General and ISO/IEC 9797-1.ISO/IEC 9797-1:1999 Information technology – Security techniques – Message Authentication Codes (MACs) – Part 1: Mechanisms using a block cipher Example: In the following example the block size is 8 bytes and padding is required for 4 bytes ... 00 00 00 00 Zero padding may not be reversible if the original file ends with one or more zero bytes, making it impossible to distinguish between plaintext data bytes and padding bytes. It may be used when the length of the message can be derived out-of- band. It is often applied to binary encoded strings (null-terminated string) as the null character can usually be stripped off as whitespace. Zero padding is sometimes also referred to as "null padding" or "zero byte padding". Some implementations may add an additional block of zero bytes if the plaintext is already divisible by the block size. Public key cryptography In public key cryptography, padding is the process of preparing a message for encryption or signing using a specification or scheme such as PKCS#1 v1.5, OAEP, PSS, PSSR, IEEE P1363 EMSA2 and EMSA5. A modern form of padding for asymmetric primitives is OAEP applied to the RSA algorithm, when it is used to encrypt a limited number of bytes. The operation is referred to as "padding" because originally, random material was simply appended to the message to make it long enough for the primitive. This form of padding is not secure and is therefore no longer applied. A modern padding scheme aims to ensure that the attacker cannot manipulate the plaintext to exploit the mathematical structure of the primitive and will usually be accompanied by a proof, often in the random oracle model, that breaking the padding scheme is as hard as solving the hard problem underlying the primitive. Traffic analysis and protection via padding Even if perfect cryptographic routines are used, the attacker can gain knowledge of the amount of traffic that was generated. The attacker might not know what Alice and Bob were talking about, but can know that they were talking and how much they talked. In some circumstances this leakage can be highly compromising. Consider for example when a military is organising a secret attack against another nation: it may suffice to alert the other nation for them to know merely that there is a lot of secret activity going on. As another example, when encrypting Voice Over IP streams that use variable bit rate encoding, the number of bits per unit of time is not obscured, and this can be exploited to guess spoken phrases. Similarly, the burst patterns that common video encoders produce are often sufficient to identify the streaming video a user is watching uniquely. Even the total size of an object alone, such as a website, file, software package download, or online video, can uniquely identify an object, if the attacker knows or can guess a known set the object comes from. The side-channel of encrypted content length was used to extract passwords from HTTPS communications in the well-known CRIME and BREACH attacks. Padding an encrypted message can make traffic analysis harder by obscuring the true length of its payload. The choice of length to pad a message to may be made either deterministically or randomly; each approach has strengths and weaknesses that apply in different contexts. =Randomized padding= A random number of additional padding bits or bytes may be appended to the end of a message, together with an indication at the end how much padding was added. If the amount of padding is chosen as a uniform random number between 0 and some maximum M, for example, then an eavesdropper will be unable to determine the message's length precisely within that range. If the maximum padding M is small compared to the message's total size, then this padding will not add much overhead, but the padding will obscure only the least-significant bits of the object's total length, leaving the approximate length of large objects readily observable and hence still potentially uniquely identifiable by their length. If the maximum padding M is comparable to the size of the payload, in contrast, an eavesdropper's uncertainty about the message's true payload size is much larger, at the cost that padding may add up to 100% overhead (2\times blow-up) to the message. In addition, in common scenarios in which an eavesdropper has the opportunity to see many successive messages from the same sender, and those messages are similar in ways the attacker knows or can guess, then the eavesdropper can use statistical techniques to decrease and eventually even eliminate the benefit of randomized padding. For example, suppose a user's application regularly sends messages of the same length, and the eavesdropper knows or can guess fact based on fingerprinting the user's application for example. Alternatively, an active attacker might be able to induce an endpoint to send messages regularly, such as if the victim is a public server. In such cases, the eavesdropper can simply compute the average over many observations to determine the length of the regular message's payload. =Deterministic padding= A deterministic padding scheme always pads a message payload of a given length to form an encrypted message of a particular corresponding output length. When many payload lengths map to the same padded output length, an eavesdropper cannot distinguish or learn any information about the payload's true length within one of these length buckets, even after many observations of the identical-length messages being transmitted. In this respect, deterministic padding schemes have the advantage of not leaking any additional information with each successive message of the same payload size. On the other hand, suppose an eavesdropper can benefit from learning about small variations in payload size, such as plus or minus just one byte in a password- guessing attack for example. If the message sender is unlucky enough to send many messages whose payload lengths vary by only one byte, and that length is exactly on the border between two of the deterministic padding classes, then these plus-or-minus one payload lengths will consistently yield different padded lengths as well (plus-or-minus one block for example), leaking exactly the fine-grained information the attacker desires. Against such risks, randomized padding can offer more protection by independently obscuring the least-significant bits of message lengths. Common deterministic padding methods include padding to a constant block size and padding to the next- larger power of two. Like randomized padding with a small maximum amount M, however, padding deterministically to a block size much smaller than the message payload obscures only the least-significant bits of the messages true length, leaving the messages's true approximate length largely unprotected. Padding messages to a power of two (or any other fixed base) reduces the maximum amount of information that the message can leak via its length from O() to O(\log ). Padding to a power of two increases message size overhead by up to 100%, however, and padding to powers of larger integer bases increase maximum overhead further. The PADMÉ scheme, proposed for padded uniform random blobs or PURBs, deterministically pads messages to lengths representable as a floating point number whose mantissa is no longer (i.e., contains no more significant bits) than its exponent. This length constraint ensures that a message leaks at most O(\log ) bits of information via its length, like padding to a power of two, but incurs much less overhead of at most 12% for tiny messages and decreasing gradually with message size. See also * Chaffing and winnowing, mixing in large amounts of nonsense before sending * Ciphertext stealing, another approach to deal with messages that are not a multiple of the block length * Initialization vector, salt (cryptography), which are sometimes confused with padding * Key encapsulation, an alternative to padding for public key systems used to exchange symmetric keys * PURB or padded uniform random blob, an encryption discipline that minimizes leakage from either metadata or length * Russian copulation, another technique to prevent cribs References Further reading * XCBC: csrc.nist.gov/groups/ST/toolkit/BCM/documents/workshop2/presentations/xcbc.pdf Cryptography Padding algorithms "