Shihāb al-Dīn Abū 'l-Abbās Aḥmad ibn ‘Alī ibn Aḥmad ‘Abd Allāhal-Fazārī al-Shāfiʿī^[1] better known by theepithetal-Qalqashandī (Arabic:شهاب الدين أحمد بن علي بن أحمد القلقشندي; 1355 or 1356 – 1418), was a medievalArabEgyptianencyclopedist,polymath andmathematician. A native of theNile Delta, he became a Scribe of the Scroll (Katib al-Darj), or clerk of theMamluk chancery inCairo,Egypt. Hismagnum opus is the voluminous administrative encyclopediaṢubḥ al-Aʿshá.

Ṣubḥ al-Aʿshá fī Ṣināʿat al-Inshāʾ ('The Dawn of the Blind' or 'Daybreak for the Night-Blind regarding the Composition of Chancery Documents'); a fourteen-volume encyclopedia completed in 1412, is an administrative manual on geography, political history, natural history, zoology, mineralogy, cosmography, and time measurement. Based on theMasālik al-abṣār fī mamālik al-amṣar ofShihab al-Umari,^[2] it has been called "one of the final expressions of the genre ofArabic administrative literature".^[3] Selections on "Seats of Government " and "Regulations of the Kingdom " from Early Islam to the Mamluks' have been published separately.^[4]

TheṢubḥ al-aʿshā was cited byDavid Kahn as the first published discussion of the substitution and transposition of ciphers, and the first description of apolyalphabetic cipher, in which eachplaintext letter is assigned more than one substitution. The exposition oncryptanalysis included the use of tables ofletter frequencies and sets of letters which cannot occur together in one word.^[5]Kahn therefore cited it as the first work in human history that described cryptology, because it described both cryptography and cryptanalysis. Al-Qalqashandi quoted the text relevant to cryptology from the work ofIbn al-Durayhim (1312–1361) that was once considered lost. Later discoveries in Istanbul‟s Sulaimaniyyah Ottoman Archives did not just find the work by Ibn Duraihim, but also works ofal-Kindi in the 9th century that is now considered the oldest work on cryptology.^[6]

• Bosworth, C. E. (1978)."al-Ḳalḳas̲h̲andī". Invan Donzel, E.;Lewis, B.;Pellat, Ch. &Bosworth, C. E. (eds.).The Encyclopaedia of Islam, Second Edition.Volume IV: Iran–Kha. Leiden: E. J. Brill. pp. 509–511.doi:10.1163/1573-3912_islam_SIM_3832.OCLC 758278456.

• Qalqashandī, Aḥmad ibn ʻAlī (1879).Die Geographie und Verwaltung von Ägypten. Translated byFerdinand Wüstenfeld. Dieterich.
• Qalqashandī, Aḥmad ibn ʻAlī (1903).Ṣuhḥ al-aishā. Vol. 1. Cairo.{{cite book}}: CS1 maint: location missing publisher (link)
• Qalqashandī, Aḥmad ibn ʻAlī (1913).Kitab subh al-a'shá. Vol. 1. Al-Qhirah al-Maba'ah al-Amryah.
• Qalqashandī, Aḥmad ibn ʻAlī (1913).Kitab subh al-a'shá. Vol. 6. Al-Qhirah al-Maba'ah al-Amryah.
• Damanhr, Amad ibn Abd al-Munim;Qalqashandī Aḥmad ibn ʻAlī; Ibn Jbir, Muammad ibn Amad, 1299-1378 (1871).Sabl al-rashd ilá naf' al-'ibd. Iskandariyah Al-Maba'ah al-Waaryah.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)

ArabicWikisource has original text related to this article:

Ahmad al-Qalqashandi

• Christian and Jewish Religious Dignitaries in Mamluk Egypt and Syria: Qalqashandi's Information on their Hierarchy, Titulature, and Appointment (I &II)International Journal of Middle East Studies, 3:1, 3:2 (1972)

• 1350s births
• 1418 deaths
• 14th-century Arab people
• 15th-century Arab people
• 14th-century Egyptian people
• 14th-century mathematicians
• 15th-century Egyptian people
• 15th-century mathematicians
• Egyptian encyclopedists
• Egyptian scientists
• Medieval Egyptian mathematicians
• Scholars from the Mamluk Sultanate
• Encyclopedists of the medieval Islamic world
• Medieval cryptographers
• Egyptian cryptographers
• Ghatafan

• Articles with short description
• Short description matches Wikidata
• Articles with hCards
• Articles containing Arabic-language text
• CS1 maint: location missing publisher
• CS1 maint: multiple names: authors list
• CS1 maint: numeric names: authors list