{"id":49487,"date":"2026-04-02T10:14:25","date_gmt":"2026-04-02T08:14:25","guid":{"rendered":"https:\/\/www.investglass.com\/?p=49487"},"modified":"2026-04-15T11:53:03","modified_gmt":"2026-04-15T09:53:03","slug":"aes-cryptosystem","status":"publish","type":"post","link":"https:\/\/www.investglass.com\/tr\/aes-cryptosystem\/","title":{"rendered":"AES Kriptosistemi Nedir ve Nas\u0131l \u00c7al\u0131\u015f\u0131r?"},"content":{"rendered":"

AES kriptosistemi, modern veri koruman\u0131n merkezinde yer almaktad\u0131r. Zira bankalar<\/a>, varl\u0131k y\u00f6neticileri, sigortac\u0131lar ve hassas verilerle u\u011fra\u015fan kamu sekt\u00f6r\u00fc kurulu\u015flar\u0131 i\u00e7in AES'i anlamak iste\u011fe ba\u011fl\u0131 de\u011fildir. Finansal verilerin korunmas\u0131, d\u00fczenleyici gerekliliklerin kar\u015f\u0131lanmas\u0131 ve m\u00fc\u015fteri g\u00fcveninin s\u00fcrd\u00fcr\u00fclmesi i\u00e7in temeldir. AES kripto sistemi, sa\u011flam kriptografik \u00f6zellikler arac\u0131l\u0131\u011f\u0131yla gizlili\u011fi ve b\u00fct\u00fcnl\u00fc\u011f\u00fc sa\u011flayarak modern kurulu\u015flarda hassas verilerin g\u00fcvenli\u011fini sa\u011flamak i\u00e7in_essentialdir.<\/p>\n\n\n\n

Bu k\u0131lavuz, geli\u015fmi\u015f \u015fifreleme standard\u0131n\u0131n nas\u0131l \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131, simetrik \u015fifreleme i\u00e7in neden k\u00fcresel \u00f6l\u00e7\u00fct olmaya devam etti\u011fini ve InvestGlass gibi platformlar\u0131n nas\u0131l AES kulland\u0131\u011f\u0131n\u0131 anlatmaktad\u0131r. egemen<\/a> \u0130svi\u00e7re ve \u015firket i\u00e7i altyap\u0131daki m\u00fc\u015fteri verileri.<\/p>\n\n\n\n

AES Kriptosistemine Giri\u015f<\/h2>\n\n\n\n

Geli\u015fmi\u015f \u015eifreleme Standard\u0131 (AES), Ulusal Standartlar ve Teknoloji Enstit\u00fcs\u00fc (NIST) taraf\u0131ndan 2001 y\u0131l\u0131nda Federal Bilgi \u0130\u015flem Standard\u0131 (FIPS) 197 arac\u0131l\u0131\u011f\u0131yla standartla\u015ft\u0131r\u0131lm\u0131\u015f simetrik bir blok \u015fifrelemedir. G\u00fcn\u00fcm\u00fczdeki bilgisayar g\u00fcc\u00fcyle kaba kuvvet sald\u0131r\u0131lar\u0131na kar\u015f\u0131 savunmas\u0131z hale gelen eski Veri \u015eifreleme Standard\u0131'n\u0131n (DES) yerini almas\u0131 i\u00e7in \u00f6zel olarak tasarlanm\u0131\u015ft\u0131r.<\/p>\n\n\n\n

AES, 128 bit sabit blok boyutuyla \u00e7al\u0131\u015f\u0131r ve 128, 192 veya 256 bit anahtar uzunluklar\u0131n\u0131 destekler. Bu \u015fifreleme, s\u0131ras\u0131yla 10, 12 veya 14 d\u00f6n\u00fc\u015f\u00fcm turu ger\u00e7ekle\u015ftirerek t\u00fcm b\u00fcy\u00fck sekt\u00f6rlerde hassas verilerin korunmas\u0131 i\u00e7in sa\u011flam bir g\u00fcvenlik sa\u011flar.<\/p>\n\n\n\n

\u0130\u00e7in fi\u0307nansal kurumlar<\/a>, AES algoritmas\u0131 teknik bir standard\u0131n \u00f6tesini temsil eder. Finansal i\u015flemleri, m\u00fc\u015fteri kay\u0131tlar\u0131n\u0131 ve d\u00fczenleyici ba\u015fvurular\u0131 g\u00fcvence alt\u0131na alan \u015fifreleme s\u00fcrecinin temelini olu\u015fturur. ABD Ulusal G\u00fcvenlik Ajans\u0131, AES'yi gizli bilgileri korumak i\u00e7in onaylam\u0131\u015ft\u0131r; AES-128 G\u0130ZL\u0130 d\u00fczeydeki veriler i\u00e7in yeterliyken, AES-256 \u00c7OK G\u0130ZL\u0130 s\u0131n\u0131fland\u0131rmas\u0131 i\u00e7in gereklidir.<\/p>\n\n\n\n

InvestGlass, \u0130svi\u00e7re'de bar\u0131nd\u0131r\u0131lan ve \u015firket i\u00e7i da\u011f\u0131t\u0131mlar\u0131nda egemen m\u00fc\u015fteri verilerini korumak i\u00e7in AES tabanl\u0131 \u015fifrelemeye g\u00fcvenmektedir. Bu yakla\u015f\u0131m, bankalar\u0131n, varl\u0131k y\u00f6neticilerinin ve kamu sekt\u00f6r\u00fc kurulu\u015flar\u0131n\u0131n Amerikan veya \u00c7in bulut platformlar\u0131na ba\u011f\u0131ml\u0131 olmadan verileri g\u00fcvence alt\u0131na alabilmesini sa\u011flar.<\/p>\n\n\n\n

AES, \u015fifreleme ve \u015fifre \u00e7\u00f6zme i\u00e7in ayn\u0131 anahtar\u0131 kullanan simetrik bir \u015fifreleme algoritmas\u0131d\u0131r. Buna kar\u015f\u0131l\u0131k, RSA gibi asimetrik \u015fifreleme y\u00f6ntemleri, g\u00fcvenli anahtar de\u011fi\u015fimi ve ileti\u015fim protokolleri i\u00e7in yayg\u0131n olarak kullan\u0131lan bir a\u00e7\u0131k-\u00f6zel anahtar \u00e7ifti kullan\u0131r.<\/p>\n\n\n\n

\"Kripto
Kripto G\u00f6zetimi ve D\u00fczenlemesi<\/figcaption><\/figure>\n\n\n\n

Tarihsel Arka Plan ve Standardizasyon<\/h2>\n\n\n\n

NIST taraf\u0131ndan 1977'de standartla\u015ft\u0131r\u0131lan orijinal Veri \u015eifreleme Standard\u0131, temel bir zay\u0131fl\u0131ktan muzdaripti. 56 bit anahtar uzunlu\u011fu, 1990'lar\u0131n sonlar\u0131na do\u011fru pratikte k\u0131r\u0131labilir hale geldi. 1998'de Electronic Frontier Foundation, yakla\u015f\u0131k 250.000 ABD Dolar\u0131 maliyetli bir donan\u0131m kullanarak DES \u015fifresini sadece 56 saatte k\u0131ran DES Cracker adl\u0131 \u00f6zel bir makine \u00fcretti.<\/p>\n\n\n\n

Bu g\u00f6sterim, daha g\u00fc\u00e7l\u00fc bir halefin gerekli oldu\u011funu a\u00e7\u0131k\u00e7a ortaya koydu. 1997'de NIST, zorunlu 128 bit blok boyutuna ve 128, 192 ve 256 bit anahtarlar i\u00e7in deste\u011fe sahip algoritmalar talep eden halka a\u00e7\u0131k bir yar\u0131\u015fma ba\u015flatt\u0131. D\u00fcnya \u00e7ap\u0131ndaki kriptograflardan on be\u015f aday sunuldu.<\/p>\n\n\n\n

\u00dc\u00e7 y\u0131l boyunca on iki uluslararas\u0131 ekip taraf\u0131ndan yap\u0131lan titiz bir de\u011ferlendirmenin ard\u0131ndan NIST, alan\u0131 be\u015f finalistle s\u0131n\u0131rlad\u0131: Rijndael, Serpent, RC6, Twofish ve MARS. Ekim 2000'de Rijndael se\u00e7ildi. Bel\u00e7ikal\u0131 kriptograflar Joan Daemen ve Vincent Rijmen taraf\u0131ndan olu\u015fturulan Rijndael algoritmas\u0131, diferansiyel kriptanaliz ve lineer kriptanalize kar\u015f\u0131 m\u00fckemmel bir g\u00fcvenlik dengesi, DES'ten be\u015f kata kadar daha h\u0131zl\u0131 yaz\u0131l\u0131m h\u0131z\u0131 ve kompakt bir donan\u0131m ayak izi sundu.<\/p>\n\n\n\n

FIPS 197, 26 Kas\u0131m 2001'de yay\u0131nlanarak AES'i resmi olarak sabit 128 bit bloklarla tan\u0131mlad\u0131. 2004 y\u0131l\u0131na gelindi\u011finde ABD federal sistemleri AES kullan\u0131m\u0131n\u0131 zorunlu k\u0131ld\u0131 ve \u015fifreleme standard\u0131 ISO\/IEC 18033-3:2010 ve di\u011fer uluslararas\u0131 \u00e7er\u00e7evelere entegre edildi. 168 bit anahtarlar kullanan bir \u00e7\u00f6z\u00fcm olan Triple DES, 2000'lerin ortalar\u0131nda eskimi\u015f hale geldi.<\/p>\n\n\n\n

AES \u015eifreleme Algoritmas\u0131n\u0131n Temel Yap\u0131s\u0131<\/h2>\n\n\n\n

AES, durum olarak bilinen d\u00f6rt \u00e7arp\u0131 d\u00f6rt baytl\u0131k bir veri matrisi \u00fczerinde bir ikame perm\u00fctasyon a\u011f\u0131 olarak \u00e7al\u0131\u015f\u0131r. Bu durum, her bayt\u0131n sonlu alan GF(2^8) i\u00e7inde bir \u00f6\u011fe olarak ele al\u0131nd\u0131\u011f\u0131 128 bitlik bir veri blo\u011funu temsil eder.<\/p>\n\n\n\n

\u015eifre, anahtar uzunlu\u011fundan ba\u011f\u0131ms\u0131z olarak her zaman sabit 128 bit bloklar\u0131 i\u015fler. Tur say\u0131s\u0131 anahtar boyutuna ba\u011fl\u0131d\u0131r:<\/p>\n\n\n\n

Anahtar Uzunlu\u011fu<\/p><\/th>

Tur Say\u0131s\u0131<\/p><\/th>

Yayg\u0131n Ad<\/p><\/th><\/tr>

128 bit<\/p><\/td>

10 raunt<\/p><\/td>

AES-128<\/p><\/td><\/tr>

192 bit<\/p><\/td>

12 raunt<\/p><\/td>

AES-192<\/p><\/td><\/tr>

256 bit<\/p><\/td>

14 tur<\/p><\/td>

AES-256<\/p><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Her tur, kafa kar\u0131\u015f\u0131kl\u0131\u011f\u0131 ve yay\u0131lma sa\u011flamak i\u00e7in d\u00f6rt ana d\u00f6n\u00fc\u015f\u00fcm uygular: AltBaytlar (do\u011frusal olmayan bayt ikamesi), Sat\u0131rKayd\u0131r (d\u00f6ng\u00fcsel sat\u0131r kayd\u0131rma), S\u00fctunKar\u0131\u015ft\u0131r (s\u00fctun kar\u0131\u015ft\u0131rma) ve TurAnahtarEkle (tur anahtar\u0131 ile bit d\u00fczeyinde XOR i\u015flemi). Her turda kullan\u0131lan tur anahtarlar\u0131, anahtar \u00e7izelgesi algoritmas\u0131 kullan\u0131larak orijinal \u015fifreleme anahtar\u0131ndan birden \u00e7ok tur anahtar\u0131 t\u00fcreten anahtar geni\u015fletme ad\u0131 verilen bir i\u015flemle olu\u015fturulur. Son turda S\u00fctunKar\u0131\u015ft\u0131r atlan\u0131r.<\/p>\n\n\n\n

AES, hem genel ama\u00e7l\u0131 CPU'lar hem de \u00f6zel donan\u0131mlar \u00fczerinde verimli bir \u015fekilde \u00e7al\u0131\u015f\u0131r. Intel ve AMD'nin modern i\u015flemcileri, blok ba\u015f\u0131na yakla\u015f\u0131k on d\u00f6ng\u00fcde tam turlar\u0131 hesaplayan AES-NI komutlar\u0131n\u0131 i\u00e7erir, bu da ger\u00e7ek zamanl\u0131 finansal i\u015flemler ve disk \u015fifreleme i\u00e7in uygun veri ak\u0131\u015f h\u0131zlar\u0131 sa\u011flar.<\/p>\n\n\n\n

Y\u00fcksek Seviye \u015eifreleme ve \u015eifre \u00c7\u00f6zme S\u00fcreci<\/h3>\n\n\n\n

\u015eifreleme s\u00fcreci, ba\u015flang\u0131\u00e7ta bir AddRoundKey ad\u0131m\u0131yla ba\u015flar. D\u00fcz metin durumu, ilk tur anahtar\u0131yla birle\u015ftirilir. Bu ilk tur anahtar\u0131, orijinal \u015fifreleme anahtar\u0131ndan t\u00fcretilmi\u015ftir ve bit d\u00fczeyinde bir XOR i\u015flemi kullan\u0131larak ger\u00e7ekle\u015ftirilir.<\/p>\n\n\n\n

Toplam tur say\u0131s\u0131 Nr olmak \u00fczere, birinci turdan Nr-1. tura kadar her turda \u015fu i\u015flemler yap\u0131l\u0131r:<\/p>\n\n\n\n

    \n
  1. SubBytes, do\u011frusal olmayan bir S kutusu arama tablosu kullanarak her ilgili bayt\u0131 de\u011fi\u015ftirir<\/li>\n\n\n\n
  2. ShiftRows, ikinci sat\u0131r\u0131 bir pozisyon, \u00fc\u00e7\u00fcnc\u00fc sat\u0131r\u0131 iki pozisyon ve d\u00f6rd\u00fcnc\u00fc sat\u0131r\u0131 \u00fc\u00e7 pozisyon d\u00f6ng\u00fcsel olarak kayd\u0131r\u0131r<\/li>\n\n\n\n
  3. MixColumns, her s\u00fctunu GF(2^8) i\u00e7inde sabit bir polinom ile \u00e7arpar<\/li>\n\n\n\n
  4. AddRoundKey, oturum anahtar\u0131yla durumu XOR'lar<\/li>\n<\/ol>\n\n\n\n

    Son turda MixColumns i\u015flemi atlan\u0131r ve ShiftRows'tan do\u011frudan AddRoundKey'e ge\u00e7ilir. Bu tasar\u0131m tercihi, baz\u0131 uygulama optimizasyonlar\u0131n\u0131 basitle\u015ftirir.<\/p>\n\n\n\n

    \u015eifre \u00e7\u00f6zme i\u015flemi, ters i\u015flemleri ters s\u0131rada uygular. Son tur anahtar\u0131yla AddRoundKey ile ba\u015flayarak, her tur InvShiftRows, InvSubBytes, InvMixColumns ve AddRoundKey i\u015flemlerini ger\u00e7ekle\u015ftirir. Hem \u015fifreleme hem de \u015fifre \u00e7\u00f6zme, ayn\u0131 d\u00f6rt \u00e7arp\u0131 d\u00f6rt durumu \u00fczerinde \u00e7al\u0131\u015farak ancak ters d\u00f6n\u00fc\u015f\u00fcmlerle ayn\u0131 genel yap\u0131y\u0131 korur. AES kriptosisteminin karma\u015f\u0131kl\u0131\u011f\u0131 ve geni\u015f anahtar alan\u0131 nedeniyle, sald\u0131rganlar\u0131n do\u011fru anahtar olmadan verileri \u015fifrelemesi hesaplama a\u00e7\u0131s\u0131ndan m\u00fcmk\u00fcn de\u011fildir.<\/p>\n\n\n\n

    Anahtar Program\u0131 ve Yuvarlak Anahtar \u00dcretimi<\/h3>\n\n\n\n

    Anahtar \u00e7izelgesi algoritmas\u0131, her \u015fifre turu i\u00e7in orijinal gizli anahtar\u0131 bir dizi tur anahtar\u0131na geni\u015fletir, ayr\u0131ca ilk anahtar eklemesi de yap\u0131l\u0131r. AES-128 i\u00e7in bu, 44 adet d\u00f6rt baytl\u0131k kelime (her biri 128 bitlik 11 tur anahtar\u0131) \u00fcretir.<\/p>\n\n\n\n

    Plan, anahtar turlar\u0131 aras\u0131ndaki basit ili\u015fkileri \u00f6nlemek i\u00e7in birka\u00e7 i\u015flemi birle\u015ftirir:<\/p>\n\n\n\n