The [[Ancient Greece|Greeks of Classical times]] are said to have known of ciphers (e.g., the [[scytale]] transposition cipher claimed to have been used by the [[Sparta]]n military).<ref name="JrT6G">{{Cite book|first=V.V.|last=I︠A︡shchenko|title=Cryptography: an introduction|year=2002|url={{Google books|cH-NGrpcIMcC|page=6|plainurl=yes}}|publisher=AMS Bookstore|page=6|isbn=978-0-8218-2986-8}}</ref> [[Steganography]] (i.e., hiding even the existence of a message so as to keep it confidential) was also first developed in ancient times. An early example, from [[Herodotus]], was a message tattooed on a slave's shaved head and concealed under the regrown hair.<ref name="kahnbook">{{Cite book|last=Kahn|first=David|author-link=David Kahn (writer)|title=The Codebreakers|year=1967|isbn=978-0-684-83130-5|title-link=The Codebreakers}}</ref> Other steganography methods involve 'hiding in plain sight,' such as using a [[music cipher#Musical Steganography|music cipher]] to disguise an encrypted message within a regular piece of sheet music. More modern examples of steganography include the use of [[invisible ink]], [[microdot]]s, and [[digital watermark]]s to conceal information.

 

 

In [[Sassanid Persia]], there were two secret scripts, according to the Muslim author [[Ibn al-Nadim]]: the ''šāh-dabīrīya'' (literally "King's script") which was used for official correspondence, and the ''rāz-saharīya'' which was used to communicate secret messages with other countries.<ref name="VOLuq">{{cite web|url=http://www.iranicaonline.org/articles/codes-romuz-sg|title=CODES – Encyclopaedia Iranica|last=electricpulp.com|website=www.iranicaonline.org|access-date=4 March 2017|archive-date=5 March 2017|archive-url=https://web.archive.org/web/20170305113651/http://www.iranicaonline.org/articles/codes-romuz-sg|url-status=live}}</ref>