Ancient Indian Cryptography
What is Cryptography:
Cryptography provides a method for secure communication. It stops unauthorized parties, commonly referred to as adversaries or hackers, from gaining access to the secret messages communicated between authorized parties. The method that cryptography provides is called encryption.
Encryption transforms a key and input, the plaintext, into an encrypted output, the ciphertext. Encryption algorithms are only considered secure if attackers cannot determine any properties of the plaintext or the key when presented with only the ciphertext. An attacker should not be able to find out anything about a key, even if they have many plaintext/ciphertext combinations that use that key.
A real-world example would be credit card information that you use for purchases on Amazon or other e-commerce sites. The code in your web browser encrypts the plaintext, your card number, into ciphertext, which to someone without the keys would look like illegible, random text. However, once your card number reaches its intended recipient, the online store, their software would decrypt it back into plaintext so they can charge you for your purchase.
Indian History about Cryptography:
A1967 book by David Kahn about the history of cryptography, the reference to Mlecchita Vikalpa in Kamasutra is cited as proof of the prevalence of cryptographic methods in ancient India. Though Kamasutra does not have details of the methods by which people of that time practiced this particular form of art, later commentators of Kamasutra have described several methods. For example, Yasodhara in his Jayamangala commentary on Kamasutra gives descriptions of methods known by the names Kautilya and Muladeviya. The ciphers described in the Jayamangala commentary are substitution ciphers: in Kautiliyam the letter substitutions are based on phonetic relations, and Muladeviya is a simplified version of Kautiliyam. There are also references to other methods for secret communications like Gudhayojya, Gudhapada and Gudhavarna. Some modern writers on cryptography have christened the ciphers alluded to in the Kamasutra as Kamasutra cipher or Vatsyayana cipher.
The exact date of the composition of Kamasutra has not been fixed. It is supposed that Vatsyayana must have lived between the first and sixth centuries AD. However, the date of the Jayamangla commentary has been fixed as between the tenth and thirteenth centuries CE.
The Indus writing system was NOT intended to be a secretive communication system, but could be decrypted and realized by anyone knowing the key. The key is simple: Meluhha language words which are denoted by the pictures (hieroglyphs) and similar-sounding words signifying metalwork by Meluhha artisans.
An authorized person who could unravel the communicated message was one with the knowledge of Meluhha (mleccha) language words for the picture and for items of metalwork.
Such persons were Bharatam Janam mentioned by Visvamitra in Rigveda. Bharatam Janam means ‘metalcaster folk’. They were referred to as Meluhha in cuneiform texts.
The earliest evidence of cipher-writing in human history is recorded on a potsherd discovered (dated ca. 3300 BCE) in Harappa by HARP (Harvard Archaeology Research Project) inscribed with a hieroglyph.
The underlying language used was Meluhha and pre-dated the invention of alphabetic or syllabic writing systems and later-day developments in encryption methods (for converting plain texts into cipher texts), cryptography and cryptology, apart from secret military messaging systems.
Five-petalled flower is tagaraka ‘tabernae montana’. Rebus: tagara ‘tin (metal)’. A hieroglyph signifying this flower is repeated thrice: Hieroglyph: kolmo ‘three’ rebus: kolami ‘smithy, forge’.
The cipher is simple engineering and dramatic. What is consigned in the pot on which the inscription was inscribed was NOT tagaraka, ‘fragrant flower used as a fragrance oil for the hair’ but a metal which was signified by a similar sounding word: tagara in Meluhha language.
The cipher writing system of ancient India was called mlecchita vikalpa because of the following meanings associated with the two words of the phrase:
The phrase mlecchita vikalpa is used by Vātstyāyana in reference to cipher writing of or by mleccha.
Thus, the tin metal referred to in parole, vaak, vernacular speech as tagara was denoted by a similar sounding word tagaraka. To signify this latter word, a picture of the tagaraka flower with 5 petals was used. Thus, there was a layered rebus-metonymy constituting the cipher. Rebus was deployed by use of picture-writing, i.e. use of pictures to denote the underlying spoken word. Metonymy layer was deployed to refer to metalwork denoted by similar sounding word. A writing system was born to support trade of metalwork by seafaring merchants, across linguistic areas.
Same rebus-metonymy layer applies to another hieroglyph — ‘rim of jar’:
On this Daimabad seal, the ‘rim of jar’ is signified.
In Meluhha language, the word was karNika ‘rim of jar’. Rebus-metonymy layer yields a similar sounding word karNI ‘supercargo’ of a seafaring merchant. Almost all inscriptions in Indus Script Corpora are metalwork catalogs and when this hierolyph of ‘rim of jar’ is used in a major segment of the inscriptions, the message is that the supercargo consignments of metalwork are signified by the message which is a ‘written’ record of such consignments transmitted through seafaring Meluhha merchants.
When this hieroglyph appears, the intent is NOT to record a consignment of pottery of rimmed jars, but to record the message that the consignment is of metalwork supercargo. Thus, together with rebus method (similar sounding words), metonymy is used which is the substitution of the name of an attribute or adjunct for that of the thing meant. The thing meant is NOT pottery but consignment of supercargo of metalwork, karNI.
A comparable rebus-metonymy cipher using Egyptian language is shown on Narmer palette. The syllables Nar and Mer in the name are rendered rebus by the hieroglyphs of ‘cuttle fish’ and ‘awl’ to signify words N’r and M’r respectively, which syllables are read together as Narmer. A writing system comparable to Indus Script is witnessed in Egypt.
Cryptology is a very young science. Although humans have had rudimentary forms of cryptography for thousands of years, the systematic study of cryptology as a science only began about a hundred years ago. The advent of computers made cryptography many orders of magnitude more complex than it had been previously.