R presents two layer securities, which includes both transposition and substitution cipher
Then the items in the database are encrypted with a substitution cipher
text after the insertion of fictitious transactions into the cipher text.
Clelland  used a substitution cipher
to encode characters to DNA strands.
If you and a friend want to exchange coded messages, you could send a backwards message or use a rail fence cipher or a substitution cipher
have used a substitution cipher
for plaintext encoding where base triplet is assigned to each letter of the alphabet, numeral and special characters and demonstrated a steganographic approach by hiding secret messages encoded as DNA strands among multitude of random DNA .
The main idea is that the plain text is encrypted with a substitution cipher
using a secret random key.
Our students enjoyed trying to solve a simple substitution cipher
using frequency tables.
About 2,000 years ago, transposition ciphers had made the barest appearance and Julius Caesar carried on correspondence in a very simple substitution cipher
This third programme, Le Chiffre Indechiffrable, traces the search for a new system of encryption, following the cracking of the mono-alphabetic substitution cipher
Criminals typically use homemade, simple substitution cipher
systems which use a single cipher text character to replace a plain text character.
In a substitution cipher
, the letters of the plaintext are replaced by other letters, symbols, or numbers (e.
It's probably some kind of letter substitution cipher