It is an extension of NIST publication 800-38G, FPE FF1 block cipher algorithms.
The traditional encryption methods produces an encrypted text which does not follow the format of the original plain text. For example, encrypting a phone number will produce an alpha numeric string which does not look like a phone number. On the other hand, when a phone number is encrypted using Semantic Encryption it produces an output that looks like a phone number, with NPA NXX XXXX arranged in the same format as the original plain text.
Unencrypted Phone Number : 770-098-0987
Encrypted Phone Number (Standard Encryption) : 1CYR+88ZGE1ymsx+o4x7uX3ekgDfnU11
Encrypted Phone Number (Semantic Encryption) : 767-208-7386
How Semantic Encryption differs from Standard Encryption?