Everyone can extract the information from audio file then how its called secure. Means if we hide the text message into an audio file its the possibility that the third person can extract then how its secure? What is the security over sharing internet using this technique? Anyone can explain?
Steganography is an Obfuscation technique. It doesn't offer any sort of confidentiality to the data unless an additional encryption is used. The above said is true irrespective of what kind of file you try to embed your data.
Secure usage of steganography is when you use encryption along with it. Suppose you are trying to hide message M in file F.
Step 1: Encrypt message M. C = E(M)
Step 2: Use the Least significant bit of each byte of the file F to store the following - C and Details of Encryption Algorithm