What is Secret Sharing?
Secret sharing is like that:
Divide one file into several files.
If you divide the divided file by the specified number, you can restore it to the original file.
For example, with (2, 3) 3 share 2 combine, it is as following:
share source
share piece 1
combine
combine
share piece 2
share piece 3
share piece A
share piece B
share source
This will be something like that:
Divide one file into three files.
Arrange any two of the three files and apply "combine" to return to the original file.
For example, it might be something like
“Transfer the treasure map to a transparent sheet."
By overlaying transparent sheets for a specified number,you can see the treasure map.
The mechanism is something like this.
In the case of the (2, 3) 3 share 2 combine above:
Transfer the treasure map onto three transparent sheets.
By overlaying any two of the three transparent sheets, you can see the treasure map.
it is like this.
In this example, the share piece used for combining may be either 1, 2 or 3.
However, it is no good that "the same thing is two".
There is no such thing as the order, so in this case, it is to return in these three ways:
In that case, you can not combine.
It can not be joined unless it is a separate dispersion piece.
In general, cipher uses an encryption key (decryption key), but secret sharing does not use a key.
However, if you use secret sharing (software) which use secret sharing and cipher using a key together, in this case, a cipher key is used.
But, secret sharing itself does not use encryption keys (decryption keys) at all.
So to speak, the individual share pieces generated by sharing become like cipher text and decryption key.
The share by (2, 3) 3 share 2 combine is, for example, as follows.
Hello_Secret_Share_1st.sss
Hello_Secret_Share_2nd.sss
Hello_Secret_Share_3rd.sss
it can not be restored unless one can arrange two of the three share pieces. 
Each of the three share pieces only has some data of the source data.
The source data information can not be obtained by performing any operation on each share piece.
Shamia's secret sharing scheme is something like such things;
Each share piece is like a series of coefficients of simultaneous equations.
Unless this is done, any information about the source data will not get .
… Make (Convert) data into simultaneous equations.
… Solve simultaneous equations and return to data.
combine
Arrange the number of simultaneous equations (share pieces) necessary to solve the simultaneous equations, and solve the simultaneous equations back to the original data.
combine
Only you can arrange as many pieces of share as you need for combine.
Secret sharing conceals an information by this.
In ordinary cipher, it needs "You must remember the encryption key (password)."
The number of share pieces required for combining can not be arranged by others.
As long as this is true, secret sharing is secure.
On the other hand, on secret sharing, it needs remembering that
“Which piece of share and which piece of share can be combined?”
And you have to manage each share piece not to lose it, not to break it.
This is, in a sense, more cumbersome than ordinary cipher.
However, if  only you can arrange the necessary number of share pieces for combine, then no matter what operation is applied to the individual share pieces,the contents of the share source is never known.
This "robustness to analysis" is the main gain of using secret sharing.