The process of decryption pertains to converting of encrypted data into its former state. Basically, it is the reverse process of encryption. What happens within the process is that the encrypted information is decoded in such a way that that an authorized user would be the only one to see the data as decryption requires a secret key. Decryption may either be done manually or automatically.
Within the process, the system extracts and transforms garbled data into words and images that can easily be understood not just by the reader, but also by the system.
Decryption requires the inverse of a matrix. However, the inverse of the matrix does not always exist. If it is not invertible, then the content cannot be decrypted.