The reason for cryptography is to securely send messages and to make sure the message sent is what the receiver is getting using math and technology combined. It can involve encrypting plaintext into ciphertext and sending it and then the receiver decrypts the item. The main concerns of cryptography include integrity, confidentiality, and authentication. Due to this action one can ensure the person receiving the message gets it accurately as the sender intended. It can be sent over public key and the person opening the item has the private key. Digital signatures will show if the message has been tampered with and show who has opened it if added to the protocols of the encryption.
The goal most focused on when using this system is confidentiality as the meaning of the message is the main reason for it being sent and now wanting others to see. An example of this could range from ATMs to Bitcoin or other cryptocurrencies used.
However, if there are adjustments to the cyphertext it will modify the text underneath. These causing vulnerabilities and while hackers may not be able to decode the message, they will be able to change it without decrypting it. By changing the cyphertext, it will change the plain text underneath. The best ways to keep this service confidential is to be up to date on system updates and security patches. You can also use resistant algorithms to protect from attacks. Overall, using the right measures of protection, keeping what is meant to be confidential hidden when not sent, and keeping all protocols up to date, this type of algorithm can be very useful and efficient without worrying something will happen.
Resources:
University of Missouri-St. Louis. (n.d.). Cryptography. https://www.umsl.edu/~siegelj/information_theory/projects/des.netau.net/Cryptography%20and%20goals.html