By encrypting personal information, cryptography can protect your privacy. It prevents unwanted snooping into things you want kept private. When used by others, it can protect whatever information you may have given them. It helps keeps what you want private, private.

You can use cryptography to protect your communications. By encrypting voice and/or data communications, you can protect yourself against evesdroppers and snoops.

You can use cryptography to protect your property. Information is property and can have value. That value may depend on it not being compromised. However, information is readily copied and transmitted. By encrypting that information, that property, you protect it from being compromised when it is copied and transmitted. The value is preserved by preventing unwanted people from being able to use it. You preserve its value to you and remove its value to them.

You can use cryptography to protect your systems. By encrypting passwords, access information, and communications, you make it harder for an intruder to compromise your system.

Cryptography can be used to authenticate. By using cryptography, you can be assured that others are who they say they are. You can make spoofing and hijacking virtually impossible.

Cryptography can be used to authorize. Cryptographic information can be used to establish what rights and permissions an individual has. It can be used to prevent unauthorized use and detect attempts.

It can validate. Cryptographic information can be used to seal information in such a way that tampering or compromise is detected. Documents signed and sealed with cryptographic signatures have every byte of data validated and verifyable. This makes cheating very difficult.

It can provide audit trails. Combined with timestamping services and outside signature services, cryptography can provide a provable, step by step audit trail of events and documents.

It can insure intent. When something is encrypted, it's very difficult that another party "accidentally" received and read that information. This can go a long way to demonstrate intent of action even if you were not attempting to "hide" anything.

Cryptography goes a long way to stop a lot of lying and cheating.