Malleability (cryptography)

Malleability in cryptography means that it's possible to change a secret message in a way that still lets someone read it without knowing the original message. Imagine you have a piece of clay - it can be squished and molded into different shapes, but it's still clay. Similarly, a secret message can be altered or "squished" in a way that makes it look different, but it remains decipherable to someone who knows what to look for.

This can be a big problem in cryptography because if someone can change a secret message without being noticed, it means they could potentially distort the original message for their own purposes. Imagine if you sent a message to your friend asking for help, but someone else changed it to say something mean or embarrassing. That wouldn't be very nice, would it?

So, to prevent this from happening, cryptographers use something called a "digital signature" to make sure that messages can't be tampered with. Think of a digital signature like a special stamp that only the person sending the message can use. When they stamp the message with their signature, it locks it in place and ensures that no one can change it without being detected.

In summary, malleability in cryptography means that secret messages can be altered without being noticed, but cryptographers use digital signatures to prevent this from happening so that messages remain secure and can be trusted.