Science of secure messaging encryption explained

Digital communication today requires encryption to remain secure. Whether it’s a bank transaction or private conversation, encryption helps secure sensitive information. Message apps and services that use encryption are common. Messages and files can be exchanged confidentially using these services.

Basis for secure messaging

Scrambling and unscrambling information requires the use of a shared secret key. Algorithms that use symmetric encryption use plaintext as input and produce ciphertext as output. Decrypting the ciphertext back into plaintext requires the same key.

1. A secret key is generated, shared, and installed on both devices. This key acts like a password.
2. The sending device uses the algorithm and key to encrypt the plaintext message into unintelligible ciphertext.
3. The ciphertext is transmitted to the receiving device.
4. The receiving device uses the same algorithm and secret key to decrypt the ciphertext back into the original plaintext message.

what is private message? The security of symmetric encryption depends on keeping the key secret. As long as the key remains known only to the sender and recipient, the system provides confidentiality. However, the need to securely share the secret key is a weakness of symmetric encryption methods.

Securing the secret keys

To overcome the key-sharing problem in symmetric encryption, secure messaging apps use a system called public key encryption. The secret symmetric keys used to encrypt messages can be encrypted using this method. Public key encryption uses keys with a public key and a private key. Private keys must remain secret, whereas public keys are shared openly. By mathematically related keys, data encrypted with the public key can only be decrypted with the corresponding private key. This one-way relationship enables the public key to be freely distributed without compromising the private key. Here is how public key encryption is used in secure messaging:

1. Each device generates its public-private key pair.
2. All public keys are shared openly on a central server or exchanged between devices.
3. To encrypt a message, the sending device uses the recipient’s public key to encrypt the symmetric key.
4. The encrypted symmetric key and ciphertext message are transmitted.
5. The receiving device decrypts the symmetric key using its private key.
6. Decrypting the ciphertext into the original plaintext message is done with the decrypted symmetric key.

Using asymmetric public key encryption, the public key is securely transmitted, thereby solving the key-sharing problem. The private keys remain safely on each user’s device only. Common public key algorithms used in secure messaging include RSA and ECC. RSA relies on the difficulty of factoring large prime numbers to generate keys. ECC uses properties of elliptic curves over finite fields for key generation. Both produce computationally secure key pairs suitable for encryption.