Public Key Cryptography Beginner's Guide

The critical need for secrecy in electronic communications makes it necessary to use coded language. Plain text is easily understood. Cryptography means a secret language. Algorithms combine mathematical and computer systems to provide protection through keys. The keys can be public and private. Symmetric cryptography uses keys of the same type used by both sender and receiver. Asymmetric cryptography uses two types of keys, public and private keys, public to encrypt and private to decrypt.

What is Public Key Cryptography?

Mass communication refers to thousands of users who send and receive messages via digital networks. Public key cryptography makes use of two sets of keys. The purpose is to protect messages well from unlawful access. That is what happens in fraud and hacking, which are rising. Certification authorities provide public and private keys for more excellent protection. While sending, the message is encrypted with the public key. The public key may be known to many users. The message is received and decrypted with a secret key unknown to anybody except the receiver.

Cryptographic Keys, Symmetric and Asymmetric

Key refers to a bit of data used to scramble the message to prevent it from being understood. It could be numbers and/or letters. When plain text is encrypted with a cryptographic algorithm, it looks absurd. The right key would restore the original message in plain text, called decryption. If the message is GOOD NEWS and the key is abc123yz789, the encrypted message may appear as Xydfger28765. Once it is decrypted with the right key back to GOOD NEWS, it makes sense.

  • Thus, plain text plus key equals the ciphertext.

  • GOOD NEWS plus abc123yz789 equals Xydfger28765

  • Xydfger28765 plus abc123yz789 equals GOOD NEWS

The example represents symmetric cryptography with a single key. Public key cryptography uses two keys for enhanced security. The public key encrypts, and the secret key decrypts the message.

Rivest-Shamir-Adleman (RSA) Cryptography Algorithm

Among several cryptography methods, the RSA algorithm uses the public key frequently to secure messages. The internet and email are not so fortified, but the RSA algorithm provides great security like a fortress. The strength is the double keys that ensure secrecy.

RSA Advantages

Hyper security for sensitive data is ensured through the RSA system. The safety of this procedure is provided by the secrecy of the private key. Nobody can break into the data without the secret key that only the receiver possesses. Like important banking information, users are supposed to keep the private key private from everybody. If secrecy is lost, the data is in danger from cybercriminals and may be misused.

Digital signatures on documents that cannot be rejected are also provided by the public key. In the public key cryptography system, users must safeguard the secret key. The danger of misuse by one or more users arises if the secret key is revealed.

Especially in situations where large numbers of users are involved, like in social media, public key cryptography plays an important role. Secrecy is maintained through digital signatures and the keys of two types, one of which is secret, and user identities remain safe.

Effectiveness and large-scale utility have resulted in the enormous acceptance of the public key. It avoids the risks concerning symmetric keys. The public key can vary in size and scale along with the higher security and minimized dangers of leaks and disruptions by illegal means. Large organizations have approved the public key. Applications use the public key widely in many industries nowadays.

How does Public Key Cryptography help Communication?

Masking or hiding the original message is the function of encryption and decryption. During the transmission of the message, people need help understanding the meaning. Further, the message's sender cannot deny that the message was sent. The message cannot be changed with additions or deletions. No dangers come from the free distribution of the public key since only the secret key can open the message. Being more complex than symmetric-key encryption, the public key requires more mathematical calculations. The public-key encryption may not suit the need for vast amounts of data in the message. Public-key encryption can also be used to send a symmetric key that is used to decrypt added data.

The private Key-Public Key Procedure

Following the opposite of the RSA procedure also works successfully. A message encrypted with a private key can be sent to be decrypted by a public key. There are better policies concerning valuable data that can fall into the wrong hands. By public, it meant whatever information is generally known, like the news media announcements. Still, the point in favor of private key encryption is that the receiver is sure about who sent the message. Ecommerce uses such methods widely.

TLS and SSL Public Key Uses

TLS or transport layer security improved upon SSL or secure socket layer in terms of data security during transmission over the internet. A website has a TSL/SSL certificate informing numerous users of the public key. The website owns the private key that is found on the server. A TLS handshake means exchanging messages that verify each other and confirm the session keys. With the agreement, third parties cannot snoop into the notes. Sensitive data such as passwords and credit card numbers require RSA security that uses public and private keys.

PKC Diverse Applications

The digital world runs on extensive software systems and various applications that are becoming universal. One aspect unites them, and that is the need for secrecy. Digital signatures that confirm Operating Systems like Red Hat Linux packages require public keys. PGP and MIME are email encryption methods that need public keys. When documents have to be digitally signed comes the need for PKI. SSL and SSH protocols require PKI. The RFC 3161 type original timestamps need it too.

Public Key Infrastructure

A genuine Certificate Authority issues the pair of keys. A registration authority confirms user identity. PKI prepares a digital certificate that validates companies or persons. Transactions over the internet can now proceed without hassles. A robust storage place preserves public keys and certificates with a certificate management system.


Safety procedures apply in every sphere of life and more so in sensitive areas with precious information like the digital universe. RSA public key cryptography with a pair of public and secret keys provides excellent electronic message security through encryption and decryption while sending and receiving. No wonder the system is practiced globally now after universal approval commencing in the 1970s.