Applications of Cryptography

Imagine a world without encryption—your emails, banking transactions, and private messages would be vulnerable to prying eyes. Sounds terrifying, right? In today’s hyper-digital era, cryptography isn’t just a fancy concept used by hackers and cybersecurity experts—it’s the backbone of data security.

According to a Markets and Markets report, the global encryption software market is projected to expand significantly from $10.9 billion in 2020 to $22.1 billion by 2025, reflecting an increasing reliance on cryptography to protect sensitive data. With cyberattacks becoming more sophisticated, cryptography has evolved beyond simple password protection into a complex, multi-layered defense mechanism.

Cryptography has countless real-world applications, from securing online transactions to encrypting confidential emails. Let’s dive deep into its various applications, covering everything from Public Key Infrastructure (PKI) to email encryption tools like FlowCrypt and RMail.

Public Key Infrastructure (PKI)

Public Key Infrastructure (PKI) is like a digital passport system that verifies identities online. It uses two keys:

• Public Key: Shared with everyone.
• Private Key: Kept secret by the owner.

These keys work together to encrypt and decrypt data, ensuring secure communication. PKI is widely used in:

• Secure email communications (S/MIME certificates)
• Digital signatures (to verify authenticity)
• SSL/TLS certificates (for secure web browsing)

How does PKI Work?

When you access a website secured by SSL/TLS, your browser checks the site’s digital certificate issued by a trusted authority (like DigiCert or Let’s Encrypt). This ensures that the website is legitimate and not a phishing attempt.

Digital Signatures: Ensuring Data Authenticity
A digital signature is a cryptographic process used to verify:

• Authentication: Verifies the sender’s identity.
• Integrity: Ensures that the message remains unchanged.
• Non-Repudiation: The sender cannot deny signing the document.

How It Works:

1. A hash of the message is created.
2. The hash is signed with the sender’s private key, generating a digital signature.
3. The recipient verifies the signature’s authenticity using the sender’s public key.

Digital signatures are widely used in emails, online contracts, and software verification.

CA vs. Self-Signed Certificates (SSC)
Public Key Infrastructure relies on Certificate Authorities (CAs) to issue trusted digital certificates. However, some organizations use Self-Signed Certificates (SSC), which are generated internally without verification from a CA.

• CA-signed certificates, issued by a trusted authority, provide global recognition.
• Self-signed certificates are created by users but are not trusted by default in browsers.
• CAs provide revocation options (CRL, OCSP), while self-signed certificates do not.

While self-signed certificates are useful for internal networks, they are not recommended for public-facing websites due to security risks.

SSL vs. TLS: Understanding Secure Communication Protocols
Secure Socket Layer (SSL) and Transport Layer Security (TLS) are cryptographic protocols that protect data during online communication.

• SSL (Older versions): Used before TLS but has known vulnerabilities.
• TLS (Modern standard): More secure and faster than SSL.

Most websites today use TLS 1.2 or 1.3 instead of outdated SSL versions to provide better encryption, faster performance, and stronger authentication.

How TLS/SSL Handshake Works?
When you visit a secure website (HTTPS), a TLS/SSL handshake occurs:

1. Client Hello: The browser requests a secure connection.
2. Server Hello: The server replies with its SSL/TLS certificate.
3. Key Exchange: The client verifies the certificate and negotiates encryption settings.
4. Session Key Generation: A shared secret key is generated.
5. Secure Communication Begins: Encrypted communication starts.

This process ensures that data is securely encrypted between the browser and the website.

Session Resumption in TLS
TLS Session Resumption allows faster secure connections by reusing previous session data instead of performing a full handshake every time.

• Session ID Method: The server stores session details for later reuse.
• Session Ticket Method: The session data is stored on the client instead.

This technique improves speed, reduces server load, and enhances performance, especially for frequently accessed websites.

Encryption in Cloud Computing

With the rise of AWS, Google Cloud, and Microsoft Azure, businesses store massive amounts of data in the cloud. However, without proper encryption, this data is vulnerable to cyberattacks. Cloud providers use cryptographic techniques like:

• AES (Advanced Encryption Standard) is used to secure data at rest.
• TLS (Transport Layer Security) encrypts data during transmission.
• Homomorphic encryption allows the computation of encrypted data without decrypting it.

Cryptography in Blockchain and Cryptocurrencies

Blockchain technology, the backbone of Bitcoin, Ethereum, and NFTs, relies heavily on cryptography. It uses:

• Hash Functions (SHA-256) to secure transaction data.
• Transactions are signed and verified using public and private keys.
• Zero-knowledge proofs (ZKP) to enhance privacy in transactions.

How Cryptography Secures Blockchain?

Each block in a blockchain contains the following:

1. A cryptographic hash of the previous block.
2. A timestamp recording when the block was created.
3. Transaction data is securely stored through encryption.

This makes blockchain an ultra-secure and tamper-proof ledger, revolutionizing industries like finance, healthcare, and supply chain management.

Email Encryption: Protecting Your Digital Conversations

Have you ever sent a confidential email? If it wasn’t encrypted, attackers could intercept and read it. Email encryption tools use cryptography to protect sensitive messages.

How to Encrypt Emails Using FlowCrypt (OpenPGP)?

Follow these steps to send a secure email to Gmail using FlowCrypt, a browser extension that enables OpenPGP encryption.

At the Sender’s End:

1. Enable Open PGP in your Chrome or Firefox browser.
2. Log in to Gmail using https://mail.google.com.
3. Click on Secure Compose in the left pane.
4. Enter the recipient’s email in the Add Recipient field.
5. If the recipient’s name appears in green, they also have FlowCrypt installed.
6. Add Subject and Body, then click Encrypt, Sign, and Send.

At the Recipient’s End:

1. The recipient clicks on the encrypted email.
2. If required, they enter their PGP passphrase to decrypt it.

This ensures that the email is accessible only to the intended recipient.

PGP and GPG: Strong Email Encryption
Pretty Good Privacy (PGP) and its open-source alternative GPG (GNU Privacy Guard) are encryption tools that protect emails and files.

• PGP employs both symmetric and asymmetric encryption methods.
• GPG is an improved, open-source version of PGP.

How PGP Works:

1. A message is encrypted with a symmetric key (fast encryption).
2. The recipient’s public key encrypts the symmetric key for a secure exchange.
3. Using their private key, the recipient decrypts the symmetric key to access the message.

This ensures secure email communication, file encryption, and identity verification.

Web of Trust (WoT): A Decentralized Trust Model
Unlike PKI, which relies on trusted Certificate Authorities (CAs), the Web of Trust (WoT) is a decentralized model where:

• Users manually verify and sign each other’s public keys.
• Trust is built through multiple endorsements, reducing reliance on centralized CAs.
• Commonly used in PGP and GPG encryption to authenticate identities without a central authority.

WoT is useful in privacy-focused communities and open-source projects where users rely on peer verification instead of corporate CAs.

Popular Email Encryption Tools

Apart from FlowCrypt, there are several other email encryption tools available:

1. RMail: RMail provides email tracking, encryption, e-signatures, and large file transfers. It integrates seamlessly with Outlook, Gmail, and other platforms.

2. Mailvelope : A browser extension that enables OpenPGP encryption for webmail services like Gmail and Outlook.

3. Virtru : A robust encryption tool that provides end-to-end email protection with access controls and audit logs.

4. Webroot™ : A cybersecurity suite that includes email encryption alongside malware protection.

5. Secure Email (S/MIME) Certificates : S/MIME uses PKI-based encryption to sign and encrypt emails, ensuring authenticity.

6. Proofpoint Email Protection: An enterprise-level security tool that prevents phishing, malware, and email fraud.

7. Paubox: HIPAA-compliant email encryption solution used by healthcare providers.

Master CEH with InfosecTarin

Cryptography is not just for tech geeks—it’s an essential part of our digital lives. From securing emails with FlowCrypt and RMail to protecting financial transactions with blockchain, cryptography ensures that our data remains confidential and tamper-proof.

With cybersecurity threats evolving daily, implementing cryptographic solutions is no longer optional—it’s a necessity. Whether you’re an individual looking to protect your emails or a business securing customer data, InfosecTrain’s Certified Ethical Hacker (CEH) Training equips you with the skills needed to think like a hacker and secure systems proactively. Our expert-led CEH course covers penetration testing, vulnerability assessment, and real-world attack simulations, ensuring hands-on learning aligned with industry best practices.

Whether you’re an aspiring Ethical Hacker, cybersecurity professional, or IT administrator, this training prepares you to pass the CEH exam with confidence and tackle modern cyber threats effectively.

Take the first step toward mastering ethical hacking! Enroll in InfosecTrain’s CEH Training today!

TRAINING CALENDAR of Upcoming Batches For CEH v13

Start Date	End Date	Start - End Time	Batch Type	Training Mode	Batch Status
13-Dec-2025	18-Jan-2026	19:00 - 23:00 IST	Weekend	Online	[ Open ]	Enroll Now
03-Jan-2026	08-Feb-2026	19:00 - 23:00 IST	Weekend	Online	[ Open ]	Enroll Now
17-Jan-2026	01-Mar-2026	09:00 - 13:00 IST	Weekend	Online	[ Open ]	Enroll Now
07-Feb-2026	15-Mar-2026	19:00 - 23:00 IST	Weekend	Online	[ Open ]	Enroll Now