Cryptography and Key Management

As leading consultants in the application of cryptography, our aim is to share with you an insight into how and why cryptography should be used in today’s modern world of keeping digital data safe.

Modern cryptography today works to keep digital information immune and secure from unauthorised discovery and manipulation by applying mathematical techniques (algorithms) to the target data.

Security and Privacy

 Encryption outlined  Decryption outlined


Algorithm is applied to the plaintext input to create ciphertext


Reverse the process to get plaintext from ciphertext

Encryption of data is a critical step in assuring privacy and security.

Looking at the recent horror stories of cyber-crime tells us that these cryptographic processes have not been applied correctly if at all, hence making the data vulnerable to hackers.

Once encryption is applied with an algorithm correctly it is practically very difficult and uneconomic for an attack to be successful. Looking at the recent horror stories of cyber-crime tells us that these cryptographic processes have not been applied correctly if at all, hence making the data vulnerable to hackers. The celebrated Dutch cryptographer Auguste Kerchoffs in 1893 first provided the fundamental principle of cryptography. He states that the security should not be dependent on knowing the mathematical process of encryption, the algorithm, but only on keeping the key which drives the algorithm secret.

In other words, unless you know the key you can’t break the algorithm.

By applying encryption this empowers the service of confidentiality. By converting your plain text to cipher text you can be assured that your private information is kept confidential and safe. Following Kerchoffs principles, organisations providing these confidentiality services should ensure the safety of the secret key. This solution should be provided by storing security keys in a Tamper Resistant Module (TRM) which is anything from a smart card to a cryptographic appliance known as a Hardware Security Module (HSM).

Data Integrity

dataintegrity small



Points to consider

  • E-commerce and e-payments depend on confidentiality and data integrity
  • Basic encryption will not provide protection for data integrity
  • For data integrity, you need a cryptographic checksum
  • When using public key cryptography these checksums are called digital signatures
  • A digital signature also provides non-repudiation which prevents denial by the sender

With electronic payment messages, the last thing that you want to experience is for the payment data to be modified by a hacker without detection.

For electronic payments and e-commerce generally, cryptographic checksums are essential for tracking any malicious changes. The checksum doesn’t stop unauthorised changes but ensures they can be detected. What data integrity requires is a checksum or digital signature to show you if the data has been changed.

At Microexpert, we advise clients on the use of cryptographic techniques in all forms of digital data protection that include:

  • Data privacy
  • Electronic payments and transactions
  • Digital currencies and blockchain applications
  • Internet Of Things (IOT)
  • Industrial Control Systems (ICS)

We use agile development techniques for embedded cryptographic systems in the following hardware devices:

  • Hardware Security Modules (HSMs)
  • Secure Elements (SE)
  • Smart cards and secure MicroSD cards
  • Cryptographic tokens
  • Mobile devices

We will listen to your requirements and advise you on the best way to go. We can also design and develop solutions both proof of concept and production to match your needs.


If you are researching or planning a project or just need some friendly advice.

Call +44 (0)1903 723 548 or email us at m.


+44 (0) 1903 723 548

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Gratwicke House
10 East Street
West Sussex
BN17 6AW, UK

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