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Cryptography without shortcuts

Encoding, cryptography and tokens

Read a token, recognize how data is protected and test whether the application actually trusts it. Progress from URL and Base64 encoding to hashes, password protection, webhook signatures, encryption modes and JWT verification. Connect each mechanism to the problem it is meant to solve.

PLN 349planned price including tax

In your browser · No installation · Tutor and narration

FormatIn your browser, at your own pace
Syllabus10 topic areas
Edition languagePolish
Signup typeFree waitlist

Cryptography without shortcuts

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Open your browser. Start learning.

The tutor shows you.
The narrator explains. You practice.

Do not spend your first evening configuring an environment. The application, tools and task context are in one place. You do not need Docker, a VPN, a virtual machine or paid software.

See what to pay attention to

A virtual tutor walks you through the example and highlights important parts of the application, code or tool. Connect the instruction to what is happening on screen.

Hear why the result matters

Narration explains the mechanism, decision and result. Pause the guidance, return to an earlier step and work through it at your own pace.

Test your own reasoning

Take over in the exercise: change data, run a test or make a decision. Compare the result and improve your solution using the explanation.

One environment, without switching between a video and a local installation. Tools fit the topic: from HTTP requests and code to a terminal, calculator or document. Practice in simulators and prepared cases, without attacking other people's systems.

What will you be able to do?

Distinguish obscured representation from actual protection.

Do not judge token security by whether it looks random. Check the property the mechanism provides and how the recipient uses it.

Starting point

Encoding, hashing and encryption sound like similar protections.

The skill you develop

Distinguish data representation, confidentiality, integrity and authenticity.

How you test it in practice

Classify example values and explain whether reading them is normal or indicates an issue.

Starting point

You can read a JWT but do not know what must be verified.

The skill you develop

Analyze the signature, claims and authorization decision.

How you test it in practice

Connect a token change to the recipient's response. Identify the missing control instead of reporting readability alone.

Starting point

You assume a signed webhook is secure without asking further questions.

The skill you develop

Test message integrity and replay resistance.

How you test it in practice

Compare valid, modified and replayed messages. Distinguish signature verification from timestamp and event-identifier checks.

Why does this matter beyond the course?

Use this knowledge to assess tokens, webhooks and cryptographic use in applications, without designing your own algorithms.

Connect each skill to a concrete work product. Return to explanations while you practice.

A syllabus backed by materials

Specific topics.
Practice that helps you understand them.

See what makes up the syllabus: lessons, explanations, examples and exercises. The figures below describe different types of materials.

12chapters
Topic chapters in the current course materials. Subviews and indexes of the same content do not increase this count.
308narrated steps
Distinct pairs of screen text and narration after removing identical duplicates. These are guidance segments, not separate complete lessons.
75exercise variations
15 cases and 60 exercise levels on encoding, cryptography and tokens. Subsets are included only once.
156catalog entries
131 operation entries and 25 recipe entries with distinct content. The same operation may appear with different example data.

The figures describe the English-language source materials. The waiting list is for the planned Polish edition. These counts do not mean its translation is complete. Demonstration steps, examples and tasks are different units, not hours of video or counts of unique vulnerabilities.

Entry point

Who is this course for?

  • API testers and pentesters who want to explain what a token, hash or signature tells them.
  • People analyzing tokens, webhook signatures and credentials.

What helps at the start

  • Basics of HTTP and working with text. No advanced mathematics required.

Available in Polish and English — you can switch language at any time. Command names, code snippets and standard identifiers remain in their original form.

How you learn

First, understand.
Then, do it yourself.

The tutor walks through an example and explains each decision. In the exercise, return to the context, check the result and improve your answer.

  1. Understand the situation

    Goal, constraints and inputs. Know what you are testing and why.

  2. See the mechanism

    Watch a demonstration with tutor commentary, step by step.

  3. Complete the task

    Work with data, a tool or a scenario. Compare the result with your expectation.

  4. Draw a conclusion

    Justify your decision and understand its limitations. Return to anything that needs improvement.

Exercises use simulators and selected mechanisms that run in the browser. They do not require attacking other people's systems.

Planned syllabus

Know what you are learning. And why.

Each area develops a specific skill. Learn not only the topic but also the action and outcome that learning leads to.

Each topic includes a skill and a concrete exercise outcome.

I want to join the list
01Recognizing representations

Identify a value's alphabet, separators, length and usage context. Form a hypothesis about the format and test it with an appropriate transformation. Learn to describe cases where appearance alone cannot identify an algorithm.

Workshop with prepared data

What you practice
Recognize a format without attributing nonexistent protection to it.
Practical outcome
Classify captured values by representation, properties and controls. Explain whether reading them is expected.
02Encoding and normalization

Practice URL, Base64 and Base64URL encoding and Unicode character representations. Trace decoding and normalization order across application layers. See how different interpretations of the same value affect a filter and data recipient.

Tutor-guided exercise

What you practice
Trace successive transformations of the same value.
Practical outcome
Compare encoded and decoded representations. Identify the layer where interpretation changes instead of treating encoding as encryption.
03Security properties

Choose a mechanism for confidentiality, integrity, authenticity or message freshness. Compare hashing, HMAC, signing and encryption in concrete uses. Explain why compression and encoding cannot replace these protections.

Case analysis

What you practice
Distinguish message confidentiality, integrity, authenticity and freshness.
Practical outcome
Match a mechanism to the intended property. Use a case to explain why one property does not guarantee the others.
04JWT, JWS and JWE

Analyze a token's header, payload, signature or encryption. Check issuer, audience, validity, type, claim scope and key selection. Connect token verification to separate authorization for the requested operation.

Tutor-guided exercise

What you practice
Distinguish reading a token from verifying it and using it for authorization.
Practical outcome
Compare token claims, data modifications and the recipient's response. Identify the missing control that enables abuse.
05Webhook signatures

Determine which message bytes are signed and how the recipient checks authenticity. Compare a valid message with modified content, an invalid signature and a replayed event. Prepare requirements for timestamps, event identifiers and replay protection.

Tutor-guided exercise

What you practice
Test integrity and replay resistance as separate conditions.
Practical outcome
Compare valid, modified and replayed messages. Record whether signature, time and event identifier checks are performed.
06Passwords and hashes

Recognize hash formats and the role of salts and computational cost in password protection. Compare a fast general-purpose hash with a password-storage mechanism. Distinguish visible properties from information requiring code or configuration.

Case analysis

What you practice
Assess a hash's purpose and how a password is protected.
Practical outcome
Compare prepared representations and parameters. Explain the role of salts and computational cost without confusing hashing with encryption.
07Encryption, modes and randomness

Learn the role of keys, initialization vectors, nonces and integrity checks. Analyze misuse of encryption modes and repeated values in supplied examples. Identify the required security property instead of judging a solution only by its algorithm name.

Case analysis

What you practice
Recognize the importance of encryption parameters and usage conditions.
Practical outcome
Identify the effects of poor randomness or value reuse in examples. Distinguish assessing an implementation from designing an algorithm.
08Keys and certificates

Identify the purpose of key material and the relationship between public and private keys. Trace verification-key selection and distribution. Connect certificate and trust information to a specific integration.

Case analysis

What you practice
Distinguish identity, trust and the lifecycle of key material.
Practical outcome
Analyze a prepared certificate and key information. Identify the checks needed before treating a connection as trusted.
09Misuse cases

Review code that accepts a token or signed message and identify an omitted check. Connect the observed response to its cause, such as trusting unverified claims. Propose a change in the data recipient, not just a cosmetic format change.

Case analysis

What you practice
Connect misuse of a mechanism to a concrete effect.
Practical outcome
Describe user-controlled input and the recipient's decision. Explain why an unusual token appearance alone is not evidence of a flaw.
10Verifying fixes

Prepare valid, modified, expired and replayed messages. Check rejection of invalid values and preservation of legitimate integration. Summarize the security property, observations and recommendation.

Workshop with prepared data

What you practice
Verify rejection of an invalid value without blocking a valid one.
Practical outcome
Compare valid, modified and replayed versions after changing the control. Justify each test result.

In practice

What will you work on
during the course?

Each case has context, a concrete action and an outcome. The goal is not to memorize a command but to understand why the result changed.

Token analysis from format to authorization

Recognize the representation, read claims and check recipient requirements. Compare responses to content changes and the conditions for valid verification and resource access.

Work productA token analysis sheet with signature, claim and authorization tests.

A webhook resistant to modification and replay

Identify the signed content, then compare a valid message with modified and replayed versions. Explain the role of time, event identifiers and recipient-side checks.

Work productWebhook verification cases and an integration recommendation.

Certificate of completion

Finish the course.
Get the certificate.

When you complete the course, the certificate is issued automatically and emailed to you. It shows your name, the date of issue and a unique code, and its second page lists the course scope.

  • Anyone, such as an employer, can check the code without logging in.
  • The certificate is issued in English.
  • It confirms completion of the course; it is not an industry certification.

Code verification: cyberszkola.pl/verify

Sample certificate of completion, page 1, with example details and a SPECIMEN watermark
Sample certificate, page 2: course scope
Sample certificate: page 1 and the course scope on page 2. The name, date and code are examples.
Enlarge course scope
Sample certificate, page 2: course scope

Upcoming standalone course

A defined scope.
Without buying the whole path.

  • Examples of data transformations, tokens and signed messages.
  • Analysis of code and configuration for password, key and encryption protection.
  • Tasks connecting a security property to a test and recommendation.
  • Certificate of completion in English, with a verification code.

Planned course price

PLN 349including tax

Polish edition · Launch date not yet announced

Notify me at launch

Joining is free. Before sales open, you will receive the date, full scope and purchase terms. We are not taking payments today. This is a separate interest list, not a place reservation or purchase.

For companies and teams

Training for your team.
On our platform or in your LMS.

  • Company accounts, departments and licences on our platform, with progress reports for managers.
  • Delivery into your company's e-learning system. Progress and completion show up in your own reports.
  • VAT invoice issued to your company.

Compatible with LMS platforms including:

  • Moodle
  • TalentLMS
  • Cornerstone
  • Docebo
  • SAP SuccessFactors
  • Workday Learning
  • Absorb
  • 360Learning

and other platforms that support e-learning standards.

Price for companies

Individual quotedepends on the number of licences, access period and delivery method

Delivery into your company's own LMS from 50 licences.

Ask for a quote

Write to kontakt@cyberszkola.pl: the number of people, the courses you want and your LMS, if you use one.

Jacek Wlodarczyk

Project author

Jacek Wlodarczyk

Creator of Cyberwiedza, cyberszkola and AI SecLabs. In these courses, I connect explanations of mechanisms with practice, observation and decisions you need to justify.

Running a command is not enough. What matters is what its output confirms, what it does not confirm and what the next step should be.

More about the author

Before joining

Good to know.

Do I need advanced mathematics?

No. The course focuses on understanding how mechanisms are used and misused. Analyze formats, code and application responses instead of deriving cryptographic algorithms.

Does reading a JWT mean there is a vulnerability?

Not by itself. Exercises also check the signature, claims and permissions. Learn to explain whether you are seeing a normal data representation or a missing control.

Am I buying a course now?

No. This is an upcoming course announcement and an interest list. Joining is not a purchase, a place reservation or a commitment to pay.

When will it launch, and what will it cost?

The launch date, price and access terms will be announced before sales open. The interest list is how we send that information.

What language will the course use?

The course is available in Polish and in English — you can switch language at any time, and lessons, exercise explanations and narration exist in both. Commands, code and tool names keep their original syntax, as used in everyday work.

Do I need to install Docker, a VPN or my own lab?

No. All course exercises run in your browser on a computer with internet access. Training applications, terminals, editors and workshops are part of the platform. You do not install Docker, a virtual machine or a VPN, and you do not need paid external tools.

Is this just a collection of videos?

No. You work in an interactive environment. A virtual tutor highlights important elements, and narration explains the action and its result. Pause the lesson, return to earlier steps and run your own experiments. This guidance is built into the course, not individual consultation with a person.

Do the exercises act on other people's systems?

No. You use training applications, simulators and prepared data. Learn the mechanism and its limitations in a safe environment. External resources are supplementary, not required to complete the exercises.

Will I receive a certificate or a job guarantee?

Yes, a certificate of completion. When you complete the course, you receive a certificate in English with a unique code that anyone can check at cyberszkola.pl/verify. It confirms completion of the course and is issued by the author; it is not an industry certification. We do not promise employment.

Are these official OWASP or ISO courses?

No. These are independently authored courses using public references and original cases. They do not replace licensed standards, accreditation or qualifications required in regulated industries.

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Planned price: PLN 349 including tax

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  • The full offer before you decide to buy
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You can withdraw your consent at any time. This signup covers the selected course — we will not add you to the lists for the other courses automatically.