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Cryptographic Attacks

Cryptographic systems carry their own risks, including weak ciphers, misconfigured implementations, compromised keys, and protocol downgrade attacks. This content also addresses long-term threats to encrypted data, including the growing implications of quantum computing.

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About this video

Cryptography protects sensitive data, but the security it provides depends heavily on the decisions made during implementation. Selecting weak or deprecated ciphers, supporting an overly broad range of cipher suites, or configuring inadequate key lengths can all undermine an otherwise sound system. Certificate management also requires ongoing attention, as expired certificates and the acceptance of self-signed certificates can erode user trust and open the door to impersonation attacks. These are not one-time decisions but require periodic re-evaluation as standards evolve and formerly acceptable configurations become liabilities. On the attack side, compromised key attacks occur when a private key is stolen or accessed without authorization, potentially allowing an attacker to impersonate a trusted server. Collision and birthday attacks target weaknesses in hashing algorithms, while downgrade attacks, commonly seen with TLS, use a man-in-the-middle position to force communication down to weaker, less secure protocol versions. Balancing which TLS versions and cipher suites to support requires precision, since being too permissive creates security gaps and being too restrictive can exclude legitimate users. The longer-term threat landscape is shaped significantly by advances in computing power, particularly quantum computing. Current encryption standards are calibrated to resist today's hardware and software, but quantum systems are exceptionally well-suited to cryptanalytic tasks and could render many existing standards obsolete far sooner than traditional computing would. The "store now, decrypt later" approach poses a concrete risk for data that will remain sensitive years into the future, as adversaries may already be capturing encrypted traffic with the intent to decrypt it once quantum capabilities mature. Organizations handling highly sensitive long-term data should evaluate post-quantum cryptographic strategies now rather than waiting for the threat to become immediate.

What you'll learn

Identify common cryptographic vulnerabilities and attack types, including weak ciphers, compromised keys, collision attacks, and downgrade attacks
Explain the security implications of quantum computing and the store-now-decrypt-later threat model for long-term data protection

What's covered

Cryptographic Vulnerabilities & Attacks

Cryptographic Vulnerabilities
- Weak Ciphers
  - Choose Strong Ciphers
  - Key Length Matters
- Cipher Suite Selection
  - Re-evaluate Over Time
  - Implementation Method
- Certificate Errors
  - Expiring Certificates
  - Self-Signed Certificates
Cryptographic Attacks
- Compromised Key Attack
  - Stolen Private Key
  - Website Impersonation
- Collision & Birthday Attacks
  - Hashing Algorithm Weakness
- Downgrade Attack
  - TLS Version Targeting
  - Machine in the Middle
  - Weak Cipher Suite Forced
Future Cryptographic Concerns
- Quantum Computing Threat
  - Faster Cipher Cracking
  - Current Standards at Risk
- Store Now Decrypt Later
  - Intercepted Sensitive Data
  - Future Decryption Risk
- Long-Term Data Protection
  - Exceed Current Encryption Standards

Key terms

Cipher: An algorithm used to encrypt and decrypt data.
Encryption: The process of converting readable data into an unreadable format using an algorithm and key to prevent unauthorized access.
Hash Function: A mathematical algorithm that converts input data of any size into a fixed-size output value used to verify data integrity.
Transport Layer Security: A cryptographic protocol that provides secure communication over a network, successor to SSL.
Downgrade Attack: An attack in which a man-in-the-middle forces two communicating parties to negotiate a weaker cryptographic protocol or cipher suite than they would otherwise use.
Collision Attack: An attack against a hash function that attempts to find two different inputs producing the same hash output, undermining data integrity verification.
Compromised Key Attack: An attack in which a threat actor obtains unauthorized access to a cryptographic key, allowing them to decrypt data or impersonate a legitimate entity.
Quantum Computing: A computing paradigm that uses quantum mechanical phenomena to perform calculations, posing a significant future threat to current cryptographic standards.
Store-Now-Decrypt-Later: A threat model in which an adversary captures and stores encrypted data today with the intent to decrypt it in the future using more powerful computing, such as quantum systems.

Topics

Cryptography Cryptographic Attacks Quantum Computing Post Quantum Cryptography Downgrade Attacks Key Management

Transcript

Cryptography has its own vulnerabilities

One thing that cryptography allows us to do is secure our information and make sure that we're not vulnerable to attacks. However, cryptography itself can have its own vulnerabilities.

One of the things to really watch out for is weak ciphers. There are a lot of ciphers out there, so make sure you're choosing a cipher that's considered strong. Another thing that you'll be choosing is which cipher suites you're going to be supporting. So for instance, let's say you have a web server and you are selecting which cipher suites that web server is going to support. You're going to need to know the details of the cipher suites to choose, and which ones are acceptable and not acceptable. Not only that, but since things change over time, you'll have to go back and revisit and re-evaluate that to make sure that you don't have any ciphers that have changed, cipher suites that have changed and should no longer be supported.

Not only is choosing the right cipher suites and the right ciphers going to be important, but how you implement it. There are many different ways that you can implement some of these ciphers, and choosing the right way to implement could make a big difference in how secure it is. One example might be if you have a choice of the key length. Key length is going to be really important to how strong that cipher is.

Another thing to watch out for is certificate errors. Watch for things like certificates expiring. Also be concerned about issuing any kind of self-signed certificates, that could desensitize your users into accepting things that they shouldn't accept.

Cryptographic attacks

From an attack standpoint, one of those attacks is the compromised key attack. Just like it sounds, it means that a key has been compromised, or there is someone who has stolen a key or has gained access to a key that shouldn't have access to it. If that's the private key, this can be a lot of problems, because somebody can impersonate your website.

Another thing to watch out for is collision attacks, or birthday attacks. This has to do with your hashing algorithms, and the hashing algorithms you choose, and making sure that they're not susceptible to these types of attacks.

One of the things to watch out for is a downgrade attack. That's when there is some sort of machine in the middle that's tricking the communication to communicate not at the proper level. Let me use TLS as an example of this. When you are a web administrator, you're going to choose which TLS versions you're going to support. You're going to draw a line here, and if you draw the line too low, that means you're supporting more TLS versions than you should, and then you're going to have clients connecting and it's going to be in an insecure manner. But if you draw it too high, then you're going to be excluding some of your customers or some of your clients that would normally be connecting to your site. So you have to draw the line at the right spot.

But whatever you are supporting, a downgrade attack will try to trick this communication into bringing it down to a lower level than it should be. TLS also has the cipher suites that it's going to support. Support too many cipher suites and it also makes it susceptible to this downgrade attack. Since some of this communication from the beginning is not encrypted, there could be a machine in the middle that gets involved and then downgrades the capabilities of the user, and in doing so the communication from then on is going to be at a weaker quality, not at today's standards.

Thinking about the future

In some situations, like websites, we may not be concerned with security 10 years from now. That is, we can implement standards that are considered secure now and we're probably not going to be too concerned with a lot of our sites. However, if it's data that still needs to be secure and relevant 10 years from now, that could be more of a concern, because as we know, the current encryption standards meet our current needs, not our needs 10 years from now. Computers and software and hardware are getting faster and faster at decrypting stuff, or this cryptanalysis where they can reverse engineer this. So we just have to think about that long term.

One of the concerns is with quantum computing. With regular computing, things like our CPUs and our integrated circuits, we have a fairly predictable timeline of when we can crack certain ciphers and when we're getting close to that. However, quantum computing is going to really change things, and that is, it's really set up well to do cracking, to crack ciphers, to figure things out. Because of that, it could really cause problems with a lot of our current standards.

Quantum computing isn't at a level that we need to be all that concerned, at least for a lot of our data, that is, it's not data that's going to be really sensitive five or 10 years from now. However, there is this idea of store now and decrypt later. There could be intercepting communication that's happening now, and let's say it's top secret information that could still be sensitive 5 or 10 years from now. They could have that information, have captured it, and then decrypt it later. That can be problematic, which is one of the reasons that if you do have really super sensitive information and it will be for the next 5 or 10 years, you need to be thinking at a level that's greater than our typical encryption level that we have right now.

So there are some considerations when it comes to implementing cryptography: some vulnerabilities that you need to consider, some attacks, and how are we going to secure things in the future if it's important 5 or 10 years from now.

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