computer security
12 articles tagged computer security.
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How AWS IAM Policy Evaluation Works
Learn how IAM combines identity, resource, boundary, and organization policies—and why one matching deny defeats every allow.
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TLS 1.3 Handshake and Shared Traffic Keys
How TLS 1.3 combines ephemeral Diffie–Hellman, transcript hashes, and Finished messages to create keys and detect tampering or downgrade attempts.
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AES-GCM Nonces, Counters, and Authentication Tags
How AES-GCM encrypts with a nonce-derived counter stream, authenticates data with a tag, and fails catastrophically when nonces repeat.
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Argon2 Memory-Hard Password Hashing
How Argon2 uses configurable time, memory, and parallelism costs to make offline password guessing expensive.
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OAuth 2.0 PKCE and Authorization Code Binding
PKCE binds an OAuth authorization code to the client request that created it, preventing intercepted codes from being redeemed by an attacker.
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AWS Signature Version 4 Request Authentication
How AWS SigV4 canonicalizes requests, derives scoped HMAC keys, checks timestamps, and proves a request was not altered.
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Linux User Namespaces and UID/GID Mapping
How Linux maps container UIDs and GIDs so root inside a user namespace is an unprivileged identity on the host.
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AEAD Nonces and the Cost of Reuse
How AEAD nonces protect encryption, why each must be unique per key, and how reuse can expose plaintext and enable forgeries.
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AWS STS AssumeRole and Temporary Credentials
Understand how AWS STS validates a caller, issues role credentials, separates trust from permissions, and refreshes expiring sessions.
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Linux Seccomp-BPF System Call Filters
How Linux seccomp-BPF examines system calls and lets a process allow, reject, trap, or kill them.
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AWS IAM Policy Evaluation
How IAM combines identity, resource, boundary, and session policies—and why any applicable explicit deny wins.
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AEAD Nonce Reuse and Its Security Consequences
Why reusing an AEAD nonce exposes plaintext relationships and can enable forgeries—and why protocols must prevent it.