Developer Glossary
Clear definitions of common developer terms covering cryptography, encoding, HTTP, and data formats.
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B
Base64
An encoding scheme that converts binary data into a string of 64 printable ASCII characters for safe transport over text-based protocols. Increases size by ~33%.
bcrypt
A password hashing function designed to be computationally expensive, making brute-force attacks slow. Uses a configurable work factor (cost) to scale with hardware improvements.
C
CORS
Cross-Origin Resource Sharing — a browser mechanism that allows servers to declare which external origins may access their resources via HTTP headers.
Cron Expression
A string of five fields (minute, hour, day-of-month, month, day-of-week) that defines a recurring schedule for automated jobs in Unix-based systems.
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H
Hash Collision
When two different inputs produce the same hash output. Cryptographically secure hash functions make collisions computationally infeasible. MD5 and SHA-1 have known practical collisions.
HMAC
Hash-based Message Authentication Code — combines a cryptographic hash function with a secret key to verify both data integrity and authenticity.
HTTP Status Codes
Three-digit codes returned by servers to indicate the result of an HTTP request. Grouped as 2xx success, 3xx redirect, 4xx client error, 5xx server error.
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JSON
JavaScript Object Notation — a lightweight text format for structured data using objects, arrays, strings, numbers, booleans, and null. The universal API data format.
JWT (JSON Web Token)
A compact, URL-safe token format for transmitting claims as a signed JSON object. Consists of three Base64URL-encoded sections: header, payload, and signature.
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R
Rainbow Table
A precomputed table mapping hash values back to their original inputs, used to crack unsalted password hashes quickly. Salted hashing defeats rainbow table attacks.
Regular Expression (Regex)
A sequence of characters that defines a search pattern for matching, extracting, and replacing text. Uses character classes, quantifiers, anchors, and groups.
RSA
A public-key cryptosystem used for encryption and digital signatures. RSA security relies on the difficulty of factoring large integers. RSA-2048 is the minimum recommended key size.
S
Salt (Cryptographic)
A random value added to a password before hashing to ensure that identical passwords produce different hashes. Salts defeat rainbow table attacks and precomputed hash lookups.
SHA-256
A cryptographic hash function from the SHA-2 family that produces a 256-bit digest. The standard choice for data integrity verification and digital signatures.
U
URL Encoding
Converts characters that are unsafe or reserved in URLs into a percent sign followed by two hexadecimal digits (e.g., space → %20). Defined in RFC 3986.
UUID (Universally Unique Identifier)
A 128-bit identifier standardized in RFC 9562, displayed as 32 hex digits in five groups. Generated without coordination while maintaining practical uniqueness.