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No. Base64 is encoding (reversible, anyone can decode it), NOT encryption (which requires a secret key to decode). Never use Base64 to "hide" sensitive data — it provides zero security. Use it for binary-to-text conversion in systems that only support ASCII (email, JSON, HTML data URIs).

Never use MD5, SHA-1, SHA-256, or SHA-512 directly for passwords — they are too fast (billions of hashes/second). Use bcrypt, scrypt, or Argon2 which are designed to be slow and include salting. In Node.js: bcryptjs or argon2 packages. In PHP: password_hash() with PASSWORD_BCRYPT.

UUID v4: 128-bit random, not sortable, standard format (8-4-4-4-12 hex with dashes). ULID: 128-bit, first 48 bits = timestamp (sortable!), last 80 bits = random, base32 encoded (26 chars, no dashes). ULIDs are better for database primary keys where you want time-ordering without sequential IDs that reveal counts.

encodeURIComponent: encode a single value going inside a URL (encodes &, =, ?, /, #, + and all special characters). encodeURI: encode a complete URL (does NOT encode ?, &, =, /, # as these are valid URL structure). Rule: if encoding a query parameter value, use encodeURIComponent.

JavaScript RegExp: /pattern/flags. Common flags: g (global, find all matches), i (case-insensitive), m (multiline, ^ and $ match line starts), s (dotAll, . matches newline). Methods: string.match(), string.replace(), regex.test(), regex.exec(). Use regex101.com for interactive testing with full explanation.