16character

16character is a term used in computing to describe a string that contains exactly 16 characters. It is commonly used to designate fixed-length identifiers and tokens across software systems. The allowed character set varies by implementation, ranging from digits and uppercase letters only to mixed-case alphanumeric sets, or to broader encodings such as base32 or base62.

Generation and encoding: A 16-character token can be produced by encoding binary data into text or by truncating a longer identifier. Common encodings include hex (base16), base32, base62, and base64url without padding. When security is required, tokens should be generated with a cryptographically secure random number generator before encoding; truncation reduces entropy, if used.

Applications: 16-character strings are used as fixed-length identifiers in databases and APIs, as session tokens, license keys, discount codes, or short codes in URLs. Their fixed length helps with indexing and predictable storage, but may require careful design to avoid collisions in large datasets.

Security and limitations: The security provided by a 16-character token depends on the alphabet size and the randomness of the source. For example, 16 characters drawn from a 16-symbol hex alphabet yield up to 64 bits of entropy, while a 16-character base62 string can approach about 95 bits. Length alone does not guarantee security; use unpredictable randomness and appropriate rate limiting and validation.

See also UUID, token, cryptographic hash, and short URL encoding.