twelvecharacter

twelvecharacter is a term used in computing and information security to denote a string that consists of exactly twelve alphanumeric or printable characters. The specification is commonly applied in contexts where fixed‑length identifiers, passwords, or codes are required, such as database keys, serial numbers, and authentication tokens. By limiting a value to twelve characters, systems can balance ease of human entry with sufficient entropy for many security purposes while keeping storage and transmission overhead low.

In password policies, a twelvecharacter length is often cited as a baseline for moderate strength. When combined with a mix of uppercase and lowercase letters, digits, and special symbols, a twelvecharacter password can provide roughly 71 bits of entropy, which is considered adequate against offline brute‑force attacks using contemporary hardware. However, security recommendations vary, and longer passwords or passphrases are preferred for high‑value accounts.

Database designs sometimes employ twelvecharacter fields for unique identifiers, such as product codes or transaction IDs. The fixed size simplifies indexing and indexing structures, and it can be efficiently represented in fixed‑length columns in relational databases or as binary blobs in NoSQL stores. Some legacy systems use twelvecharacter alphanumeric codes to maintain compatibility with older hardware or software that imposes strict field length limits.

In programming, twelvecharacter strings are often validated with regular expressions that enforce length and character class constraints, for example `^[A-Za-z0-9]{12}$`. Validation routines ensure that user input conforms to the required format before processing or storage. The term may also appear in documentation for APIs, file naming conventions, and barcode specifications where a twelvecharacter field is mandated.