Alphanumeric characters are a mixture of both letters and numbers, creating a versatile range of symbols for various purposes.
Alphanumeric characters—letters (A-Z, a-z) and digits (0-9)—are a fundamental part of computer programming and data entry. They provide a compact and easily recognized character set, making them essential for identifiers, passwords, input validation, and data representation [1][3].
In programming, alphanumeric characters are used for readability, reliability of data display, and ease of typing. For instance, in Python, the underscore prefix (_) is a naming convention to indicate that a variable or method is intended for internal or private use [5]. Similarly, the at symbol (@) is used to apply decorators, which modify the behavior of functions or classes [6].
However, the use of alphanumeric characters can also present risks. Improper validation or handling of alphanumeric input can lead to security vulnerabilities. For example, Unicode and bidirectional (bidi) text using alphanumeric characters can be exploited in source code via "Trojan Source" attacks, which use Unicode control characters to visually reorder code and hide malicious behavior from reviewers [2].
In data entry, restrictions often apply to alphanumeric strings to avoid invalid or problematic characters. For instance, official documentation may forbid certain special characters alongside alphanumerics in names or identifiers to preserve data integrity and avoid processing errors [4].
Moreover, while strict use of core alphanumeric characters is often required, programming languages may also use special characters. Some special characters, like & and , are used across Romance languages, while others are specific to individual languages [7]. National characters, like letters with accent marks (e.g., é) or symbols for money (e.g., £ or €), are used in certain languages [8].
The strength of passwords recommended to use long, varied alphanumeric characters may be harder to remember and create. Using non-descriptive file names with alphanumeric characters or special characters can be beneficial for protecting sensitive information [9].
In conclusion, alphanumeric characters are crucial for textual data and coding but require careful handling to mitigate risks ranging from input errors to sophisticated code obfuscation attacks [1][2][3][4]. While extended encoding systems like Unicode are used to support characters outside the standard alphanumeric set, limiting passwords to solely alphanumeric characters makes them weaker due to reduced character set options.
Data-and-cloud computing often relies on technology that utilizes alphanumeric characters for secure data entry and programming. For instance, in data entry, alphanumeric restrictions are implemented to avoid invalid characters, while in coding, alphanumeric characters are used for readability, reliability, and in specific contexts like decorators in Python.
