Which hashing algorithm is commonly associated with digital signatures?

The hashing algorithm commonly associated with digital signatures is SHA-1. SHA-1, which stands for Secure Hash Algorithm 1, produces a fixed-size hash value from variable-length input data. This characteristic makes it suitable for use in digital signatures, where data integrity is paramount. When a message is signed, the hash of the message is computed using SHA-1, and then this hash is encrypted with a private key to create the digital signature. This ensures that any alteration of the message would result in a different hash, indicating a breach of integrity.

Although other algorithms mentioned, like RSA and MD5, play important roles in cryptography, they serve different purposes. RSA is primarily an asymmetric encryption algorithm, used for encrypting and signing data but not as a hashing method. MD5 is also a hashing algorithm but has known vulnerabilities which render it unsuitable for strong security applications like digital signatures. Flake8, on the other hand, is a style guide enforcement tool for Python code and is not relevant to hashing or digital signatures at all. Thus, SHA-1 remains a primary choice for hashing in digital signature applications, despite its deprecation in favor of more secure algorithms in recent years.