Which cryptographic method is best suited for protecting files while in transit over email?

Pretty Good Privacy (PGP) is particularly well-suited for protecting files while in transit over email. It utilizes a combination of data compression, symmetric-key cryptography, and public-key cryptography, making it a robust choice for ensuring confidentiality and integrity of the data being sent.

When a file is encrypted with PGP, it can only be decrypted by someone who possesses the corresponding private key, ensuring that unauthorized parties cannot access the contents of the email. Additionally, PGP offers digital signatures that allow the recipient to verify the authenticity of the sender, thus providing both security and trust in email communications.

In contrast, IPSec primarily focuses on securing IP packets and is more suited for creating secure network connections rather than specifically protecting email content. Linear Cryptanalysis is an attack method rather than a cryptographic solution, and Authentication Headers (AH) are part of the IPSec protocol designed to ensure data integrity and authenticity but do not provide encryption. Therefore, for securing email files specifically during transit, PGP is the most appropriate and effective choice.