Defective Sign & Encrypt in S/MIME, PKCS#7, MOSS, PEM, PGP, and XML
D. D. Davis · 2001
Simple Sign & Encrypt, by itself, is not very secure. Cryptographers know this well, but application programmers and standards authors still tend to put too much trust in simple Sign-and-Encrypt. In fact, every secure e-mail protocol, old and new, has codified naive Sign & Encrypt as acceptable security practice. S/MIME, PKCS#7, PGP, OpenPGP, PEM, and MOSS all suffer from this flaw. Similarly, the secure document protocols PKCS#7, XML-Signature, and XML-Encryption suffer from the same flaw. Naive Sign & Encrypt appears only in file-security and mailsecurity applications, but this narrow scope is becoming more important to the rapidly-growing class of commercial users. With file- and mail-encryption seeing widespread use, and with flawed encryption in play, we can expect widespread exposures.