TLS-RSA-EXPORT-WITH-RC4-40-MD5 Cipher Suite

Key Exchange Mechanism

Rivest, Shamir, Adleman - RSA

Grade - B

RSA key exchange does not provide perfect forward secrecy because if an attacker captures the RSA private key, they can decrypt all past communications encrypted with the corresponding public key. This is due to the static nature of the key pairs used in RSA, which contrasts with protocols like Diffie-Hellman, where ephemeral keys ensure that past sessions remain secure even if current keys are compromised.

Authentication

Rivest, Shamir, Adleman - RSA

Grade - A

RSA as an authentication mechanism in cipher suites is secure because it relies on the difficulty of factoring large prime numbers. This makes it computationally infeasible for attackers to derive the private key from the public key, ensuring confidentiality and integrity in secure communications.

Cipher

Rivest Cipher 4 - RC4

Grade - D

RC4 should not be used as a cipher due to several vulnerabilities, including biases in its keystream and susceptibility to various attacks such as the Fluhrer-Mantin-Shamir attack. These weaknesses compromise the confidentiality and integrity of encrypted data, making RC4 unsuitable for secure communications in modern cryptographic applications. Deprecated in RFC 7465.

Hash

Message Digest 5 - MD5

Grade - F

MD5 is considered highly insecure because chosen prefixes can be generated with minimal computing power. This vulnerability allows attackers to create different inputs that produce the same hash, leading to potential data breaches and integrity issues. Consequently, MD5 is unsuitable for modern cryptographic needs and should be avoided in favor of more secure algorithms.

Key Size

40 Bit - 40

Grade - F

A 40-bit cipher length is too short because it can be easily broken through brute-force attacks due to the limited number of possible keys (2^40). Modern computational power allows attackers to quickly try all potential keys, making 40-bit encryption insufficient for protecting sensitive data.