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TLS-KRB5-WITH-RC4-128-MD5 Cipher Suite
A breakdown of the Cipher Suite TLS_KRB5_WITH_RC4_128_MD5, its strengths, and its weaknesses.
Key Exchange Mechanism
Kerberos 5 - KRB5
Grade - C
Low usage
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
128 Bit - 128
Grade - A
128-bit symmetric encryption keys are considered secure because they provide an astronomically large number of possible combinations (2^128), making brute-force attacks computationally infeasible with current technology. This level of security is sufficient for most practical purposes and is widely adopted in various encryption protocols.
