Hash algorithms
A hash function is a cryptographic algorithm that is used for message authentication. A hash function takes a message of arbitrary length and produces an output of fixed length, called a message digest or fingerprint. Hash functions are used to verify that messages have not been tampered with.
The vRouter supports the following hash functions.
| Cipher | Description |
|---|---|
MD5 | MD5 is the most recent version of message digest algorithm. MD5 takes a message of arbitrary length and produces a 128-bit condensed digital representation, called a message digest. It is often used when a large file must be compressed and encrypted, then signed with a digital signature. Message digest is quite fast and efficient compared with SHA-1 because it uses primitive operations and produces a shorter message. However, it is not as secure as SHA, and has reportedly been compromised in some ways, though not yet in ways that make it insecure. |
SHA-1 | SHA stands for Secure Hash Algorithm, also known as the Secure Hash Standard. The SHA hash functions are five one-way cryptographic algorithms for computing a message digest. SHA-1 is an extension of the original SHA, and is the standard hash algorithm supported by the U.S. government. SHA-1 takes a message of arbitrary length (the message must be smaller than 2^64 bits) and produces a 160-bit message digest. SHA-1 is slower than MD5, but it is more secure because the additional bits in the message digest provide more protection from brute-force attacks. |
| SHA-2 | SHA-2 is a stronger algorithm than SHA-1 with a longer hash value. The vRouter supports 256-bit, 384-bit, and 512-bit SHA-2 algorithms, which are used to calculate a 128-bit hash message authentication code (HMAC) to verify the message. |