KangarooTwelve is a family of fast and secure extendable-output functions (XOFs), the generalization of hash functions to arbitrary output lengths, with two instances: KT128 and KT256. Derived from Keccak, these functions aim at higher speeds than FIPS 202's SHA-3 and SHAKE functions, while retaining their flexibility and basis of security. On high-end platforms, they can exploit a high degree of parallelism, whether using multiple cores or the single-instruction multiple-data (SIMD) instruction set of modern processors. Some examples:

• On current Intel architectures with AVX2, KT128 tops at 1.4 cycles/byte for long messages on a single core, and at 0.51 cycles/byte with AVX-512.
• On the latest Apple 14 and M1 processors, KT128 can take advantage of the ARMv8-A's SHA-3 dedicated instructions to deliver 0.75 cycles/byte for long messages on a single core. This is 1.7 times (resp. 3 times) faster than SHA-256 (resp. SHA-512), also using hardware acceleration.

On low-end platforms, as well as for short messages, KT128 is roughly twice faster than the fastest FIPS 202 instance SHAKE128, and KT256 is roughly twice faster than SHAKE256.