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Returns a Keccak hash of the supplied object or file.


keccak(x, bits = 256L, convert = TRUE, file)



object to hash. A character string or raw vector (without attributes) is hashed 'as is'. All other objects are stream hashed using R serialization (but without allocation of the serialized object).


[default 256L] output size of the returned hash. Must be one of 224, 256, 384 or 512.


[default TRUE] if TRUE, the hash is converted to its hex representation as a character string, if FALSE, output directly as a raw vector, or if NA, a vector of (32-bit) integer values.


character file name / path. If specified, 'x' is ignored. The file is stream hashed, thus capable of handling files larger than memory.


A character string, raw or integer vector depending on 'convert'.

R Serialization Stream Hashing

Where this is used, serialization is always version 3 big-endian represenation and the headers (containing R version and native encoding information) are skipped to ensure portability across platforms.


Keccak is the underlying algorithm for SHA-3, and is identical apart from the value of the padding parameter.

The Keccak algorithm was designed by G. Bertoni, J. Daemen, M. Peeters and G. Van Assche.

This implementation is based on one by 'The Mbed TLS Contributors' under the 'Mbed TLS' Trusted Firmware Project at


# Keccak-256 hash as character string:
keccak("secret base")
#> [1] "3fc6092bbec5a434a9933b486a89fa466c1ca013d1e37ab4348ce3764f3463d1"

# Keccak-256 hash as raw vector:
keccak("secret base", convert = FALSE)
#>  [1] 3f c6 09 2b be c5 a4 34 a9 93 3b 48 6a 89 fa 46 6c 1c a0 13 d1 e3 7a b4 34
#> [26] 8c e3 76 4f 34 63 d1

# Keccak-224 hash as character string:
keccak("secret base", bits = 224)
#> [1] "1ddaa7776f138ff5bba898ca7530410a52d09da412c4276bda0682a8"

# Keccak-384 hash as character string:
keccak("secret base", bits = 384)
#> [1] "c82bae24175676028e44aa08b9e2424311847adb0b071c68c7ea47edf049b0e935ddd2fc7c499333bccc08c7eb7b1203"

# Keccak-512 hash as character string:
keccak("secret base", bits = 512)
#> [1] "38297e891d9118e4cf6ff5ba6d6de8c2c3bfa790b425848da7b1d8dffcb4a6a3ca2e32ca0a66f36ce2882786ce2299642de8ffd3bae3b51a1ee145fad555a9d8"

# Keccak-256 hash a file:
file <- tempfile(); cat("secret base", file = file)
keccak(file = file)
#> [1] "3fc6092bbec5a434a9933b486a89fa466c1ca013d1e37ab4348ce3764f3463d1"