62 lines
1.8 KiB
Plaintext
62 lines
1.8 KiB
Plaintext
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---
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title: "Cryptographic Hashing in R"
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date: "`r Sys.Date()`"
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vignette: >
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%\VignetteEngine{knitr::rmarkdown}
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%\VignetteIndexEntry{Cryptographic Hashing in R}
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\usepackage[utf8]{inputenc}
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output:
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html_document
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---
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```{r, echo = FALSE, message = FALSE}
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knitr::opts_chunk$set(comment = "")
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library(openssl)
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```
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The functions `sha1`, `sha256`, `sha512`, `md4`, `md5` and `ripemd160` bind to the respective [digest functions](https://docs.openssl.org/1.1.1/man1/openssl-dgst/) in OpenSSL's libcrypto. Both binary and string inputs are supported and the output type will match the input type.
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```{r}
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md5("foo")
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md5(charToRaw("foo"))
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```
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Functions are fully vectorized for the case of character vectors: a vector with n strings will return n hashes.
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```{r}
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# Vectorized for strings
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md5(c("foo", "bar", "baz"))
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```
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Besides character and raw vectors we can pass a connection object (e.g. a file, socket or url). In this case the function will stream-hash the binary contents of the connection.
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```{r}
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# Stream-hash a file
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myfile <- system.file("CITATION")
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md5(file(myfile))
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```
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Same for URLs. The hash of the [`R-installer.exe`](https://cran.r-project.org/bin/windows/base/old/4.0.0/R-4.0.0-win.exe) below should match the one in [`md5sum.txt`](https://cran.r-project.org/bin/windows/base/old/4.0.0/md5sum.txt)
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```{r eval=FALSE}
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# Stream-hash from a network connection
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as.character(md5(url("https://cran.r-project.org/bin/windows/base/old/4.0.0/R-4.0.0-win.exe")))
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# Compare
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readLines('https://cran.r-project.org/bin/windows/base/old/4.0.0/md5sum.txt')
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```
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## Compare to digest
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Similar functionality is also available in the **digest** package, but with a slightly different interface:
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```{r}
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# Compare to digest
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library(digest)
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digest("foo", "md5", serialize = FALSE)
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# Other way around
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digest(cars, skip = 0)
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md5(serialize(cars, NULL))
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```
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