crypto

A cryptography library for the Odin language

Supported

This library offers various algorithms implemented in Odin. Please see the chart below for some of the options.

Hashing algorithms

Algorithm
BLAKE2B	✔️
BLAKE2S	✔️
SHA-2	✔️
SHA-3	✔️
SHAKE	✔️
SM3	✔️
legacy/Keccak	✔️
legacy/MD5	✔️
legacy/SHA-1	✔️

High level API

Each hash algorithm contains a procedure group named hash, or if the algorithm provides more than one digest size hash_<size>*. Included in these groups are six procedures.

hash_string - Hash a given string and return the computed hash. Just calls hash_bytes internally
hash_bytes - Hash a given byte slice and return the computed hash
hash_string_to_buffer - Hash a given string and put the computed hash in the second proc parameter. Just calls hash_bytes_to_buffer internally
hash_bytes_to_buffer - Hash a given string and put the computed hash in the second proc parameter. The destination buffer has to be at least as big as the digest size of the hash
hash_stream - Takes a stream from io.Stream and returns the computed hash from it
hash_file - Takes a file handle and returns the computed hash from it. A second optional boolean parameter controls if the file is streamed (this is the default) or read at once (set to true)

* On some algorithms there is another part to the name, since they might offer control about additional parameters. For instance, SHA-2 offers different sizes. Computing a 512-bit hash is therefore achieved by calling sha2.hash_512(...).

Low level API

The above mentioned procedures internally call three procedures: init, update and final. You may also directly call them, if you wish.

Example

package crypto_example

// Import the desired package
import "core:crypto/blake2b"

main :: proc() {
    input := "foo"

    // Compute the hash, using the high level API
    computed_hash := blake2b.hash(input)

    // Variant that takes a destination buffer, instead of returning the computed hash
    hash := make([]byte, sha2.DIGEST_SIZE) // @note: Destination buffer has to be at least as big as the digest size of the hash
    blake2b.hash(input, hash[:])

    // Compute the hash, using the low level API
    ctx: blake2b.Context
    computed_hash_low: [blake2b.DIGEST_SIZE]byte
    blake2b.init(&ctx)
    blake2b.update(&ctx, transmute([]byte)input)
    blake2b.final(&ctx, computed_hash_low[:])
}

For example uses of all available algorithms, please see the tests within tests/core/crypto.

Implementation considerations

The crypto packages are not thread-safe.
Best-effort is make to mitigate timing side-channels on reasonable architectures. Architectures that are known to be unreasonable include but are not limited to i386, i486, and WebAssembly.
Some but not all of the packages attempt to santize sensitive data, however this is not done consistently through the library at the moment. As Thomas Pornin puts it "In general, such memory cleansing is a fool's quest."
All of these packages have not received independent third party review.

License

This library is made available under the BSD-3 license.

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