Struct HmacSha256 

pub struct HmacSha256<'a>(/* private fields */);

Circuit for HMAC-SHA256.

HMAC is computed as: HMAC(key, message) = H((key ⊕ opad) || H((key ⊕ ipad) || message))

Where:

• H is SHA-256
• ipad is 0x36 repeated for the block size (512 bits)
• opad is 0x5c repeated for the block size (512 bits)
• key is padded with zeros to the block size if shorter, or hashed if longer

This implementation uses a 512-bit key (the SHA-256 block size) to avoid needing to hash long keys. For shorter keys, pad with zeros to 512 bits before passing to this circuit.

Implementations

impl<'a> HmacSha256<'a>

pub fn new() -> Self

Create a new HmacSha256 circuit.

Trait Implementations

impl<'a, F: FancyBinary> Circuit<F> for HmacSha256<'a>

where F::Item: 'a,

type Input = (&'a [<F as Fancy>::Item; 512], &'a [<F as Fancy>::Item])

A 512-bit key and a variable-length message.

type Output = [<F as Fancy>::Item; 256]

A 256-bit HMAC tag.

fn execute( &self, backend: &mut F, inputs: Self::Input, channel: &mut Channel<'_>, ) -> Result<Self::Output>

Execute a circuit on a given Fancy backend using the provided inputs.

impl<'a> Default for HmacSha256<'a>

fn default() -> HmacSha256<'a>

Returns the “default value” for a type.