/**
* Synchronous SHA-256 / HMAC / HKDF so markdown rendering (which is synchronous all the way down through
* markdown-it and the HTML sanitizer) can sign image proxy URLs without becoming async. WebCrypto is used
* everywhere else; this is a textbook FIPS 180-4 implementation for short inputs only.
*/
const encoder = new TextEncoder();
const BLOCK_BYTES = 64;
const DIGEST_BYTES = 32;
const WORD_BITS = 32;
const BYTE_BITS = 8;
const LENGTH_FIELD_BYTES = 8;
const PADDING_BYTE = 0x80;
const IPAD = 0x36;
const OPAD = 0x5c;
const ROUNDS = 64;
const SCHEDULE_WORDS = 64;
const BLOCK_WORDS = 16;
const HEX_RADIX = 16;
const BYTE_MASK = 0xff;
const INITIAL_STATE = [
0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
] as const;
const ROUND_CONSTANTS = [
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98,
0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8,
0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819,
0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7,
0xc67178f2,
] as const;
function rotr(value: number, bits: number): number {
return (value >>> bits) | (value << (WORD_BITS - bits));
}