以下是JavaScript中实现SHA-256加密算法的详细代码：
// 将字符串转成UTF-8编码的字节数组function stringToUtf8ByteArray(str) {const utf8 = unescape(encodeURIComponent(str));const byteArray = [];for (let i = 0; i < utf8.length; i++) {byteArray.push(utf8.charCodeAt(i));}return byteArray;}// 将字节数组转成十六进制字符串function byteArrayToHexString(byteArray) {const hexString = [];for (let i = 0; i < byteArray.length; i++) {hexString.push(('0' + (byteArray[i] & 0xFF).toString(16)).slice(-2));}return hexString.join('');}// 右移位运算function rotateRight(n, x) {return (x >>> n) | (x << (32 - n));}// SHA-256加密算法function sha256(str) {const byteArray = stringToUtf8ByteArray(str);const k = [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];const h = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19];const paddedByteArray = [...byteArray];paddedByteArray.push(0x80);const messageLength = paddedByteArray.length * 8;const paddingSize = (448 - (messageLength + 8) % 512 + 512) % 512;for (let i = 0; i < paddingSize / 8; i++) {paddedByteArray.push(0x00);}for (let i = 0; i < 8; i++) {paddedByteArray.push((messageLength >>> (56 - i * 8)) & 0xFF);}const chunks = [];for (let i = 0; i < paddedByteArray.length /