TEA\uff08Tiny Encryption Algorithm\uff09\u662f\u4e00\u7c7b\u8f7b\u91cf\u7ea7\u5206\u7ec4\u52a0\u5bc6\u7b97\u6cd5\uff0c\u7279\u70b9\u662f\u7ed3\u6784\u7b80\u5355\u3001\u4ee3\u7801\u91cf\u5c0f\u3001\u5b9e\u73b0\u65b9\u4fbf\u3002
\u5b83\u7684\u5bb6\u65cf\u4e3b\u8981\u5305\u62ec\uff1a<\/p>\n\n\n\n
\u5728 CTF \u9006\u5411\u9898\u4e2d\uff0cTEA \u5bb6\u65cf\u5e38\u88ab\u7528\u6765\uff1a<\/p>\n\n\n\n
TEA \u5bb6\u65cf\u4e4b\u6240\u4ee5\u5e38\u89c1\uff0c\u662f\u56e0\u4e3a\u5b83\u7684\u4ee3\u7801\u975e\u5e38\u77ed\uff0c\u51fa\u9898\u4eba\u6539\u8d77\u6765\u65b9\u4fbf\uff1b\u4f46\u540c\u65f6\u5b83\u53c8\u6709\u660e\u663e\u7684\u7ed3\u6784\u7279\u5f81\uff0c\u53ea\u8981\u638c\u63e1\u8bc6\u522b\u65b9\u6cd5\uff0c\u9006\u5411\u6062\u590d\u5e76\u4e0d\u96be\u3002<\/p>\n\n\n\n
TEA \u7684\u6807\u51c6\u53c2\u6570\u5982\u4e0b\uff1a<\/p>\n\n\n\n
0x9E3779B9<\/code><\/li>\n<\/ul>\n\n\n\n\u8fd9\u91cc\u7684 delta<\/code> \u6765\u6e90\u4e8e\u9ec4\u91d1\u5206\u5272\u76f8\u5173\u5e38\u6570\uff0c\u7528\u4e8e\u6253\u7834\u8f6e\u51fd\u6570\u7684\u5bf9\u79f0\u6027\u3002<\/p>\n\n\n\n\u901a\u5e38\u628a 64 bit \u660e\u6587\u62c6\u6210\u4e24\u4e2a 32 bit\uff1a<\/p>\n\n\n\n
\nv0<\/code><\/li>\n\n\n\nv1<\/code><\/li>\n<\/ul>\n\n\n\n128 bit \u5bc6\u94a5\u62c6\u6210\u56db\u4e2a 32 bit\uff1a<\/p>\n\n\n\n
\nk0<\/code><\/li>\n\n\n\nk1<\/code><\/li>\n\n\n\nk2<\/code><\/li>\n\n\n\nk3<\/code><\/li>\n<\/ul>\n\n\n\n2.2 \u6807\u51c6 TEA \u52a0\u5bc6\u516c\u5f0f<\/h3>\n\n\n\n
TEA \u6bcf\u8f6e\u90fd\u66f4\u65b0 sum<\/code>\uff0c\u7136\u540e\u4ea4\u66ff\u66f4\u65b0\u5de6\u53f3\u4e24\u90e8\u5206\u3002<\/p>\n\n\n\n\u52a0\u5bc6\u4f2a\u4ee3\u7801\uff1a<\/p>\n\n\n\n
sum = 0;
for (i = 0; i < 32; i++) {
sum += delta;
v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
}<\/pre>\n\n\n\n\u89e3\u5bc6\u65f6\u5b8c\u5168\u53cd\u8fc7\u6765\uff1a<\/p>\n\n\n\n
sum = delta * 32;
for (i = 0; i < 32; i++) {
v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
sum -= delta;
}<\/pre>\n\n\n\n3. XTEA\uff1aTEA \u7684\u6269\u5c55\u7248\u672c<\/h2>\n\n\n\n
XTEA\uff08eXtended TEA\uff09\u662f\u5bf9 TEA \u7684\u6539\u8fdb\u7248\u672c\uff0c\u4e3b\u8981\u662f\u4fee\u6539\u4e86\u8f6e\u51fd\u6570\u548c key \u7684\u9009\u53d6\u65b9\u5f0f\u3002<\/p>\n\n\n\n
\u5b83\u548c TEA \u6700\u660e\u663e\u7684\u533a\u522b\u5728\u4e8e\uff1a<\/p>\n\n\n\n
\n- key \u4e0d\u518d\u56fa\u5b9a\u5199\u6b7b\u6210
(k0, k1)<\/code> \u548c (k2, k3)<\/code><\/li>\n\n\n\n- \u800c\u662f\u901a\u8fc7
sum<\/code> \u7684\u4f4e\u4f4d\u548c\u9ad8\u4f4d\u52a8\u6001\u9009\u62e9 key \u4e0b\u6807<\/li>\n<\/ul>\n\n\n\n\u6807\u51c6 XTEA \u5e38\u89c1\u5199\u6cd5\uff1a<\/p>\n\n\n\n
sum = 0;
for (i = 0; i < 32; i++) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
}<\/pre>\n\n\n\n\u89e3\u5bc6\uff1a<\/p>\n\n\n\n
sum = delta * 32;
for (i = 0; i < 32; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
}<\/pre>\n\n\n\nXTEA \u5728\u9006\u5411\u4e2d\u7684\u8bc6\u522b\u70b9<\/h3>\n\n\n\n
\u5982\u679c\u4f60\u5728\u4f2a\u4ee3\u7801\u91cc\u770b\u89c1\uff1a<\/p>\n\n\n\n
\nsum & 3<\/code><\/li>\n\n\n\n(sum >> 11) & 3<\/code><\/li>\n\n\n\n((x << 4) ^ (x >> 5)) + x<\/code><\/li>\n<\/ul>\n\n\n\n\u90a3\u5927\u6982\u7387\u5c31\u662f XTEA<\/strong>\uff0c\u4e0d\u662f\u666e\u901a TEA\u3002<\/p>\n\n\n\n4. XXTEA\uff1a\u53ef\u53d8\u957f\u5ea6\u5757\u52a0\u5bc6<\/h2>\n\n\n\n
XXTEA \u548c TEA \/ XTEA \u6700\u5927\u7684\u4e0d\u540c\u5728\u4e8e\uff1a<\/p>\n\n\n\n
\n- \u5b83\u4e0d\u518d\u56fa\u5b9a\u53ea\u5904\u7406\u4e24\u4e2a 32 bit<\/li>\n\n\n\n
- \u5b83\u53ef\u4ee5\u5904\u7406\u591a\u4e2a 32 bit \u5355\u5143\u7ec4\u6210\u7684\u6570\u7ec4<\/li>\n<\/ul>\n\n\n\n
\u6240\u4ee5 XXTEA \u975e\u5e38\u9002\u5408\u5728 CTF \u4e2d\u7528\u6765\u52a0\u5bc6\u6574\u6bb5\u5b57\u7b26\u4e32\u3001\u6574\u5757\u6570\u636e\u3002<\/p>\n\n\n\n
\u5b83\u7684\u6838\u5fc3\u601d\u8def\u662f\u8ba9\u4e00\u4e2a\u6570\u7ec4\u4e2d\u7684\u5404\u4e2a\u5143\u7d20\u4e92\u76f8\u5f71\u54cd\uff0c\u8f6e\u51fd\u6570\u66f4\u590d\u6742\uff0c\u5e38\u89c1\u4ee3\u7801\u91cc\u4f1a\u770b\u5230\uff1a<\/p>\n\n\n\n
\nn > 1<\/code><\/li>\n\n\n\nrounds = 6 + 52 \/ n<\/code><\/li>\n\n\n\ne = (sum >> 2) & 3<\/code><\/li>\n\n\n\nMX<\/code> \u5b8f<\/li>\n<\/ul>\n\n\n\n\u7ecf\u5178 XXTEA \u4ee3\u7801\u91cc\u6700\u5178\u578b\u7684\u7279\u5f81\u5c31\u662f\uff1a<\/p>\n\n\n\n
z = v[p] += MX;
y = v[p + 1];<\/pre>\n\n\n\n\u6216\u8005\u672b\u5c3e\u8fd8\u6709\uff1a<\/p>\n\n\n\n
z = v[n - 1] += MX;<\/pre>\n\n\n\nXXTEA \u7684\u9006\u5411\u7279\u5f81\u975e\u5e38\u5f3a<\/h3>\n\n\n\n
\u53ea\u8981\u4f60\u770b\u5230\u4e0b\u9762\u8fd9\u4e9b\u4e1c\u897f\u540c\u65f6\u51fa\u73b0\uff0c\u57fa\u672c\u5c31\u53ef\u4ee5\u5224\u5b9a\u662f XXTEA\uff1a<\/p>\n\n\n\n
\n6 + 52 \/ n<\/code><\/li>\n\n\n\n0x9E3779B9<\/code><\/li>\n\n\n\n- \u6570\u7ec4\u5faa\u73af\u66f4\u65b0<\/li>\n\n\n\n
((z>>5^y<<2) + (y>>3^z<<4)) ^ ((sum^y) + (k[(p&3)^e] ^ z))<\/code><\/li>\n<\/ul>\n\n\n\nimport struct\n\nMASK = 0xffffffff\nDELTA = 0x9E3779B9\n\n\ndef _mx(z, y, sum_, k, p, e):\n return ((((z >> 5) ^ (y << 2)) + ((y >> 3) ^ (z << 4))) ^ ((sum_ ^ y) + (k[(p & 3) ^ e] ^ z))) & MASK\n\n\ndef xxtea_encrypt_u32(v, k):\n n = len(v)\n if n < 2:\n return v[:]\n\n rounds = 6 + 52 \/\/ n\n sum_ = 0\n z = v[n - 1]\n\n v = v[:]\n while rounds > 0:\n rounds -= 1\n sum_ = (sum_ + DELTA) & MASK\n e = (sum_ >> 2) & 3\n for p in range(n - 1):\n y = v[p + 1]\n v[p] = (v[p] + _mx(z, y, sum_, k, p, e)) & MASK\n z = v[p]\n y = v[0]\n v[n - 1] = (v[n - 1] + _mx(z, y, sum_, k, n - 1, e)) & MASK\n z = v[n - 1]\n return v\n\n\ndef xxtea_decrypt_u32(v, k):\n n = len(v)\n if n < 2:\n return v[:]\n\n rounds = 6 + 52 \/\/ n\n sum_ = (rounds * DELTA) & MASK\n v = v[:]\n\n while sum_ != 0:\n e = (sum_ >> 2) & 3\n y = v[0]\n for p in range(n - 1, 0, -1):\n z = v[p - 1]\n v[p] = (v[p] - _mx(z, y, sum_, k, p, e)) & MASK\n y = v[p]\n z = v[n - 1]\n v[0] = (v[0] - _mx(z, y, sum_, k, 0, e)) & MASK\n y = v[0]\n sum_ = (sum_ - DELTA) & MASK\n return v\n\n\ndef bytes_to_u32_list(data):\n pad = (4 - len(data) % 4) % 4\n data = data + b'\\x00' * pad\n return list(struct.unpack('<{}I'.format(len(data) \/\/ 4), data)), len(data) - pad\n\n\ndef u32_list_to_bytes(v):\n return struct.pack('<{}I'.format(len(v)), *v)\n\n\ndef fix_key(key_bytes):\n if len(key_bytes) < 16:\n key_bytes = key_bytes.ljust(16, b'\\x00')\n elif len(key_bytes) > 16:\n key_bytes = key_bytes[:16]\n return list(struct.unpack('<4I', key_bytes))\n\n\ndef xxtea_encrypt(data, key_bytes):\n v, orig_len = bytes_to_u32_list(data + struct.pack('<I', len(data)))\n k = fix_key(key_bytes)\n enc = xxtea_encrypt_u32(v, k)\n return u32_list_to_bytes(enc)\n\n\ndef xxtea_decrypt(data, key_bytes):\n v = list(struct.unpack('<{}I'.format(len(data) \/\/ 4), data))\n k = fix_key(key_bytes)\n dec = xxtea_decrypt_u32(v, k)\n raw = u32_list_to_bytes(dec)\n orig_len = struct.unpack('<I', raw[-4:])[0]\n return raw[:orig_len]\n\n\nif __name__ == \"__main__\":\n key = b\"1234567890abcdef\"\n data = b\"hello xxtea reverse\"\n\n enc = xxtea_encrypt(data, key)\n dec = xxtea_decrypt(enc, key)\n\n print(\"enc =\", enc.hex())\n print(\"dec =\", dec)<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"1. TEA\u5bb6\u65cf\u7b80\u4ecb TEA\uff08Tiny Encryption Algorithm\uff09\u662f\u4e00\u7c7b\u8f7b\u91cf\u7ea7\u5206\u7ec4\u52a0\u5bc6\u7b97\u6cd5\uff0c\u7279\u70b9\u662f\u7ed3\u6784\u7b80\u5355\u3001\u4ee3\u7801\u91cf …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-189","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/posts\/189","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/comments?post=189"}],"version-history":[{"count":1,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/posts\/189\/revisions"}],"predecessor-version":[{"id":190,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/posts\/189\/revisions\/190"}],"wp:attachment":[{"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/media?parent=189"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/categories?post=189"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sherlock666.cn\/index.php\/wp-json\/wp\/v2\/tags?post=189"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}