From: provos Date: Thu, 13 Feb 1997 16:31:16 +0000 (+0000) Subject: password hashing algorithm using blowfish X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=6d84a8a155ebcb16a9347e393b3a25c1396681a9;p=openbsd password hashing algorithm using blowfish --- diff --git a/lib/libc/crypt/bcrypt.c b/lib/libc/crypt/bcrypt.c new file mode 100644 index 00000000000..66daa4e2df9 --- /dev/null +++ b/lib/libc/crypt/bcrypt.c @@ -0,0 +1,300 @@ +/* $OpenBSD: bcrypt.c,v 1.1 1997/02/13 16:31:16 provos Exp $ */ +/* + * Copyright 1997 Niels Provos + * + * Modification and redistribution in source and binary forms is + * permitted provided that due credit is given to the author and the + * OpenBSD project (for instance by leaving this copyright notice + * intact). + */ + +/* This password hashing algorithm was designed by David Mazieres + * and works as follows: + * + * 1. state := InitState () + * 2. state := ExpandKey (state, salt, password) 3. + * REPEAT rounds: + * state := ExpandKey (state, 0, salt) + * state := ExpandKey(state, 0, password) + * 4. ctext := "OpenBSDbcrypthashfunc" + * 5. REPEAT 64: + * ctext := Encrypt_ECB (state, ctext); + * 6. RETURN Concatenate (salt, ctext); + * + */ + +#ifdef TEST +#include +#endif + +#include +#include +#include +#include +#include +#include + +/* This implementation is adaptable to current computing power. + * You can have up to 2^31 rounds which should be enough for some + * time to come. + */ + +#define BCRYPT_VERSION '2' +#define BCRYPT_MAXSALT 16 /* Precomputation is just so nice */ +#define BCRYPT_BLOCKS 6 /* Ciphertext blocks */ +#define BCRYPT_MINROUNDS 16 /* we have log2(rounds) in salt */ + +char *bcrypt_gensalt __P((u_int8_t)); + +static void encode_salt __P((char *, u_int8_t *, u_int16_t, u_int8_t)); +static void encode_base64 __P((u_int8_t *, u_int8_t *, u_int16_t)); +static void decode_base64 __P((u_int8_t *, u_int16_t, u_int8_t *)); + +static char encrypted[_PASSWORD_LEN]; +static char gsalt[BCRYPT_MAXSALT * 4 / 3 + 1]; +static char error[] = ":"; + +const static u_int8_t Base64Code[] = +"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; + +const static u_int8_t index_64[128] = +{ + 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, + 255, 255, 255, 255, 255, 255, 0, 1, 54, 55, + 56, 57, 58, 59, 60, 61, 62, 63, 255, 255, + 255, 255, 255, 255, 255, 2, 3, 4, 5, 6, + 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, + 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, + 255, 255, 255, 255, 255, 255, 28, 29, 30, + 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, + 51, 52, 53, 255, 255, 255, 255, 255 +}; +#define CHAR64(c) ( (c) > 127 ? 255 : index_64[(c)]) + +static void +decode_base64(buffer, len, data) + u_int8_t *buffer; + u_int16_t len; + u_int8_t *data; +{ + u_int8_t *bp = buffer; + u_int8_t *p = data; + u_int8_t c1, c2, c3, c4; + while (bp < buffer + len) { + c1 = CHAR64(*p); + c2 = CHAR64(*(p + 1)); + + /* Invalid data */ + if (c1 == 255 || c2 == 255) + break; + + *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4); + if (bp >= buffer + len) + break; + + c3 = CHAR64(*(p + 2)); + if (c3 == 255) + break; + + *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2); + if (bp >= buffer + len) + break; + + c4 = CHAR64(*(p + 3)); + if (c4 == 255) + break; + *bp++ = ((c3 & 0x03) << 6) | c4; + + p += 4; + } +} + +static void +encode_salt(salt, csalt, clen, logr) + char *salt; + u_int8_t *csalt; + u_int16_t clen; + u_int8_t logr; +{ + salt[0] = '$'; + salt[1] = BCRYPT_VERSION; + salt[2] = '$'; + + snprintf(salt + 3, 4, "%2.2u$", logr); + + encode_base64((u_int8_t *) salt + 6, csalt, clen); +} +/* Generates a salt for this version of crypt. + Since versions may change. Keeping this here + seems sensible. + */ + +char * +bcrypt_gensalt(log_rounds) + u_int8_t log_rounds; +{ + u_int8_t csalt[BCRYPT_MAXSALT]; + u_int16_t i; + u_int32_t seed = 0; + (void) srandom((int) time((time_t *) NULL)); + for (i = 0; i < BCRYPT_MAXSALT; i++) { + if (i % 4 == 0) + seed = random(); + csalt[i] = seed & 0xff; + seed = seed >> 8; + } + + if (log_rounds < 4) + log_rounds = 4; + + encode_salt(gsalt, csalt, BCRYPT_MAXSALT, log_rounds); + return gsalt; +} +/* We handle $Vers$log2(NumRounds)$salt+passwd$ + i.e. $2$04$iwouldntknowwhattosayetKdJ6iFtacBqJdKe6aW7ou */ + +char * +bcrypt(key, salt) + char *key; + char *salt; +{ + blf_ctx state; + u_int32_t rounds, i, k; + u_int16_t j; + u_int8_t key_len, salt_len, logr; + u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OpenBSDbcrypthashfunc"; + u_int8_t csalt[BCRYPT_MAXSALT]; + u_int32_t cdata[BCRYPT_BLOCKS]; + /* Discard "$" identifier */ + salt++; + + if (*salt > BCRYPT_VERSION) { + /* How do I handle errors ? Return ':' */ + return error; + } + /* Discard version + "$" identifier */ + salt += 2; + + if (*(salt + 2) != '$') + /* Out of sync with passwd entry */ + return error; + + /* Computer power doesnt increase linear, 2^x should be fine */ + if ((rounds = (u_int32_t) 1 << (logr = atoi(salt))) < BCRYPT_MINROUNDS) + return error; + + /* Discard num rounds + "$" identifier */ + salt += 3; + + /* We dont want the base64 salt but the raw data */ + decode_base64(csalt, BCRYPT_MAXSALT, (u_int8_t *) salt); + salt_len = BCRYPT_MAXSALT; + key_len = strlen(key); + + /* Setting up S-Boxes and Subkeys */ + Blowfish_initstate(&state); + Blowfish_expandstate(&state, csalt, salt_len, + (u_int8_t *) key, key_len); + for (k = 0; k < rounds; k++) { + Blowfish_expand0state(&state, (u_int8_t *) key, key_len); + Blowfish_expand0state(&state, csalt, salt_len); + } + + /* This can be precomputed later */ + j = 0; + for (i = 0; i < BCRYPT_BLOCKS; i++) + cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j); + + /* Now do the encryption */ + for (k = 0; k < 64; k++) + blf_enc(&state, cdata, BCRYPT_BLOCKS / 2); + + for (i = 0; i < BCRYPT_BLOCKS; i++) { + ciphertext[4 * i + 3] = cdata[i] & 0xff; + cdata[i] = cdata[i] >> 8; + ciphertext[4 * i + 2] = cdata[i] & 0xff; + cdata[i] = cdata[i] >> 8; + ciphertext[4 * i + 1] = cdata[i] & 0xff; + cdata[i] = cdata[i] >> 8; + ciphertext[4 * i + 0] = cdata[i] & 0xff; + } + + + encrypted[0] = '$'; + encrypted[1] = BCRYPT_VERSION; + encrypted[2] = '$'; + + snprintf(encrypted + 3, 4, "%2.2u$", logr); + + encode_base64((u_int8_t *) encrypted + 6, csalt, BCRYPT_MAXSALT); + encode_base64((u_int8_t *) encrypted + strlen(encrypted), ciphertext, + 4 * BCRYPT_BLOCKS); + return encrypted; +} + +static void +encode_base64(buffer, data, len) + u_int8_t *buffer; + u_int8_t *data; + u_int16_t len; +{ + u_int8_t *bp = buffer; + u_int8_t *p = data; + u_int8_t c1, c2; + while (p < data + len) { + c1 = *p++; + *bp++ = Base64Code[(c1 >> 2)]; + c1 = (c1 & 0x03) << 4; + c2 = *p++; + if (p >= data + len) { + *bp++ = Base64Code[c1]; + break; + } + c1 |= (c2 >> 4) & 0x0f; + *bp++ = Base64Code[c1]; + c1 = (c2 & 0x0f) << 2; + c2 = *p++; + if (p >= data + len) { + *bp++ = Base64Code[c1]; + break; + } + c1 |= (c2 >> 6) & 0x03; + *bp++ = Base64Code[c1]; + *bp++ = Base64Code[c2 & 0x3f]; + } + *bp = '\0'; +} +#ifdef TEST +void +main() +{ + char blubber[73]; + char salt[100]; + char *p; + salt[0] = '$'; + salt[1] = BCRYPT_VERSION; + salt[2] = '$'; + + snprintf(salt + 3, 4, "%2.2u$", 5); + + printf("24 bytes of salt: "); + fgets(salt + 6, 94, stdin); + salt[99] = 0; + printf("72 bytes of password: "); + fpurge(stdin); + fgets(blubber, 73, stdin); + blubber[72] = 0; + + p = crypt(blubber, salt); + printf("Passwd entry: %s\n\n", p); + + p = bcrypt_gensalt(5); + printf("Generated salt: %s\n", p); + p = crypt(blubber, p); + printf("Passwd entry: %s\n", p); +} +#endif