X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=libtomcrypt%2Fsrc%2Fprngs%2Frc4.c;fp=libtomcrypt%2Fsrc%2Fprngs%2Frc4.c;h=e2aa92175e76bc6255fc3d5ab5729b2ca12e610a;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage diff --git a/libtomcrypt/src/prngs/rc4.c b/libtomcrypt/src/prngs/rc4.c new file mode 100644 index 0000000..e2aa921 --- /dev/null +++ b/libtomcrypt/src/prngs/rc4.c @@ -0,0 +1,250 @@ +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + */ +#include "tomcrypt.h" + +/** + @file prngs/rc4.c + RC4 PRNG, Tom St Denis +*/ + +#ifdef LTC_RC4 + +const struct ltc_prng_descriptor rc4_desc = +{ + "rc4", + 32, + &rc4_start, + &rc4_add_entropy, + &rc4_ready, + &rc4_read, + &rc4_done, + &rc4_export, + &rc4_import, + &rc4_test +}; + +/** + Start the PRNG + @param prng [out] The PRNG state to initialize + @return CRYPT_OK if successful +*/ +int rc4_start(prng_state *prng) +{ + LTC_ARGCHK(prng != NULL); + prng->ready = 0; + /* set entropy (key) size to zero */ + prng->rc4.s.x = 0; + /* clear entropy (key) buffer */ + XMEMSET(&prng->rc4.s.buf, 0, sizeof(prng->rc4.s.buf)); + LTC_MUTEX_INIT(&prng->lock) + return CRYPT_OK; +} + +/** + Add entropy to the PRNG state + @param in The data to add + @param inlen Length of the data to add + @param prng PRNG state to update + @return CRYPT_OK if successful +*/ +int rc4_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng) +{ + unsigned char buf[256]; + unsigned long i; + int err; + + LTC_ARGCHK(prng != NULL); + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(inlen > 0); + + LTC_MUTEX_LOCK(&prng->lock); + if (prng->ready) { + /* rc4_ready() was already called, do "rekey" operation */ + if ((err = rc4_stream_keystream(&prng->rc4.s, buf, sizeof(buf))) != CRYPT_OK) goto LBL_UNLOCK; + for(i = 0; i < inlen; i++) buf[i % sizeof(buf)] ^= in[i]; + /* initialize RC4 */ + if ((err = rc4_stream_setup(&prng->rc4.s, buf, sizeof(buf))) != CRYPT_OK) goto LBL_UNLOCK; + /* drop first 3072 bytes - https://en.wikipedia.org/wiki/RC4#Fluhrer.2C_Mantin_and_Shamir_attack */ + for (i = 0; i < 12; i++) rc4_stream_keystream(&prng->rc4.s, buf, sizeof(buf)); + zeromem(buf, sizeof(buf)); + } + else { + /* rc4_ready() was not called yet, add entropy to the buffer */ + while (inlen--) prng->rc4.s.buf[prng->rc4.s.x++ % sizeof(prng->rc4.s.buf)] ^= *in++; + } + err = CRYPT_OK; +LBL_UNLOCK: + LTC_MUTEX_UNLOCK(&prng->lock); + return err; +} + +/** + Make the PRNG ready to read from + @param prng The PRNG to make active + @return CRYPT_OK if successful +*/ +int rc4_ready(prng_state *prng) +{ + unsigned char buf[256] = { 0 }; + unsigned long len; + int err, i; + + LTC_ARGCHK(prng != NULL); + + LTC_MUTEX_LOCK(&prng->lock); + if (prng->ready) { err = CRYPT_OK; goto LBL_UNLOCK; } + XMEMCPY(buf, prng->rc4.s.buf, sizeof(buf)); + /* initialize RC4 */ + len = MIN(prng->rc4.s.x, 256); /* TODO: we can perhaps always use all 256 bytes */ + if ((err = rc4_stream_setup(&prng->rc4.s, buf, len)) != CRYPT_OK) goto LBL_UNLOCK; + /* drop first 3072 bytes - https://en.wikipedia.org/wiki/RC4#Fluhrer.2C_Mantin_and_Shamir_attack */ + for (i = 0; i < 12; i++) rc4_stream_keystream(&prng->rc4.s, buf, sizeof(buf)); + prng->ready = 1; +LBL_UNLOCK: + LTC_MUTEX_UNLOCK(&prng->lock); + return err; +} + +/** + Read from the PRNG + @param out Destination + @param outlen Length of output + @param prng The active PRNG to read from + @return Number of octets read +*/ +unsigned long rc4_read(unsigned char *out, unsigned long outlen, prng_state *prng) +{ + if (outlen == 0 || prng == NULL || out == NULL) return 0; + LTC_MUTEX_LOCK(&prng->lock); + if (!prng->ready) { outlen = 0; goto LBL_UNLOCK; } + if (rc4_stream_keystream(&prng->rc4.s, out, outlen) != CRYPT_OK) outlen = 0; +LBL_UNLOCK: + LTC_MUTEX_UNLOCK(&prng->lock); + return outlen; +} + +/** + Terminate the PRNG + @param prng The PRNG to terminate + @return CRYPT_OK if successful +*/ +int rc4_done(prng_state *prng) +{ + int err; + LTC_ARGCHK(prng != NULL); + LTC_MUTEX_LOCK(&prng->lock); + prng->ready = 0; + err = rc4_stream_done(&prng->rc4.s); + LTC_MUTEX_UNLOCK(&prng->lock); + LTC_MUTEX_DESTROY(&prng->lock); + return err; +} + +/** + Export the PRNG state + @param out [out] Destination + @param outlen [in/out] Max size and resulting size of the state + @param prng The PRNG to export + @return CRYPT_OK if successful +*/ +int rc4_export(unsigned char *out, unsigned long *outlen, prng_state *prng) +{ + unsigned long len = rc4_desc.export_size; + + LTC_ARGCHK(prng != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + + if (*outlen < len) { + *outlen = len; + return CRYPT_BUFFER_OVERFLOW; + } + + if (rc4_read(out, len, prng) != len) { + return CRYPT_ERROR_READPRNG; + } + + *outlen = len; + return CRYPT_OK; +} + +/** + Import a PRNG state + @param in The PRNG state + @param inlen Size of the state + @param prng The PRNG to import + @return CRYPT_OK if successful +*/ +int rc4_import(const unsigned char *in, unsigned long inlen, prng_state *prng) +{ + int err; + + LTC_ARGCHK(prng != NULL); + LTC_ARGCHK(in != NULL); + if (inlen < (unsigned long)rc4_desc.export_size) return CRYPT_INVALID_ARG; + + if ((err = rc4_start(prng)) != CRYPT_OK) return err; + if ((err = rc4_add_entropy(in, inlen, prng)) != CRYPT_OK) return err; + return CRYPT_OK; +} + +/** + PRNG self-test + @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled +*/ +int rc4_test(void) +{ +#ifndef LTC_TEST + return CRYPT_NOP; +#else + prng_state st; + unsigned char en[] = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, + 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, + 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, + 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, + 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32 }; + unsigned char dmp[500]; + unsigned long dmplen = sizeof(dmp); + unsigned char out[1000]; + unsigned char t1[] = { 0xE0, 0x4D, 0x9A, 0xF6, 0xA8, 0x9D, 0x77, 0x53, 0xAE, 0x09 }; + unsigned char t2[] = { 0xEF, 0x80, 0xA2, 0xE6, 0x50, 0x91, 0xF3, 0x17, 0x4A, 0x8A }; + unsigned char t3[] = { 0x4B, 0xD6, 0x5C, 0x67, 0x99, 0x03, 0x56, 0x12, 0x80, 0x48 }; + int err; + + if ((err = rc4_start(&st)) != CRYPT_OK) return err; + /* add entropy to uninitialized prng */ + if ((err = rc4_add_entropy(en, sizeof(en), &st)) != CRYPT_OK) return err; + if ((err = rc4_ready(&st)) != CRYPT_OK) return err; + if (rc4_read(out, 10, &st) != 10) return CRYPT_ERROR_READPRNG; /* 10 bytes for testing */ + if (compare_testvector(out, 10, t1, sizeof(t1), "RC4-PRNG", 1)) return CRYPT_FAIL_TESTVECTOR; + if (rc4_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */ + /* add entropy to already initialized prng */ + if ((err = rc4_add_entropy(en, sizeof(en), &st)) != CRYPT_OK) return err; + if (rc4_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */ + if ((err = rc4_export(dmp, &dmplen, &st)) != CRYPT_OK) return err; + if (rc4_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */ + if (rc4_read(out, 10, &st) != 10) return CRYPT_ERROR_READPRNG; /* 10 bytes for testing */ + if (compare_testvector(out, 10, t2, sizeof(t2), "RC4-PRNG", 2)) return CRYPT_FAIL_TESTVECTOR; + if ((err = rc4_done(&st)) != CRYPT_OK) return err; + if ((err = rc4_import(dmp, dmplen, &st)) != CRYPT_OK) return err; + if ((err = rc4_ready(&st)) != CRYPT_OK) return err; + if (rc4_read(out, 500, &st) != 500) return CRYPT_ERROR_READPRNG; /* skip 500 bytes */ + if (rc4_read(out, 10, &st) != 10) return CRYPT_ERROR_READPRNG; /* 10 bytes for testing */ + if (compare_testvector(out, 10, t3, sizeof(t3), "RC4-PRNG", 3)) return CRYPT_FAIL_TESTVECTOR; + if ((err = rc4_done(&st)) != CRYPT_OK) return err; + + return CRYPT_OK; +#endif +} + +#endif + +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */