svn commit: r344714 - head/sys/crypto/chacha20
Conrad Meyer
cem at FreeBSD.org
Fri Mar 1 23:30:24 UTC 2019
Author: cem
Date: Fri Mar 1 23:30:23 2019
New Revision: 344714
URL: https://svnweb.freebsd.org/changeset/base/344714
Log:
Embedded chacha: Add 0-bit iv + 128-bit counter mode
This mode might be suitable for a Fortuna keystream primitive.
Reviewed by: markm
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D19410
Modified:
head/sys/crypto/chacha20/chacha.c
head/sys/crypto/chacha20/chacha.h
Modified: head/sys/crypto/chacha20/chacha.c
==============================================================================
--- head/sys/crypto/chacha20/chacha.c Fri Mar 1 22:51:45 2019 (r344713)
+++ head/sys/crypto/chacha20/chacha.c Fri Mar 1 23:30:23 2019 (r344714)
@@ -84,13 +84,33 @@ chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits)
LOCAL void
chacha_ivsetup(chacha_ctx *x, const u8 *iv, const u8 *counter)
{
+#ifndef CHACHA_NONCE0_CTR128
x->input[12] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 0);
x->input[13] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 4);
x->input[14] = U8TO32_LITTLE(iv + 0);
x->input[15] = U8TO32_LITTLE(iv + 4);
+#else
+ // CHACHA_STATELEN
+ (void)iv;
+ x->input[12] = U8TO32_LITTLE(counter + 0);
+ x->input[13] = U8TO32_LITTLE(counter + 4);
+ x->input[14] = U8TO32_LITTLE(counter + 8);
+ x->input[15] = U8TO32_LITTLE(counter + 12);
+#endif
}
+#ifdef CHACHA_NONCE0_CTR128
LOCAL void
+chacha_ctrsave(const chacha_ctx *x, u8 *counter)
+{
+ U32TO8_LITTLE(counter + 0, x->input[12]);
+ U32TO8_LITTLE(counter + 4, x->input[13]);
+ U32TO8_LITTLE(counter + 8, x->input[14]);
+ U32TO8_LITTLE(counter + 12, x->input[15]);
+}
+#endif
+
+LOCAL void
chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes)
{
u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
@@ -192,7 +212,16 @@ chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u
j12 = PLUSONE(j12);
if (!j12) {
j13 = PLUSONE(j13);
+#ifndef CHACHA_NONCE0_CTR128
/* stopping at 2^70 bytes per nonce is user's responsibility */
+#else
+ if (!j13) {
+ j14 = PLUSONE(j14);
+ if (!j14) {
+ j15 = PLUSONE(j15);
+ }
+ }
+#endif
}
U32TO8_LITTLE(c + 0,x0);
@@ -218,6 +247,10 @@ chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u
}
x->input[12] = j12;
x->input[13] = j13;
+#ifdef CHACHA_NONCE0_CTR128
+ x->input[14] = j14;
+ x->input[15] = j15;
+#endif
return;
}
bytes -= 64;
Modified: head/sys/crypto/chacha20/chacha.h
==============================================================================
--- head/sys/crypto/chacha20/chacha.h Fri Mar 1 22:51:45 2019 (r344713)
+++ head/sys/crypto/chacha20/chacha.h Fri Mar 1 23:30:23 2019 (r344714)
@@ -26,10 +26,19 @@ Public domain.
#define LOCAL
#endif
+#ifdef CHACHA_NONCE0_CTR128
+#define CHACHA_UNUSED __unused
+#else
+#define CHACHA_UNUSED
+#endif
+
LOCAL void chacha_keysetup(struct chacha_ctx *x, const u_char *k, u_int kbits);
-LOCAL void chacha_ivsetup(struct chacha_ctx *x, const u_char *iv, const u_char *ctr);
+LOCAL void chacha_ivsetup(struct chacha_ctx *x, const u_char *iv CHACHA_UNUSED,
+ const u_char *ctr);
LOCAL void chacha_encrypt_bytes(struct chacha_ctx *x, const u_char *m,
u_char *c, u_int bytes);
+
+#undef CHACHA_UNUSED
#endif /* CHACHA_H */
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