1 files changed, 29 insertions, 0 deletions
diff --git a/kernel/crypto/ChaCha20/chacha20.c b/kernel/crypto/ChaCha20/chacha20.c
new file mode 100644
index 0000000..5bf7aa2
--- /dev/null
+++ b/kernel/crypto/ChaCha20/chacha20.c
@@ -0,0 +1,29 @@
+#include "chacha20.h"
+
+#define ROTL(a, b) (((a) << (b)) | ((a) >> (32 - (b))))
+#define QR(a, b, c, d)                                                         \
+	(a += b, d ^= a, d = ROTL(d, 16), c += d, b ^= c, b = ROTL(b, 12),     \
+	 a += b, d ^= a, d = ROTL(d, 8), c += d, b ^= c, b = ROTL(b, 7))
+#define ROUNDS 20
+
+void chacha_block(uint32_t out[16], uint32_t const in[16])
+{
+	int i;
+	uint32_t x[16];
+
+	for (i = 0; i < 16; ++i)
+		x[i] = in[i];
+	for (i = 0; i < ROUNDS; i += 2) {
+		QR(x[0], x[4], x[8], x[12]);
+		QR(x[1], x[5], x[9], x[13]);
+		QR(x[2], x[6], x[10], x[14]);
+		QR(x[3], x[7], x[11], x[15]);
+
+		QR(x[0], x[5], x[10], x[15]);
+		QR(x[1], x[6], x[11], x[12]);
+		QR(x[2], x[7], x[8], x[13]);
+		QR(x[3], x[4], x[9], x[14]);
+	}
+	for (i = 0; i < 16; ++i)
+		out[i] = x[i] + in[i];
+}