more btc stuff

1 files changed, 4 insertions, 1 deletions

diff --git a/sys/src/libsec/port/ecc.c b/sys/src/libsec/port/ecc.c
index 27e647d46..2504c7c5c 100644
--- a/sys/src/libsec/port/ecc.c
+++ b/sys/src/libsec/port/ecc.c
@@ -514,6 +514,7 @@ base58dec(char *src, uchar *dst, int len)
 {
 	mpint *n, *b, *r;
 	char *t;
+	int l;
 	
 	n = mpnew(0);
 	r = mpnew(0);
@@ -531,7 +532,9 @@ base58dec(char *src, uchar *dst, int len)
 		mpmul(n, b, n);
 		mpadd(n, r, n);
 	}
-	mptobe(n, dst, len, nil);
+	memset(dst, 0, len);
+	l = (mpsignif(n) + 7) / 8;
+	mptobe(n, dst + (len - l), l, nil);
 	mpfree(n);
 	mpfree(r);
 	mpfree(b);