add ethereum_address_checksum

address.c

@@ -52,3 +52,19 @@ bool address_check_prefix(const uint8_t *addr, uint32_t address_type)
 	}
 	return address_type == ((uint32_t)(addr[0] << 24) | (uint32_t)(addr[1] << 16) | (uint32_t)(addr[2] << 8) | (uint32_t)(addr[3]));
 }
+
+#if USE_ETHEREUM
+#include "sha3.h"
+
+void ethereum_address_checksum(const uint8_t *addr, char *address)
+{
+	const char *hexU = "0123456789ABCDEF", *hexL = "0123456789abcdef";
+	uint8_t hash[32];
+	keccak_256(addr, 20, hash);
+	for (int i = 0; i < 40; i++) {
+		const char *t = (hash[i / 8] & (1 << (7 - i % 8))) ? hexU : hexL;
+		address[i] = (i % 2 == 0) ? t[(addr[i / 2] >> 4) & 0xF] : t[addr[i / 2] & 0xF];
+	}
+	address[40] = 0;
+}
+#endif

address.h

@@ -31,5 +31,8 @@
 size_t address_prefix_bytes_len(uint32_t address_type);
 void address_write_prefix_bytes(uint32_t address_type, uint8_t *out);
 bool address_check_prefix(const uint8_t *addr, uint32_t address_type);
+#if USE_ETHEREUM
+void ethereum_address_checksum(const uint8_t *addr, char *address);
+#endif
 
 #endif

test_check.c

@@ -55,6 +55,7 @@
 #include "ed25519-keccak.h"
 #include "script.h"
 #include "rfc6979.h"
+#include "address.h"
 
 /*
  * This is a clever trick to make Valgrind's Memcheck verify code
@@ -3077,6 +3078,25 @@ START_TEST(test_ethereum_pubkeyhash)
 }
 END_TEST
 
+START_TEST(test_ethereum_address)
+{
+	uint8_t addr[20];
+	char address[41];
+
+	memcpy(addr, fromhex("cd2a3d9f938e13cd947ec05abc7fe734df8dd826"), 20);
+	ethereum_address_checksum(addr, address);
+	ck_assert_str_eq(address, "Cd2a3d9f938e13Cd947eC05ABC7fe734df8DD826");
+
+	memcpy(addr, fromhex("9ca0e998df92c5351cecbbb6dba82ac2266f7e0c"), 20);
+	ethereum_address_checksum(addr, address);
+	ck_assert_str_eq(address, "9Ca0e998dF92c5351cEcbBb6Dba82Ac2266f7e0C");
+
+	memcpy(addr, fromhex("cb16d0e54450cdd2368476e762b09d147972b637"), 20);
+	ethereum_address_checksum(addr, address);
+	ck_assert_str_eq(address, "cB16D0E54450Cdd2368476E762B09D147972b637");
+}
+END_TEST
+
 START_TEST(test_multibyte_address)
 {
 	uint8_t priv_key[32];
@@ -3225,6 +3245,10 @@ Suite *test_suite(void)
 	tcase_add_test(tc, test_address_decode);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("ethereum_address");
+	tcase_add_test(tc, test_ethereum_address);
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("wif");
 	tcase_add_test(tc, test_wif);
 	suite_add_tcase(s, tc);