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-rw-r--r--src/Makefile.am2
-rw-r--r--src/Makefile.test.include1
-rw-r--r--src/bech32.cpp191
-rw-r--r--src/bech32.h25
-rw-r--r--src/test/bech32_tests.cpp67
5 files changed, 286 insertions, 0 deletions
diff --git a/src/Makefile.am b/src/Makefile.am
index ebae53a8c1..c71e457ebe 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -78,6 +78,7 @@ BITCOIN_CORE_H = \
addrdb.h \
addrman.h \
base58.h \
+ bech32.h \
bloom.h \
blockencodings.h \
chain.h \
@@ -316,6 +317,7 @@ libbitcoin_common_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
libbitcoin_common_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
libbitcoin_common_a_SOURCES = \
base58.cpp \
+ bech32.cpp \
chainparams.cpp \
coins.cpp \
compressor.cpp \
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index 3a932f460d..ed95f345b1 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -31,6 +31,7 @@ BITCOIN_TESTS =\
test/base32_tests.cpp \
test/base58_tests.cpp \
test/base64_tests.cpp \
+ test/bech32_tests.cpp \
test/bip32_tests.cpp \
test/blockencodings_tests.cpp \
test/bloom_tests.cpp \
diff --git a/src/bech32.cpp b/src/bech32.cpp
new file mode 100644
index 0000000000..573eac58bb
--- /dev/null
+++ b/src/bech32.cpp
@@ -0,0 +1,191 @@
+// Copyright (c) 2017 Pieter Wuille
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "bech32.h"
+
+namespace
+{
+
+typedef std::vector<uint8_t> data;
+
+/** The Bech32 character set for encoding. */
+const char* CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l";
+
+/** The Bech32 character set for decoding. */
+const int8_t CHARSET_REV[128] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ 15, -1, 10, 17, 21, 20, 26, 30, 7, 5, -1, -1, -1, -1, -1, -1,
+ -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
+ 1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1,
+ -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1,
+ 1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1
+};
+
+/** Concatenate two byte arrays. */
+data Cat(data x, const data& y)
+{
+ x.insert(x.end(), y.begin(), y.end());
+ return x;
+}
+
+/** This function will compute what 6 5-bit values to XOR into the last 6 input values, in order to
+ * make the checksum 0. These 6 values are packed together in a single 30-bit integer. The higher
+ * bits correspond to earlier values. */
+uint32_t PolyMod(const data& v)
+{
+ // The input is interpreted as a list of coefficients of a polynomial over F = GF(32), with an
+ // implicit 1 in front. If the input is [v0,v1,v2,v3,v4], that polynomial is v(x) =
+ // 1*x^5 + v0*x^4 + v1*x^3 + v2*x^2 + v3*x + v4. The implicit 1 guarantees that
+ // [v0,v1,v2,...] has a distinct checksum from [0,v0,v1,v2,...].
+
+ // The output is a 30-bit integer whose 5-bit groups are the coefficients of the remainder of
+ // v(x) mod g(x), where g(x) is the Bech32 generator,
+ // x^6 + {29}x^5 + {22}x^4 + {20}x^3 + {21}x^2 + {29}x + {18}. g(x) is chosen in such a way
+ // that the resulting code is a BCH code, guaranteeing detection of up to 3 errors within a
+ // window of 1023 characters. Among the various possible BCH codes, one was selected to in
+ // fact guarantee detection of up to 4 errors within a window of 89 characters.
+
+ // Note that the coefficients are elements of GF(32), here represented as decimal numbers
+ // between {}. In this finite field, addition is just XOR of the corresponding numbers. For
+ // example, {27} + {13} = {27 ^ 13} = {22}. Multiplication is more complicated, and requires
+ // treating the bits of values themselves as coefficients of a polynomial over a smaller field,
+ // GF(2), and multiplying those polynomials mod a^5 + a^3 + 1. For example, {5} * {26} =
+ // (a^2 + 1) * (a^4 + a^3 + a) = (a^4 + a^3 + a) * a^2 + (a^4 + a^3 + a) = a^6 + a^5 + a^4 + a
+ // = a^3 + 1 (mod a^5 + a^3 + 1) = {9}.
+
+ // During the course of the loop below, `c` contains the bitpacked coefficients of the
+ // polynomial constructed from just the values of v that were processed so far, mod g(x). In
+ // the above example, `c` initially corresponds to 1 mod (x), and after processing 2 inputs of
+ // v, it corresponds to x^2 + v0*x + v1 mod g(x). As 1 mod g(x) = 1, that is the starting value
+ // for `c`.
+ uint32_t c = 1;
+ for (auto v_i : v) {
+ // We want to update `c` to correspond to a polynomial with one extra term. If the initial
+ // value of `c` consists of the coefficients of c(x) = f(x) mod g(x), we modify it to
+ // correspond to c'(x) = (f(x) * x + v_i) mod g(x), where v_i is the next input to
+ // process. Simplifying:
+ // c'(x) = (f(x) * x + v_i) mod g(x)
+ // ((f(x) mod g(x)) * x + v_i) mod g(x)
+ // (c(x) * x + v_i) mod g(x)
+ // If c(x) = c0*x^5 + c1*x^4 + c2*x^3 + c3*x^2 + c4*x + c5, we want to compute
+ // c'(x) = (c0*x^5 + c1*x^4 + c2*x^3 + c3*x^2 + c4*x + c5) * x + v_i mod g(x)
+ // = c0*x^6 + c1*x^5 + c2*x^4 + c3*x^3 + c4*x^2 + c5*x + v_i mod g(x)
+ // = c0*(x^6 mod g(x)) + c1*x^5 + c2*x^4 + c3*x^3 + c4*x^2 + c5*x + v_i
+ // If we call (x^6 mod g(x)) = k(x), this can be written as
+ // c'(x) = (c1*x^5 + c2*x^4 + c3*x^3 + c4*x^2 + c5*x + v_i) + c0*k(x)
+
+ // First, determine the value of c0:
+ uint8_t c0 = c >> 25;
+
+ // Then compute c1*x^5 + c2*x^4 + c3*x^3 + c4*x^2 + c5*x + v_i:
+ c = ((c & 0x1ffffff) << 5) ^ v_i;
+
+ // Finally, for each set bit n in c0, conditionally add {2^n}k(x):
+ if (c0 & 1) c ^= 0x3b6a57b2; // k(x) = {29}x^5 + {22}x^4 + {20}x^3 + {21}x^2 + {29}x + {18}
+ if (c0 & 2) c ^= 0x26508e6d; // {2}k(x) = {19}x^5 + {5}x^4 + x^3 + {3}x^2 + {19}x + {13}
+ if (c0 & 4) c ^= 0x1ea119fa; // {4}k(x) = {15}x^5 + {10}x^4 + {2}x^3 + {6}x^2 + {15}x + {26}
+ if (c0 & 8) c ^= 0x3d4233dd; // {8}k(x) = {30}x^5 + {20}x^4 + {4}x^3 + {12}x^2 + {30}x + {29}
+ if (c0 & 16) c ^= 0x2a1462b3; // {16}k(x) = {21}x^5 + x^4 + {8}x^3 + {24}x^2 + {21}x + {19}
+ }
+ return c;
+}
+
+/** Convert to lower case. */
+inline unsigned char LowerCase(unsigned char c)
+{
+ return (c >= 'A' && c <= 'Z') ? (c - 'A') + 'a' : c;
+}
+
+/** Expand a HRP for use in checksum computation. */
+data ExpandHRP(const std::string& hrp)
+{
+ data ret;
+ ret.reserve(hrp.size() + 90);
+ ret.resize(hrp.size() * 2 + 1);
+ for (size_t i = 0; i < hrp.size(); ++i) {
+ unsigned char c = hrp[i];
+ ret[i] = c >> 5;
+ ret[i + hrp.size() + 1] = c & 0x1f;
+ }
+ ret[hrp.size()] = 0;
+ return ret;
+}
+
+/** Verify a checksum. */
+bool VerifyChecksum(const std::string& hrp, const data& values)
+{
+ // PolyMod computes what value to xor into the final values to make the checksum 0. However,
+ // if we required that the checksum was 0, it would be the case that appending a 0 to a valid
+ // list of values would result in a new valid list. For that reason, Bech32 requires the
+ // resulting checksum to be 1 instead.
+ return PolyMod(Cat(ExpandHRP(hrp), values)) == 1;
+}
+
+/** Create a checksum. */
+data CreateChecksum(const std::string& hrp, const data& values)
+{
+ data enc = Cat(ExpandHRP(hrp), values);
+ enc.resize(enc.size() + 6); // Append 6 zeroes
+ uint32_t mod = PolyMod(enc) ^ 1; // Determine what to XOR into those 6 zeroes.
+ data ret(6);
+ for (size_t i = 0; i < 6; ++i) {
+ // Convert the 5-bit groups in mod to checksum values.
+ ret[i] = (mod >> (5 * (5 - i))) & 31;
+ }
+ return ret;
+}
+
+} // namespace
+
+namespace bech32
+{
+
+/** Encode a Bech32 string. */
+std::string Encode(const std::string& hrp, const data& values) {
+ data checksum = CreateChecksum(hrp, values);
+ data combined = Cat(values, checksum);
+ std::string ret = hrp + '1';
+ ret.reserve(ret.size() + combined.size());
+ for (auto c : combined) {
+ ret += CHARSET[c];
+ }
+ return ret;
+}
+
+/** Decode a Bech32 string. */
+std::pair<std::string, data> Decode(const std::string& str) {
+ bool lower = false, upper = false;
+ for (size_t i = 0; i < str.size(); ++i) {
+ unsigned char c = str[i];
+ if (c < 33 || c > 126) return {};
+ if (c >= 'a' && c <= 'z') lower = true;
+ if (c >= 'A' && c <= 'Z') upper = true;
+ }
+ if (lower && upper) return {};
+ size_t pos = str.rfind('1');
+ if (str.size() > 90 || pos == str.npos || pos == 0 || pos + 7 > str.size()) {
+ return {};
+ }
+ data values(str.size() - 1 - pos);
+ for (size_t i = 0; i < str.size() - 1 - pos; ++i) {
+ unsigned char c = str[i + pos + 1];
+ int8_t rev = (c < 33 || c > 126) ? -1 : CHARSET_REV[c];
+ if (rev == -1) {
+ return {};
+ }
+ values[i] = rev;
+ }
+ std::string hrp;
+ for (size_t i = 0; i < pos; ++i) {
+ hrp += LowerCase(str[i]);
+ }
+ if (!VerifyChecksum(hrp, values)) {
+ return {};
+ }
+ return {hrp, data(values.begin(), values.end() - 6)};
+}
+
+} // namespace bech32
diff --git a/src/bech32.h b/src/bech32.h
new file mode 100644
index 0000000000..7ef7b22213
--- /dev/null
+++ b/src/bech32.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2017 Pieter Wuille
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+// Bech32 is a string encoding format used in newer address types.
+// The output consists of a human-readable part (alphanumeric), a
+// separator character (1), and a base32 data section, the last
+// 6 characters of which are a checksum.
+//
+// For more information, see BIP 173.
+
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+namespace bech32
+{
+
+/** Encode a Bech32 string. Returns the empty string in case of failure. */
+std::string Encode(const std::string& hrp, const std::vector<uint8_t>& values);
+
+/** Decode a Bech32 string. Returns (hrp, data). Empty hrp means failure. */
+std::pair<std::string, std::vector<uint8_t>> Decode(const std::string& str);
+
+} // namespace bech32
diff --git a/src/test/bech32_tests.cpp b/src/test/bech32_tests.cpp
new file mode 100644
index 0000000000..ce4cddd64b
--- /dev/null
+++ b/src/test/bech32_tests.cpp
@@ -0,0 +1,67 @@
+// Copyright (c) 2017 Pieter Wuille
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "bech32.h"
+#include "test/test_bitcoin.h"
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(bech32_tests, BasicTestingSetup)
+
+bool CaseInsensitiveEqual(const std::string &s1, const std::string &s2)
+{
+ if (s1.size() != s2.size()) return false;
+ for (size_t i = 0; i < s1.size(); ++i) {
+ char c1 = s1[i];
+ if (c1 >= 'A' && c1 <= 'Z') c1 -= ('A' - 'a');
+ char c2 = s2[i];
+ if (c2 >= 'A' && c2 <= 'Z') c2 -= ('A' - 'a');
+ if (c1 != c2) return false;
+ }
+ return true;
+}
+
+BOOST_AUTO_TEST_CASE(bip173_testvectors_valid)
+{
+ static const std::string CASES[] = {
+ "A12UEL5L",
+ "a12uel5l",
+ "an83characterlonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1tt5tgs",
+ "abcdef1qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw",
+ "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqc8247j",
+ "split1checkupstagehandshakeupstreamerranterredcaperred2y9e3w",
+ "?1ezyfcl",
+ };
+ for (const std::string& str : CASES) {
+ auto ret = bech32::Decode(str);
+ BOOST_CHECK(!ret.first.empty());
+ std::string recode = bech32::Encode(ret.first, ret.second);
+ BOOST_CHECK(!recode.empty());
+ BOOST_CHECK(CaseInsensitiveEqual(str, recode));
+ }
+}
+
+BOOST_AUTO_TEST_CASE(bip173_testvectors_invalid)
+{
+ static const std::string CASES[] = {
+ " 1nwldj5",
+ "\x7f""1axkwrx",
+ "\x80""1eym55h",
+ "an84characterslonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1569pvx",
+ "pzry9x0s0muk",
+ "1pzry9x0s0muk",
+ "x1b4n0q5v",
+ "li1dgmt3",
+ "de1lg7wt\xff",
+ "A1G7SGD8",
+ "10a06t8",
+ "1qzzfhee",
+ };
+ for (const std::string& str : CASES) {
+ auto ret = bech32::Decode(str);
+ BOOST_CHECK(ret.first.empty());
+ }
+}
+
+BOOST_AUTO_TEST_SUITE_END()
generated by cgit v1.2.3 (git 2.26.2) at 2024-11-02 08:26:45 +0000