Move RFC 4880 encoding to rfc4880.h

This allows making pgp_s2k.h internal in the future while leaving the
RFC 4880 logic available.

5 files changed, 115 insertions, 83 deletions

diff --git a/src/lib/pbkdf/pgp_s2k/info.txt b/src/lib/pbkdf/pgp_s2k/info.txt
index 4868dd070..a1c048eaf 100644
--- a/src/lib/pbkdf/pgp_s2k/info.txt
+++ b/src/lib/pbkdf/pgp_s2k/info.txt
@@ -1,5 +1,6 @@
 <defines>
 PGP_S2K -> 20170527
+RFC4880 -> 20210407
 </defines>
 
 <requires>
@@ -8,4 +9,5 @@ hash
 
 <header:public>
 pgp_s2k.h
+rfc4880.h
 </header:public>
diff --git a/src/lib/pbkdf/pgp_s2k/pgp_s2k.cpp b/src/lib/pbkdf/pgp_s2k/pgp_s2k.cpp
index 11409417a..0d78f4358 100644
--- a/src/lib/pbkdf/pgp_s2k/pgp_s2k.cpp
+++ b/src/lib/pbkdf/pgp_s2k/pgp_s2k.cpp
@@ -13,64 +13,6 @@
 
 namespace Botan {
 
-/*
-PGP stores the iteration count as a single byte
-Thus it can only actually take on one of 256 values, based on the
-formula in RFC 4880 section 3.6.1.3
-*/
-static const uint32_t OPENPGP_S2K_ITERS[256] = {
-   1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, 1600,
-   1664, 1728, 1792, 1856, 1920, 1984, 2048, 2176, 2304, 2432,
-   2560, 2688, 2816, 2944, 3072, 3200, 3328, 3456, 3584, 3712,
-   3840, 3968, 4096, 4352, 4608, 4864, 5120, 5376, 5632, 5888,
-   6144, 6400, 6656, 6912, 7168, 7424, 7680, 7936, 8192, 8704,
-   9216, 9728, 10240, 10752, 11264, 11776, 12288, 12800, 13312,
-   13824, 14336, 14848, 15360, 15872, 16384, 17408, 18432, 19456,
-   20480, 21504, 22528, 23552, 24576, 25600, 26624, 27648, 28672,
-   29696, 30720, 31744, 32768, 34816, 36864, 38912, 40960, 43008,
-   45056, 47104, 49152, 51200, 53248, 55296, 57344, 59392, 61440,
-   63488, 65536, 69632, 73728, 77824, 81920, 86016, 90112, 94208,
-   98304, 102400, 106496, 110592, 114688, 118784, 122880, 126976,
-   131072, 139264, 147456, 155648, 163840, 172032, 180224, 188416,
-   196608, 204800, 212992, 221184, 229376, 237568, 245760, 253952,
-   262144, 278528, 294912, 311296, 327680, 344064, 360448, 376832,
-   393216, 409600, 425984, 442368, 458752, 475136, 491520, 507904,
-   524288, 557056, 589824, 622592, 655360, 688128, 720896, 753664,
-   786432, 819200, 851968, 884736, 917504, 950272, 983040, 1015808,
-   1048576, 1114112, 1179648, 1245184, 1310720, 1376256, 1441792,
-   1507328, 1572864, 1638400, 1703936, 1769472, 1835008, 1900544,
-   1966080, 2031616, 2097152, 2228224, 2359296, 2490368, 2621440,
-   2752512, 2883584, 3014656, 3145728, 3276800, 3407872, 3538944,
-   3670016, 3801088, 3932160, 4063232, 4194304, 4456448, 4718592,
-   4980736, 5242880, 5505024, 5767168, 6029312, 6291456, 6553600,
-   6815744, 7077888, 7340032, 7602176, 7864320, 8126464, 8388608,
-   8912896, 9437184, 9961472, 10485760, 11010048, 11534336,
-   12058624, 12582912, 13107200, 13631488, 14155776, 14680064,
-   15204352, 15728640, 16252928, 16777216, 17825792, 18874368,
-   19922944, 20971520, 22020096, 23068672, 24117248, 25165824,
-   26214400, 27262976, 28311552, 29360128, 30408704, 31457280,
-   32505856, 33554432, 35651584, 37748736, 39845888, 41943040,
-   44040192, 46137344, 48234496, 50331648, 52428800, 54525952,
-   56623104, 58720256, 60817408, 62914560, 65011712 };
-
-uint8_t RFC4880_encode_count(size_t desired_iterations)
-   {
-   if(desired_iterations <= OPENPGP_S2K_ITERS[0])
-      return 0;
-
-   if(desired_iterations >= OPENPGP_S2K_ITERS[255])
-      return 255;
-
-   auto i = std::lower_bound(OPENPGP_S2K_ITERS, OPENPGP_S2K_ITERS + 256, desired_iterations);
-
-   return static_cast<uint8_t>(i - OPENPGP_S2K_ITERS);
-   }
-
-size_t RFC4880_decode_count(uint8_t iter)
-   {
-   return OPENPGP_S2K_ITERS[iter];
-   }
-
 namespace {
 
 void pgp_s2k(HashFunction& hash,
diff --git a/src/lib/pbkdf/pgp_s2k/pgp_s2k.h b/src/lib/pbkdf/pgp_s2k/pgp_s2k.h
index 8d148e725..c56142a1d 100644
--- a/src/lib/pbkdf/pgp_s2k/pgp_s2k.h
+++ b/src/lib/pbkdf/pgp_s2k/pgp_s2k.h
@@ -12,37 +12,13 @@
 #include <botan/pbkdf.h>
 #include <botan/pwdhash.h>
 #include <botan/hash.h>
-
-/*
-This header will not be fully internal - the RFC4880 count
-encoding functions will remain here. But the definition of
-OpenPGP_S2K will be made internal
-*/
+#include <botan/rfc4880.h>
 
 //BOTAN_FUTURE_INTERNAL_HEADER(pgp_s2k.h)
 
 namespace Botan {
 
 /**
-* RFC 4880 encodes the iteration count to a single-byte value
-*/
-uint8_t BOTAN_PUBLIC_API(2,8) RFC4880_encode_count(size_t iterations);
-
-/**
-* Decode the iteration count from RFC 4880 encoding
-*/
-size_t BOTAN_PUBLIC_API(2,8) RFC4880_decode_count(uint8_t encoded_iter);
-
-/**
-* Round an arbitrary iteration count to next largest iteration count
-* supported by RFC4880 encoding.
-*/
-inline size_t RFC4880_round_iterations(size_t iterations)
-   {
-   return RFC4880_decode_count(RFC4880_encode_count(iterations));
-   }
-
-/**
 * OpenPGP's S2K
 *
 * See RFC 4880 sections 3.7.1.1, 3.7.1.2, and 3.7.1.3
diff --git a/src/lib/pbkdf/pgp_s2k/rfc4880.cpp b/src/lib/pbkdf/pgp_s2k/rfc4880.cpp
new file mode 100644
index 000000000..5256eff17
--- /dev/null
+++ b/src/lib/pbkdf/pgp_s2k/rfc4880.cpp
@@ -0,0 +1,73 @@
+/*
+* (C) 2021 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/rfc4880.h>
+
+namespace Botan {
+
+namespace {
+
+/*
+PGP stores the iteration count as a single byte
+Thus it can only actually take on one of 256 values, based on the
+formula in RFC 4880 section 3.6.1.3
+*/
+static const uint32_t OPENPGP_S2K_ITERS[256] = {
+   1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, 1600,
+   1664, 1728, 1792, 1856, 1920, 1984, 2048, 2176, 2304, 2432,
+   2560, 2688, 2816, 2944, 3072, 3200, 3328, 3456, 3584, 3712,
+   3840, 3968, 4096, 4352, 4608, 4864, 5120, 5376, 5632, 5888,
+   6144, 6400, 6656, 6912, 7168, 7424, 7680, 7936, 8192, 8704,
+   9216, 9728, 10240, 10752, 11264, 11776, 12288, 12800, 13312,
+   13824, 14336, 14848, 15360, 15872, 16384, 17408, 18432, 19456,
+   20480, 21504, 22528, 23552, 24576, 25600, 26624, 27648, 28672,
+   29696, 30720, 31744, 32768, 34816, 36864, 38912, 40960, 43008,
+   45056, 47104, 49152, 51200, 53248, 55296, 57344, 59392, 61440,
+   63488, 65536, 69632, 73728, 77824, 81920, 86016, 90112, 94208,
+   98304, 102400, 106496, 110592, 114688, 118784, 122880, 126976,
+   131072, 139264, 147456, 155648, 163840, 172032, 180224, 188416,
+   196608, 204800, 212992, 221184, 229376, 237568, 245760, 253952,
+   262144, 278528, 294912, 311296, 327680, 344064, 360448, 376832,
+   393216, 409600, 425984, 442368, 458752, 475136, 491520, 507904,
+   524288, 557056, 589824, 622592, 655360, 688128, 720896, 753664,
+   786432, 819200, 851968, 884736, 917504, 950272, 983040, 1015808,
+   1048576, 1114112, 1179648, 1245184, 1310720, 1376256, 1441792,
+   1507328, 1572864, 1638400, 1703936, 1769472, 1835008, 1900544,
+   1966080, 2031616, 2097152, 2228224, 2359296, 2490368, 2621440,
+   2752512, 2883584, 3014656, 3145728, 3276800, 3407872, 3538944,
+   3670016, 3801088, 3932160, 4063232, 4194304, 4456448, 4718592,
+   4980736, 5242880, 5505024, 5767168, 6029312, 6291456, 6553600,
+   6815744, 7077888, 7340032, 7602176, 7864320, 8126464, 8388608,
+   8912896, 9437184, 9961472, 10485760, 11010048, 11534336,
+   12058624, 12582912, 13107200, 13631488, 14155776, 14680064,
+   15204352, 15728640, 16252928, 16777216, 17825792, 18874368,
+   19922944, 20971520, 22020096, 23068672, 24117248, 25165824,
+   26214400, 27262976, 28311552, 29360128, 30408704, 31457280,
+   32505856, 33554432, 35651584, 37748736, 39845888, 41943040,
+   44040192, 46137344, 48234496, 50331648, 52428800, 54525952,
+   56623104, 58720256, 60817408, 62914560, 65011712 };
+
+}
+
+uint8_t RFC4880_encode_count(size_t desired_iterations)
+   {
+   if(desired_iterations <= OPENPGP_S2K_ITERS[0])
+      return 0;
+
+   if(desired_iterations >= OPENPGP_S2K_ITERS[255])
+      return 255;
+
+   auto i = std::lower_bound(OPENPGP_S2K_ITERS, OPENPGP_S2K_ITERS + 256, desired_iterations);
+
+   return static_cast<uint8_t>(i - OPENPGP_S2K_ITERS);
+   }
+
+size_t RFC4880_decode_count(uint8_t iter)
+   {
+   return OPENPGP_S2K_ITERS[iter];
+   }
+
+}
diff --git a/src/lib/pbkdf/pgp_s2k/rfc4880.h b/src/lib/pbkdf/pgp_s2k/rfc4880.h
new file mode 100644
index 000000000..8d751985c
--- /dev/null
+++ b/src/lib/pbkdf/pgp_s2k/rfc4880.h
@@ -0,0 +1,39 @@
+/*
+* (C) 2021 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_RFC4880_H_
+#define BOTAN_RFC4880_H_
+
+#include <botan/types.h>
+
+namespace Botan {
+
+/*
+Helpers for encoding PGP S2K values (see RFC 4880)
+*/
+
+/**
+* RFC 4880 encodes the iteration count to a single-byte value
+*/
+uint8_t BOTAN_PUBLIC_API(2,8) RFC4880_encode_count(size_t iterations);
+
+/**
+* Decode the iteration count from RFC 4880 encoding
+*/
+size_t BOTAN_PUBLIC_API(2,8) RFC4880_decode_count(uint8_t encoded_iter);
+
+/**
+* Round an arbitrary iteration count to next largest iteration count
+* supported by RFC4880 encoding.
+*/
+inline size_t RFC4880_round_iterations(size_t iterations)
+   {
+   return RFC4880_decode_count(RFC4880_encode_count(iterations));
+   }
+
+}
+
+#endif