crypto/pbkdf2: use snake_case for variables like everywhere else

1 files changed, 66 insertions, 69 deletions

diff --git a/lib/std/crypto/pbkdf2.zig b/lib/std/crypto/pbkdf2.zig
index ae09f139a4..52f9da5cd7 100644
--- a/lib/std/crypto/pbkdf2.zig
+++ b/lib/std/crypto/pbkdf2.zig
@@ -20,20 +20,20 @@ const Error = std.crypto.Error;
 // pseudorandom function. See Appendix B.1 for further discussion.)
 // PBKDF2 is recommended for new applications.
 //
-// PBKDF2 (P, S, c, dkLen)
+// PBKDF2 (P, S, c, dk_len)
 //
-// Options:        PRF        underlying pseudorandom function (hLen
+// Options:        PRF        underlying pseudorandom function (h_len
 //                            denotes the length in octets of the
 //                            pseudorandom function output)
 //
 // Input:          P          password, an octet string
 //                 S          salt, an octet string
 //                 c          iteration count, a positive integer
-//                 dkLen      intended length in octets of the derived
+//                 dk_len      intended length in octets of the derived
 //                            key, a positive integer, at most
-//                            (2^32 - 1) * hLen
+//                            (2^32 - 1) * h_len
 //
-// Output:         DK         derived key, a dkLen-octet string
+// Output:         DK         derived key, a dk_len-octet string
 
 // Based on Apple's CommonKeyDerivation, based originally on code by Damien Bergamini.
 
@@ -41,7 +41,7 @@ const Error = std.crypto.Error;
 ///
 /// PBKDF2 is defined in RFC 2898, and is a recommendation of NIST SP 800-132.
 ///
-/// derivedKey: Slice of appropriate size for generated key. Generally 16 or 32 bytes in length.
+/// dk: Slice of appropriate size for generated key. Generally 16 or 32 bytes in length.
 ///             May be uninitialized. All bytes will be overwritten.
 ///             Maximum size is `maxInt(u32) * Hash.digest_length`
 ///             It is a programming error to pass buffer longer than the maximum size.
@@ -52,43 +52,38 @@ const Error = std.crypto.Error;
 ///
 /// rounds: Iteration count. Must be greater than 0. Common values range from 1,000 to 100,000.
 ///         Larger iteration counts improve security by increasing the time required to compute
-///         the derivedKey. It is common to tune this parameter to achieve approximately 100ms.
+///         the dk. It is common to tune this parameter to achieve approximately 100ms.
 ///
 /// Prf: Pseudo-random function to use. A common choice is `std.crypto.auth.hmac.HmacSha256`.
-pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds: u32, comptime Prf: type) Error!void {
+pub fn pbkdf2(dk: []u8, password: []const u8, salt: []const u8, rounds: u32, comptime Prf: type) Error!void {
     if (rounds < 1) return error.WeakParameters;
 
-    const dkLen = derivedKey.len;
-    const hLen = Prf.mac_length;
-    comptime std.debug.assert(hLen >= 1);
+    const dk_len = dk.len;
+    const h_len = Prf.mac_length;
+    comptime std.debug.assert(h_len >= 1);
 
     // FromSpec:
     //
-    //   1. If dkLen > maxInt(u32) * hLen, output "derived key too long" and
+    //   1. If dk_len > maxInt(u32) * h_len, output "derived key too long" and
     //      stop.
     //
-    if (dkLen / hLen >= maxInt(u32)) {
+    if (dk_len / h_len >= maxInt(u32)) {
         // Counter starts at 1 and is 32 bit, so if we have to return more blocks, we would overflow
         return error.OutputTooLong;
     }
 
     // FromSpec:
     //
-    //   2. Let l be the number of hLen-long blocks of bytes in the derived key,
+    //   2. Let l be the number of h_len-long blocks of bytes in the derived key,
     //      rounding up, and let r be the number of bytes in the last
     //      block
     //
 
-    // l will not overflow, proof:
-    // let `L(dkLen, hLen) = (dkLen + hLen - 1) / hLen`
-    // then `L^-1(l, hLen) = l*hLen - hLen + 1`
-    // 1) L^-1(maxInt(u32), hLen) <= maxInt(u32)*hLen
-    // 2) maxInt(u32)*hLen - hLen + 1 <= maxInt(u32)*hLen // subtract maxInt(u32)*hLen + 1
-    // 3) -hLen <= -1 // multiply by -1
-    // 4) hLen >= 1
-    const r_ = dkLen % hLen;
-    const l = @intCast(u32, (dkLen / hLen) + @as(u1, if (r_ == 0) 0 else 1)); // original: (dkLen + hLen - 1) / hLen
-    const r = if (r_ == 0) hLen else r_;
+    const blocks_count = (dk_len + h_len - 1) / h_len;
+    var r = dk_len % h_len;
+    if (r == 0) {
+        r = h_len;
+    }
 
     // FromSpec:
     //
@@ -118,37 +113,38 @@ pub fn pbkdf2(derivedKey: []u8, password: []const u8, salt: []const u8, rounds:
     //  Here, INT (i) is a four-octet encoding of the integer i, most
     //  significant octet first.
     //
-    //  4. Concatenate the blocks and extract the first dkLen octets to
+    //  4. Concatenate the blocks and extract the first dk_len octets to
     //  produce a derived key DK:
     //
     //            DK = T_1 || T_2 ||  ...  || T_l<0..r-1>
-    var block: u32 = 0; // Spec limits to u32
-    while (block < l) : (block += 1) {
-        var prevBlock: [hLen]u8 = undefined;
-        var newBlock: [hLen]u8 = undefined;
+
+    var block: u32 = 0;
+    while (block < blocks_count) : (block += 1) {
+        var prev_block: [h_len]u8 = undefined;
+        var new_block: [h_len]u8 = undefined;
 
         // U_1 = PRF (P, S || INT (i))
-        const blockIndex = mem.toBytes(mem.nativeToBig(u32, block + 1)); // Block index starts at 0001
+        const block_index = mem.toBytes(mem.nativeToBig(u32, block + 1)); // Block index starts at 0001
         var ctx = Prf.init(password);
         ctx.update(salt);
-        ctx.update(blockIndex[0..]);
-        ctx.final(prevBlock[0..]);
+        ctx.update(block_index[0..]);
+        ctx.final(prev_block[0..]);
 
         // Choose portion of DK to write into (T_n) and initialize
-        const offset = block * hLen;
-        const blockLen = if (block != l - 1) hLen else r;
-        const dkBlock: []u8 = derivedKey[offset..][0..blockLen];
-        mem.copy(u8, dkBlock, prevBlock[0..dkBlock.len]);
+        const offset = block * h_len;
+        const block_len = if (block != blocks_count - 1) h_len else r;
+        const dk_block: []u8 = dk[offset..][0..block_len];
+        mem.copy(u8, dk_block, prev_block[0..dk_block.len]);
 
         var i: u32 = 1;
         while (i < rounds) : (i += 1) {
             // U_c = PRF (P, U_{c-1})
-            Prf.create(&newBlock, prevBlock[0..], password);
-            mem.copy(u8, prevBlock[0..], newBlock[0..]);
+            Prf.create(&new_block, prev_block[0..], password);
+            mem.copy(u8, prev_block[0..], new_block[0..]);
 
             // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
-            for (dkBlock) |_, j| {
-                dkBlock[j] ^= newBlock[j];
+            for (dk_block) |_, j| {
+                dk_block[j] ^= new_block[j];
             }
         }
     }
@@ -158,49 +154,50 @@ const htest = @import("test.zig");
 const HmacSha1 = std.crypto.auth.hmac.HmacSha1;
 
 // RFC 6070 PBKDF2 HMAC-SHA1 Test Vectors
+
 test "RFC 6070 one iteration" {
     const p = "password";
     const s = "salt";
     const c = 1;
-    const dkLen = 20;
+    const dk_len = 20;
 
-    var derivedKey: [dkLen]u8 = undefined;
+    var dk: [dk_len]u8 = undefined;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "0c60c80f961f0e71f3a9b524af6012062fe037a6";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
 test "RFC 6070 two iterations" {
     const p = "password";
     const s = "salt";
     const c = 2;
-    const dkLen = 20;
+    const dk_len = 20;
 
-    var derivedKey: [dkLen]u8 = undefined;
+    var dk: [dk_len]u8 = undefined;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "ea6c014dc72d6f8ccd1ed92ace1d41f0d8de8957";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
 test "RFC 6070 4096 iterations" {
     const p = "password";
     const s = "salt";
     const c = 4096;
-    const dkLen = 20;
+    const dk_len = 20;
 
-    var derivedKey: [dkLen]u8 = undefined;
+    var dk: [dk_len]u8 = undefined;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "4b007901b765489abead49d926f721d065a429c1";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
 test "RFC 6070 16,777,216 iterations" {
@@ -212,48 +209,48 @@ test "RFC 6070 16,777,216 iterations" {
     const p = "password";
     const s = "salt";
     const c = 16777216;
-    const dkLen = 20;
+    const dk_len = 20;
 
-    var derivedKey = [_]u8{0} ** dkLen;
+    var dk = [_]u8{0} ** dk_len;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "eefe3d61cd4da4e4e9945b3d6ba2158c2634e984";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
 test "RFC 6070 multi-block salt and password" {
     const p = "passwordPASSWORDpassword";
     const s = "saltSALTsaltSALTsaltSALTsaltSALTsalt";
     const c = 4096;
-    const dkLen = 25;
+    const dk_len = 25;
 
-    var derivedKey: [dkLen]u8 = undefined;
+    var dk: [dk_len]u8 = undefined;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "3d2eec4fe41c849b80c8d83662c0e44a8b291a964cf2f07038";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
 test "RFC 6070 embedded NUL" {
     const p = "pass\x00word";
     const s = "sa\x00lt";
     const c = 4096;
-    const dkLen = 16;
+    const dk_len = 16;
 
-    var derivedKey: [dkLen]u8 = undefined;
+    var dk: [dk_len]u8 = undefined;
 
-    try pbkdf2(&derivedKey, p, s, c, HmacSha1);
+    try pbkdf2(&dk, p, s, c, HmacSha1);
 
     const expected = "56fa6aa75548099dcc37d7f03425e0c3";
 
-    htest.assertEqual(expected, derivedKey[0..]);
+    htest.assertEqual(expected, dk[0..]);
 }
 
-test "Very large dkLen" {
+test "Very large dk_len" {
     // This test allocates 8GB of memory and is expected to take several hours to run.
     if (true) {
         return error.SkipZigTest;
@@ -261,13 +258,13 @@ test "Very large dkLen" {
     const p = "password";
     const s = "salt";
     const c = 1;
-    const dkLen = 1 << 33;
+    const dk_len = 1 << 33;
 
-    var derivedKey = try std.testing.allocator.alloc(u8, dkLen);
+    var dk = try std.testing.allocator.alloc(u8, dk_len);
     defer {
-        std.testing.allocator.free(derivedKey);
+        std.testing.allocator.free(dk);
     }
 
-    try pbkdf2(derivedKey, p, s, c, HmacSha1);
     // Just verify this doesn't crash with an overflow
+    try pbkdf2(dk, p, s, c, HmacSha1);
 }