chore: move sha2 functions into the hash module

docs/docs/noir/standard_library/cryptographic_primitives/hashes.mdx

@@ -15,7 +15,7 @@ import BlackBoxInfo from '@site/src/components/Notes/_blackbox.mdx';
 Given an array of bytes, returns the resulting sha256 hash.
 Specify a message_size to hash only the first `message_size` bytes of the input.
 
-#include_code sha256 noir_stdlib/src/hash/mod.nr rust
+#include_code sha256 noir_stdlib/src/hash/sha256.nr rust
 
 example:
 #include_code sha256_var test_programs/execution_success/sha256/src/main.nr rust

noir_stdlib/src/hash/mod.nr

@@ -2,19 +2,17 @@ mod poseidon;
 mod mimc;
 mod poseidon2;
 mod keccak;
+mod sha256;
+mod sha512;
 
 use crate::default::Default;
 use crate::uint128::U128;
-use crate::sha256::{digest, sha256_var};
 use crate::collections::vec::Vec;
 use crate::embedded_curve_ops::{EmbeddedCurvePoint, EmbeddedCurveScalar, multi_scalar_mul, multi_scalar_mul_slice};
 use crate::meta::derive_via;
 
-#[foreign(sha256)]
-// docs:start:sha256
-pub fn sha256<let N: u32>(input: [u8; N]) -> [u8; 32]
-// docs:end:sha256
-{}
+// Kept for backwards compatibility
+use sha256::{digest, sha256, sha256_compression, sha256_var};
 
 #[foreign(blake2s)]
 // docs:start:blake2s
@@ -137,9 +135,6 @@ pub fn keccak256<let N: u32>(input: [u8; N], message_size: u32) -> [u8; 32]
 #[foreign(poseidon2_permutation)]
 pub fn poseidon2_permutation<let N: u32>(_input: [Field; N], _state_length: u32) -> [Field; N] {}
 
-#[foreign(sha256_compression)]
-pub fn sha256_compression(_input: [u32; 16], _state: [u32; 8]) -> [u32; 8] {}
-
 // Generic hashing support. 
 // Partially ported and impacted by rust.
 

noir_stdlib/src/hash/sha256.nr

@@ -0,0 +1,106 @@
+// Implementation of SHA-256 mapping a byte array of variable length to
+// 32 bytes.
+
+// Deprecated in favour of `sha256_var`
+#[foreign(sha256)]
+// docs:start:sha256
+pub fn sha256<let N: u32>(input: [u8; N]) -> [u8; 32]
+// docs:end:sha256
+{}
+
+#[foreign(sha256_compression)]
+pub fn sha256_compression(_input: [u32; 16], _state: [u32; 8]) -> [u32; 8] {}
+
+// SHA-256 hash function
+#[no_predicates]
+pub fn digest<let N: u32>(msg: [u8; N]) -> [u8; 32] {
+    sha256_var(msg, N as u64)
+}
+
+// Variable size SHA-256 hash
+pub fn sha256_var<let N: u32>(msg: [u8; N], message_size: u64) -> [u8; 32] {
+    let mut msg_block: [u8; 64] = [0; 64];
+    let mut h: [u32; 8] = [1779033703, 3144134277, 1013904242, 2773480762, 1359893119, 2600822924, 528734635, 1541459225]; // Intermediate hash, starting with the canonical initial value
+    let mut i: u64 = 0; // Message byte pointer
+    for k in 0..N {
+        if k as u64 < message_size {
+            // Populate msg_block
+            msg_block[i] = msg[k];
+            i = i + 1;
+            if i == 64 {
+                // Enough to hash block
+                h = crate::hash::sha256_compression(msg_u8_to_u32(msg_block), h);
+
+                i = 0;
+            }
+        }
+    }
+    // Pad the rest such that we have a [u32; 2] block at the end representing the length
+    // of the message, and a block of 1 0 ... 0 following the message (i.e. [1 << 7, 0, ..., 0]).
+    msg_block[i] = 1 << 7;
+    i = i + 1;
+    // If i >= 57, there aren't enough bits in the current message block to accomplish this, so
+    // the 1 and 0s fill up the current block, which we then compress accordingly.
+    if i >= 57 {
+        // Not enough bits (64) to store length. Fill up with zeros.
+        if i < 64 {
+            for _i in 57..64 {
+                if i <= 63 {
+                    msg_block[i] = 0;
+                    i += 1;
+                }
+            }
+        }
+        h = crate::hash::sha256_compression(msg_u8_to_u32(msg_block), h);
+
+        i = 0;
+    }
+
+    let len = 8 * message_size;
+    let len_bytes = (len as Field).to_le_bytes(8);
+    for _i in 0..64 {
+        // In any case, fill blocks up with zeros until the last 64 (i.e. until i = 56).
+        if i < 56 {
+            msg_block[i] = 0;
+            i = i + 1;
+        } else if i < 64 {
+            for j in 0..8 {
+                msg_block[63 - j] = len_bytes[j];
+            }
+            i += 8;
+        }
+    }
+    hash_final_block(msg_block, h)
+}
+
+// Convert 64-byte array to array of 16 u32s
+fn msg_u8_to_u32(msg: [u8; 64]) -> [u32; 16] {
+    let mut msg32: [u32; 16] = [0; 16];
+
+    for i in 0..16 {
+        let mut msg_field: Field = 0;
+        for j in 0..4 {
+            msg_field = msg_field * 256 + msg[64 - 4*(i + 1) + j] as Field;
+        }
+        msg32[15 - i] = msg_field as u32;
+    }
+
+    msg32
+}
+
+fn hash_final_block(msg_block: [u8; 64], mut state: [u32; 8]) -> [u8; 32] {
+    let mut out_h: [u8; 32] = [0; 32]; // Digest as sequence of bytes
+
+    // Hash final padded block
+    state = crate::hash::sha256_compression(msg_u8_to_u32(msg_block), state);
+
+    // Return final hash as byte array
+    for j in 0..8 {
+        let h_bytes = (state[7 - j] as Field).to_le_bytes(4);
+        for k in 0..4 {
+            out_h[31 - 4*j - k] = h_bytes[k];
+        }
+    }
+
+    out_h
+}

noir_stdlib/src/hash/sha512.nr

@@ -0,0 +1,165 @@
+// Implementation of SHA-512 mapping a byte array of variable length to
+// 64 bytes.
+// Internal functions act on 64-bit unsigned integers for simplicity.
+// Auxiliary mappings; names as in FIPS PUB 180-4
+fn rotr64(a: u64, b: u8) -> u64 // 64-bit right rotation
+{
+    // None of the bits overlap between `(a >> b)` and `(a << (64 - b))`
+    // Addition is then equivalent to OR, with fewer constraints.
+    (a >> b) + (a << (64 - b))
+}
+
+fn sha_ch(x: u64, y: u64, z: u64) -> u64 {
+    (x & y) ^ (!x & z)
+}
+
+fn sha_maj(x: u64, y: u64, z: u64) -> u64 {
+    (x & y) ^ (x & z) ^ (y & z)
+}
+
+fn sha_bigma0(x: u64) -> u64 {
+    rotr64(x, 28) ^ rotr64(x, 34) ^ rotr64(x, 39)
+}
+
+fn sha_bigma1(x: u64) -> u64 {
+    rotr64(x, 14) ^ rotr64(x, 18) ^ rotr64(x, 41)
+}
+
+fn sha_sigma0(x: u64) -> u64 {
+    rotr64(x, 1) ^ rotr64(x, 8) ^ (x >> 7)
+}
+
+fn sha_sigma1(x: u64) -> u64 {
+    rotr64(x, 19) ^ rotr64(x, 61) ^ (x >> 6)
+}
+
+fn sha_w(msg: [u64; 16]) -> [u64; 80] // Expanded message blocks
+{
+    let mut w: [u64;80] = [0; 80];
+
+    for j in 0..16 {
+        w[j] = msg[j];
+    }
+
+    for j in 16..80 {
+        w[j] = crate::wrapping_add(
+            crate::wrapping_add(sha_sigma1(w[j-2]), w[j-7]), 
+            crate::wrapping_add(sha_sigma0(w[j-15]), w[j-16]),
+        );
+    }
+    w
+}
+
+// SHA-512 compression function
+#[no_predicates]
+fn sha_c(msg: [u64; 16], hash: [u64; 8]) -> [u64; 8] {
+    // noir-fmt:ignore
+    let K: [u64; 80] = [4794697086780616226, 8158064640168781261, 13096744586834688815, 16840607885511220156, 4131703408338449720, 6480981068601479193, 10538285296894168987, 12329834152419229976, 15566598209576043074, 1334009975649890238, 2608012711638119052, 6128411473006802146, 8268148722764581231, 9286055187155687089, 11230858885718282805, 13951009754708518548, 16472876342353939154, 17275323862435702243, 1135362057144423861, 2597628984639134821, 3308224258029322869, 5365058923640841347, 6679025012923562964, 8573033837759648693, 10970295158949994411, 12119686244451234320, 12683024718118986047, 13788192230050041572, 14330467153632333762, 15395433587784984357, 489312712824947311, 1452737877330783856, 2861767655752347644, 3322285676063803686, 5560940570517711597, 5996557281743188959, 7280758554555802590, 8532644243296465576, 9350256976987008742, 10552545826968843579, 11727347734174303076, 12113106623233404929, 14000437183269869457, 14369950271660146224, 15101387698204529176, 15463397548674623760, 17586052441742319658, 1182934255886127544, 1847814050463011016, 2177327727835720531, 2830643537854262169, 3796741975233480872, 4115178125766777443, 5681478168544905931, 6601373596472566643, 7507060721942968483, 8399075790359081724, 8693463985226723168, 9568029438360202098, 10144078919501101548, 10430055236837252648, 11840083180663258601, 13761210420658862357, 14299343276471374635, 14566680578165727644, 15097957966210449927, 16922976911328602910, 17689382322260857208, 500013540394364858, 748580250866718886, 1242879168328830382, 1977374033974150939, 2944078676154940804, 3659926193048069267, 4368137639120453308, 4836135668995329356, 5532061633213252278, 6448918945643986474, 6902733635092675308, 7801388544844847127]; // first 64 bits of fractional parts of cube roots of first 80 primes
+    let mut out_h: [u64; 8] = hash;
+    let w = sha_w(msg);
+    for j in 0..80 {
+        let out1 = crate::wrapping_add(out_h[7], sha_bigma1(out_h[4]));
+        let out2 = crate::wrapping_add(out1, sha_ch(out_h[4], out_h[5], out_h[6]));
+        let t1 = crate::wrapping_add(crate::wrapping_add(out2, K[j]), w[j]);
+        let t2 = crate::wrapping_add(sha_bigma0(out_h[0]), sha_maj(out_h[0], out_h[1], out_h[2]));
+        out_h[7] = out_h[6];
+        out_h[6] = out_h[5];
+        out_h[5] = out_h[4];
+        out_h[4] = crate::wrapping_add(out_h[3] , t1);
+        out_h[3] = out_h[2];
+        out_h[2] = out_h[1];
+        out_h[1] = out_h[0];
+        out_h[0] = crate::wrapping_add(t1, t2);
+    }
+
+    out_h
+}
+// Convert 128-byte array to array of 16 u64s
+fn msg_u8_to_u64(msg: [u8; 128]) -> [u64; 16] {
+    let mut msg64: [u64; 16] = [0; 16];
+
+    for i in 0..16 {
+        let mut msg_field: Field = 0;
+        for j in 0..8 {
+            msg_field = msg_field * 256 + msg[128 - 8*(i + 1) + j] as Field;
+        }
+        msg64[15 - i] = msg_field as u64;
+    }
+
+    msg64
+}
+// SHA-512 hash function
+pub fn digest<let N: u32>(msg: [u8; N]) -> [u8; 64] {
+    let mut msg_block: [u8; 128] = [0; 128];
+    // noir-fmt:ignore
+    let mut h: [u64; 8] = [7640891576956012808, 13503953896175478587, 4354685564936845355, 11912009170470909681, 5840696475078001361, 11170449401992604703, 2270897969802886507, 6620516959819538809]; // Intermediate hash, starting with the canonical initial value
+    let mut c: [u64; 8] = [0; 8]; // Compression of current message block as sequence of u64
+    let mut out_h: [u8; 64] = [0; 64]; // Digest as sequence of bytes
+    let mut i: u64 = 0; // Message byte pointer
+    for k in 0..msg.len() {
+        // Populate msg_block
+        msg_block[i] = msg[k];
+        i = i + 1;
+        if i == 128 {
+            // Enough to hash block
+            c = sha_c(msg_u8_to_u64(msg_block), h);
+            for j in 0..8 {
+                h[j] = crate::wrapping_add(h[j], c[j]);
+            }
+
+            i = 0;
+        }
+    }
+    // Pad the rest such that we have a [u64; 2] block at the end representing the length
+    // of the message, and a block of 1 0 ... 0 following the message (i.e. [1 << 7, 0, ..., 0]).
+    msg_block[i] = 1 << 7;
+    i += 1;
+    // If i >= 113, there aren't enough bits in the current message block to accomplish this, so
+    // the 1 and 0s fill up the current block, which we then compress accordingly.
+    if i >= 113 {
+        // Not enough bits (128) to store length. Fill up with zeros.
+        if i < 128 {
+            for _i in 113..128 {
+                if i <= 127 {
+                    msg_block[i] = 0;
+                    i += 1;
+                }
+            }
+        }
+        c = sha_c(msg_u8_to_u64(msg_block), h);
+        for j in 0..8 {
+            h[j] = crate::wrapping_add(h[j], c[j]);
+        }
+
+        i = 0;
+    }
+
+    let len = 8 * msg.len();
+    let len_bytes = (len as Field).to_le_bytes(16);
+    for _i in 0..128 {
+        // In any case, fill blocks up with zeros until the last 128 (i.e. until i = 112).
+        if i < 112 {
+            msg_block[i] = 0;
+            i += 1;
+        } else if i < 128 {
+            for j in 0..16 {
+                msg_block[127 - j] = len_bytes[j];
+            }
+            i += 16; // Done.
+        }
+    }
+    // Hash final padded block
+    c = sha_c(msg_u8_to_u64(msg_block), h);
+    for j in 0..8 {
+        h[j] = crate::wrapping_add(h[j], c[j]);
+    }
+    // Return final hash as byte array
+    for j in 0..8 {
+        let h_bytes = (h[7 - j] as Field).to_le_bytes(8);
+        for k in 0..8 {
+            out_h[63 - 8*j - k] = h_bytes[k];
+        }
+    }
+
+    out_h
+}