diff --git a/vlib/crypto/md5/md5.v b/vlib/crypto/md5/md5.v
index 9870a4271f..4d669447d4 100644
--- a/vlib/crypto/md5/md5.v
+++ b/vlib/crypto/md5/md5.v
@@ -48,7 +48,7 @@ fn (d mut Digest) reset() {
 	d.len = u64(0)
 }
 
-// new returns a new hash.Hash computing the MD5 checksum.
+// new returns a new Digest (implementing hash.Hash) computing the MD5 checksum.
 pub fn new() *Digest {
 	mut d := &Digest{}
 	d.reset()
diff --git a/vlib/crypto/md5/md5block_generic.v b/vlib/crypto/md5/md5block_generic.v
index c22e431429..16735f1be0 100644
--- a/vlib/crypto/md5/md5block_generic.v
+++ b/vlib/crypto/md5/md5block_generic.v
@@ -17,6 +17,7 @@ fn block_generic(dig &Digest, p []byte) {
 	mut b := dig.s[1]
 	mut c := dig.s[2]
 	mut d := dig.s[3]
+	
 	for i := 0; i <= p.len-BlockSize; i += BlockSize {
 		mut q := p.right(i)
 		q = q.left(BlockSize)
diff --git a/vlib/crypto/sha1/sha1.v b/vlib/crypto/sha1/sha1.v
index ab1d23a223..b513831c3d 100644
--- a/vlib/crypto/sha1/sha1.v
+++ b/vlib/crypto/sha1/sha1.v
@@ -143,9 +143,9 @@ pub fn sum(data []byte) []byte {
 }
 
 fn block(dig &Digest, p []byte) {
-    // For now just use block_generic until we have specific
+	// For now just use block_generic until we have specific
 	// architecture optimized versions
-    block_generic(dig, p)
+	block_generic(dig, p)
 }
 
 pub fn (d &Digest) size() int { return Size }
diff --git a/vlib/crypto/sha256/sha256.v b/vlib/crypto/sha256/sha256.v
new file mode 100644
index 0000000000..adb0e64614
--- /dev/null
+++ b/vlib/crypto/sha256/sha256.v
@@ -0,0 +1,218 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+// Package sha256 implements the SHA224 and SHA256 hash algorithms as defined
+// in FIPS 180-4.
+
+// Adaped from https://github.com/golang/go/tree/master/src/crypto/sha256
+
+module sha256
+
+import math
+import encoding.binary
+
+const (
+	// The size of a SHA256 checksum in bytes.
+	Size = 32
+	// The size of a SHA224 checksum in bytes.
+	Size224 = 28
+	// The blocksize of SHA256 and SHA224 in bytes.
+	BlockSize = 64
+)
+
+const (
+	Chunk     = 64
+	Init0     = 0x6A09E667
+	Init1     = 0xBB67AE85
+	Init2     = 0x3C6EF372
+	Init3     = 0xA54FF53A
+	Init4     = 0x510E527F
+	Init5     = 0x9B05688C
+	Init6     = 0x1F83D9AB
+	Init7     = 0x5BE0CD19
+	Init0_224 = 0xC1059ED8
+	Init1_224 = 0x367CD507
+	Init2_224 = 0x3070DD17
+	Init3_224 = 0xF70E5939
+	Init4_224 = 0xFFC00B31
+	Init5_224 = 0x68581511
+	Init6_224 = 0x64F98FA7
+	Init7_224 = 0xBEFA4FA4
+)
+
+// digest represents the partial evaluation of a checksum.
+struct Digest {
+mut:
+	h     []u32
+	x     []byte
+	nx    int
+	len   u64
+	is224 bool // mark if this digest is SHA-224
+}
+
+fn (d &Digest) reset() {
+	d.h = [u32(0); 8]
+	d.x = [byte(0); Chunk]
+	if !d.is224 {
+		d.h[0] = u32(Init0)
+		d.h[1] = u32(Init1)
+		d.h[2] = u32(Init2)
+		d.h[3] = u32(Init3)
+		d.h[4] = u32(Init4)
+		d.h[5] = u32(Init5)
+		d.h[6] = u32(Init6)
+		d.h[7] = u32(Init7)
+	} else {
+		d.h[0] = u32(Init0_224)
+		d.h[1] = u32(Init1_224)
+		d.h[2] = u32(Init2_224)
+		d.h[3] = u32(Init3_224)
+		d.h[4] = u32(Init4_224)
+		d.h[5] = u32(Init5_224)
+		d.h[6] = u32(Init6_224)
+		d.h[7] = u32(Init7_224)
+	}
+	d.nx = 0
+	d.len = u64(0)
+}
+
+// new returns a new Digest (implementing hash.Hash) computing the SHA256 checksum.
+pub fn new() *Digest {
+	mut d := &Digest{}
+	d.reset()
+	return d
+}
+
+// new224 returns a new Digest (implementing hash.Hash) computing the SHA224 checksum.
+pub fn new224() *Digest {
+	mut d := &Digest{}
+	d.is224 = true
+	d.reset()
+	return d
+}
+
+fn (d mut Digest) write(p []byte) ?int {
+	nn := p.len
+	d.len += u64(nn)
+	if d.nx > 0 {
+		n := int(math.min(f64(d.x.len), f64(p.len)))
+		for i:=0; i<n; i++ {
+			d.x.set(i+d.nx, p[i])
+		}
+		d.nx += n
+		if d.nx == Chunk {
+			block(d, d.x)
+			d.nx = 0
+		}
+		if n >= p.len {
+			p = []byte
+		} else {
+			p = p.right(n)
+		}
+	}
+	if p.len >= Chunk {
+		n := p.len &~ (Chunk - 1)
+		block(d, p.left(n))
+		if n >= p.len {
+			p = []byte
+		} else {
+			p = p.right(n)
+		}
+	}
+	if p.len > 0 {
+		d.nx = int(math.min(f64(d.x.len), f64(p.len)))
+		for i:=0; i<d.nx; i++ {
+			d.x.set(i, p[i])
+		}
+	}
+	return nn
+}
+
+fn (d &Digest) sum(b_in mut []byte) []byte {
+	// Make a copy of d so that caller can keep writing and summing.
+	mut d0 := *d
+	hash := d0.checksum()
+	if d0.is224 {
+		for b in hash.left(Size224) {
+			b_in << b
+		}
+	} else {
+		for b in hash {
+			b_in << b
+		}
+	}
+	return *b_in
+}
+
+fn (d mut Digest) checksum() []byte {
+	mut len := d.len
+	// Padding. Add a 1 bit and 0 bits until 56 bytes mod 64.
+	mut tmp := [byte(0); 64]
+	tmp[0] = 0x80
+	if int(len)%64 < 56 {
+		d.write(tmp.left(56-int(len)%64))
+	} else {
+		d.write(tmp.left(64+56-int(len)%64))
+	}
+
+	// Length in bits.
+	len <<= u64(3)
+	binary.big_endian_put_u64(tmp, len)
+	d.write(tmp.left(8))
+
+	if d.nx != 0 {
+		panic('d.nx != 0')
+	}
+
+	digest := [byte(0); Size]
+
+	binary.big_endian_put_u32(digest, d.h[0])
+	binary.big_endian_put_u32(digest.right(4), d.h[1])
+	binary.big_endian_put_u32(digest.right(8), d.h[2])
+	binary.big_endian_put_u32(digest.right(12), d.h[3])
+	binary.big_endian_put_u32(digest.right(16), d.h[4])
+	binary.big_endian_put_u32(digest.right(20), d.h[5])
+	binary.big_endian_put_u32(digest.right(24), d.h[6])
+	if !d.is224 {
+		binary.big_endian_put_u32(digest.right(28), d.h[7])
+	}
+
+	return digest
+}
+
+// sum256 returns the SHA256 checksum of the data.
+pub fn sum(data []byte) []byte {
+	return sum256(data)
+}
+
+// sum256 returns the SHA256 checksum of the data.
+pub fn sum256(data []byte) []byte {
+	mut d := new()
+	d.write(data)
+	return d.checksum()
+}
+
+// sum224 returns the SHA224 checksum of the data.
+pub fn sum224(data []byte) []byte {
+	mut d := new224()
+	d.write(data)
+	sum := d.checksum()
+	sum224 := sum.left(Size224)
+	return sum224
+}
+
+fn block(dig &Digest, p []byte) {
+	// For now just use block_generic until we have specific
+	// architecture optimized versions
+	block_generic(dig, p)
+}
+
+pub fn (d &Digest) size() int {
+	if !d.is224 {
+		return Size
+	}
+	return Size224
+}
+
+pub fn (d &Digest) block_size() int { return BlockSize }
diff --git a/vlib/crypto/sha256/sha256_test.v b/vlib/crypto/sha256/sha256_test.v
new file mode 100644
index 0000000000..144158e4f2
--- /dev/null
+++ b/vlib/crypto/sha256/sha256_test.v
@@ -0,0 +1,9 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+import crypto.sha256
+
+fn test_crypto_sha256() {
+	assert sha256.sum('This is a sha256 checksum.'.bytes()).hex() == 'DC7163299659529EAE29683EB1FFEC50D6C8FC7275ECB10C145FDE0E125B8727'
+}
diff --git a/vlib/crypto/sha256/sha256block_generic.v b/vlib/crypto/sha256/sha256block_generic.v
new file mode 100644
index 0000000000..c31923f5cb
--- /dev/null
+++ b/vlib/crypto/sha256/sha256block_generic.v
@@ -0,0 +1,158 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+// SHA256 block step.
+// This is the generic version with no architecture optimizations.
+// In its own file so that an architecture
+// optimized verision can be substituted
+
+module sha256
+
+import math.bits
+
+const (
+	_K = [
+		0x428a2f98,
+		0x71374491,
+		0xb5c0fbcf,
+		0xe9b5dba5,
+		0x3956c25b,
+		0x59f111f1,
+		0x923f82a4,
+		0xab1c5ed5,
+		0xd807aa98,
+		0x12835b01,
+		0x243185be,
+		0x550c7dc3,
+		0x72be5d74,
+		0x80deb1fe,
+		0x9bdc06a7,
+		0xc19bf174,
+		0xe49b69c1,
+		0xefbe4786,
+		0x0fc19dc6,
+		0x240ca1cc,
+		0x2de92c6f,
+		0x4a7484aa,
+		0x5cb0a9dc,
+		0x76f988da,
+		0x983e5152,
+		0xa831c66d,
+		0xb00327c8,
+		0xbf597fc7,
+		0xc6e00bf3,
+		0xd5a79147,
+		0x06ca6351,
+		0x14292967,
+		0x27b70a85,
+		0x2e1b2138,
+		0x4d2c6dfc,
+		0x53380d13,
+		0x650a7354,
+		0x766a0abb,
+		0x81c2c92e,
+		0x92722c85,
+		0xa2bfe8a1,
+		0xa81a664b,
+		0xc24b8b70,
+		0xc76c51a3,
+		0xd192e819,
+		0xd6990624,
+		0xf40e3585,
+		0x106aa070,
+		0x19a4c116,
+		0x1e376c08,
+		0x2748774c,
+		0x34b0bcb5,
+		0x391c0cb3,
+		0x4ed8aa4a,
+		0x5b9cca4f,
+		0x682e6ff3,
+		0x748f82ee,
+		0x78a5636f,
+		0x84c87814,
+		0x8cc70208,
+		0x90befffa,
+		0xa4506ceb,
+		0xbef9a3f7,
+		0xc67178f2,
+	]
+)
+
+fn block_generic(dig &Digest, p []byte) {
+	mut w := [u32(0); 64]
+	
+	mut h0 := dig.h[0]
+	mut h1 := dig.h[1]
+	mut h2 := dig.h[2]
+	mut h3 := dig.h[3]
+	mut h4 := dig.h[4]
+	mut h5 := dig.h[5]
+	mut h6 := dig.h[6]
+	mut h7 := dig.h[7]
+
+	for p.len >= Chunk {
+		// Can interlace the computation of w with the
+		// rounds below if needed for speed.
+		for i := 0; i < 16; i++ {
+			j := i * 4
+			w[i] = u32(u32(p[j])<<u32(24)) | u32(u32(p[j+1])<<u32(16)) | u32(u32(p[j+2])<<u32(8)) | u32(p[j+3])
+		}
+		for i := 16; i < 64; i++ {
+			v1 := w[i-2]
+			t1 := (bits.rotate_left_32(v1, -17)) ^ (bits.rotate_left_32(v1, -19)) ^ u32((v1 >> u32(10)))
+			v2 := w[i-15]
+			t2 := (bits.rotate_left_32(v2, -7)) ^ (bits.rotate_left_32(v2, -18)) ^ u32((v2 >> u32(3)))
+			w[i] = t1 + w[i-7] + t2 + w[i-16]
+		}
+
+		mut a := h0
+		mut b := h1
+		mut c := h2
+		mut d := h3
+		mut e := h4
+		mut f := h5
+		mut g := h6
+		mut h := h7
+
+		for i := 0; i < 64; i++ {
+			t1 := h + ((bits.rotate_left_32(e, -6)) ^ (bits.rotate_left_32(e, -11)) ^ (bits.rotate_left_32(e, -25))) + ((e & f) ^ (~e & g)) + u32(_K[i]) + w[i]
+
+			t2 := ((bits.rotate_left_32(a, -2)) ^ (bits.rotate_left_32(a, -13)) ^ (bits.rotate_left_32(a, -22))) + ((a & b) ^ (a & c) ^ (b & c))
+
+			h = g
+			g = f
+			f = e
+			e = d + t1
+			d = c
+			c = b
+			b = a
+			a = t1 + t2
+		}
+
+		h0 += a
+		h1 += b
+		h2 += c
+		h3 += d
+		h4 += e
+		h5 += f
+		h6 += g
+		h7 += h
+
+		if Chunk >= p.len {
+			p = []byte
+		} else {
+			p = p.right(Chunk)
+		}
+	}
+
+	dig.h[0] = h0
+	dig.h[1] = h1
+	dig.h[2] = h2
+	dig.h[3] = h3
+	dig.h[4] = h4
+	dig.h[5] = h5
+	dig.h[6] = h6
+	dig.h[7] = h7
+}
diff --git a/vlib/crypto/sha512/sha512.v b/vlib/crypto/sha512/sha512.v
index d28a57a458..8a411892f4 100644
--- a/vlib/crypto/sha512/sha512.v
+++ b/vlib/crypto/sha512/sha512.v
@@ -5,7 +5,7 @@
 // Package sha512 implements the SHA-384, SHA-512, SHA-512/224, and SHA-512/256
 // hash algorithms as defined in FIPS 180-4.
 
-// Adaped from https://github.com/golang/go/tree/master/src/crypto/sha256
+// Adaped from https://github.com/golang/go/tree/master/src/crypto/sha512
 
 module sha512
 
@@ -65,8 +65,6 @@ const (
 
 // digest represents the partial evaluation of a checksum.
 struct Digest {
-	// h        [8]uint64
-	// x        [chunk]byte
 mut:
 	h        []u64
 	x        []byte
@@ -123,8 +121,8 @@ mut:
 
 // Note: when u64 const is working remove this and uncomment above
 fn (d mut Digest) reset() {
-    d.h = [u64(0); 8]
-    d.x = [byte(0); Chunk]
+	d.h = [u64(0); 8]
+	d.x = [byte(0); Chunk]
 	switch d.function {
 	case crypto.Hash.SHA384:
 		d.h[0] = u64(0xcbbb9d5dc1059ed8)
@@ -154,14 +152,14 @@ fn (d mut Digest) reset() {
 		d.h[6] = u64(0x2b0199fc2c85b8aa)
 		d.h[7] = u64(0x0eb72ddc81c52ca2)
 	default:
-        d.h[0] = u64(0x6a09e667f3bcc908)
-        d.h[1] = u64(0xbb67ae8584caa73b)
-        d.h[2] = u64(0x3c6ef372fe94f82b)
-        d.h[3] = u64(0xa54ff53a5f1d36f1)
-        d.h[4] = u64(0x510e527fade682d1)
-        d.h[5] = u64(0x9b05688c2b3e6c1f)
-        d.h[6] = u64(0x1f83d9abfb41bd6b)
-        d.h[7] = u64(0x5be0cd19137e2179)
+		d.h[0] = u64(0x6a09e667f3bcc908)
+		d.h[1] = u64(0xbb67ae8584caa73b)
+		d.h[2] = u64(0x3c6ef372fe94f82b)
+		d.h[3] = u64(0xa54ff53a5f1d36f1)
+		d.h[4] = u64(0x510e527fade682d1)
+		d.h[5] = u64(0x9b05688c2b3e6c1f)
+		d.h[6] = u64(0x1f83d9abfb41bd6b)
+		d.h[7] = u64(0x5be0cd19137e2179)
 	}
 	d.nx = 0
 	d.len = u64(0)
@@ -173,22 +171,22 @@ fn _new(hash crypto.Hash) *Digest {
 	return d
 }
 
-// new returns a new hash.Hash computing the SHA-512 checksum.
+// new returns a new Digest (implementing hash.Hash) computing the SHA-512 checksum.
 pub fn new() *Digest {
 	return _new(crypto.Hash.SHA512)
 }
 
-// new512_224 returns a new hash.Hash computing the SHA-512/224 checksum.
+// new512_224 returns a new Digest (implementing hash.Hash) computing the SHA-512/224 checksum.
 fn new512_224() *Digest {
 	return _new(crypto.Hash.SHA512_224)
 }
 
-// new512_256 returns a new hash.Hash computing the SHA-512/256 checksum.
+// new512_256 returns a new Digest (implementing hash.Hash) computing the SHA-512/256 checksum.
 fn new512_256() *Digest {
 	return _new(crypto.Hash.SHA512_256)
 }
 
-// new384 returns a new hash.Hash computing the SHA-384 checksum.
+// new384 returns a new Digest (implementing hash.Hash) computing the SHA-384 checksum.
 fn new384() *Digest {
 	return _new(crypto.Hash.SHA384)
 }
@@ -237,22 +235,22 @@ fn (d mut Digest) sum(b_in mut []byte) []byte {
 	switch d0.function {
 	case crypto.Hash.SHA384:
 		for b in hash.left(Size384) {
-            b_in << b
-        }
+			b_in << b
+		}
 	case crypto.Hash.SHA512_224:
 		for b in hash.left(Size224) {
-            b_in << b
-        }
+			b_in << b
+		}
 	case crypto.Hash.SHA512_256:
 		for b in hash.left(Size256) {
-            b_in << b
-        }
+			b_in << b
+		}
 	default:
 		for b in hash {
-            b_in << b
-        }
+			b_in << b
+		}
 	}
-    return *b_in
+	return *b_in
 }
 
 fn (d mut Digest) checksum() []byte {
@@ -261,8 +259,8 @@ fn (d mut Digest) checksum() []byte {
 	mut tmp := [byte(0); 128]
 	tmp[0] = 0x80
 
-    if int(len)%128 < 112 {
-        d.write(tmp.left(112-int(len)%128))
+	if int(len)%128 < 112 {
+		d.write(tmp.left(112-int(len)%128))
 	} else {
 		d.write(tmp.left(128+112-int(len)%128))
 	}
@@ -271,7 +269,7 @@ fn (d mut Digest) checksum() []byte {
 	len <<= u64(3)
 
 	binary.big_endian_put_u64(tmp, u64(0)) // upper 64 bits are always zero, because len variable has type u64
-    binary.big_endian_put_u64(tmp.right(8), len)
+	binary.big_endian_put_u64(tmp.right(8), len)
 	d.write(tmp.left(16))
 
 	if d.nx != 0 {
@@ -280,7 +278,7 @@ fn (d mut Digest) checksum() []byte {
 
 	mut digest := [byte(0); Size]
 	
-    binary.big_endian_put_u64(digest, d.h[0])
+	binary.big_endian_put_u64(digest, d.h[0])
 	binary.big_endian_put_u64(digest.right(8), d.h[1])
 	binary.big_endian_put_u64(digest.right(16), d.h[2])
 	binary.big_endian_put_u64(digest.right(24), d.h[3])
@@ -306,7 +304,7 @@ pub fn sum384(data []byte) []byte {
 	mut d := _new(crypto.Hash.SHA384)
 	d.write(data)
 	sum := d.checksum()
-    sum384 := sum.left(Size384)
+	sum384 := sum.left(Size384)
 	return sum384
 }
 
@@ -315,7 +313,7 @@ pub fn sum512_224(data []byte) []byte {
 	mut d := _new(crypto.Hash.SHA512_224)
 	d.write(data)
 	sum := d.checksum()
-    sum224 := sum.left(Size224)
+	sum224 := sum.left(Size224)
 	return sum224
 }
 
@@ -324,14 +322,14 @@ pub fn sum512_256(data []byte) []byte {
 	mut d := _new(crypto.Hash.SHA512_256)
 	d.write(data)
 	sum := d.checksum()
-    sum256 := sum.left(Size256)
+	sum256 := sum.left(Size256)
 	return sum256
 }
 
 fn block(dig &Digest, p []byte) {
-    // For now just use block_generic until we have specific
+	// For now just use block_generic until we have specific
 	// architecture optimized versions
-    block_generic(dig, p)
+	block_generic(dig, p)
 }
 
 pub fn (d &Digest) size() int {
diff --git a/vlib/crypto/sha512/sha512block_generic.v b/vlib/crypto/sha512/sha512block_generic.v
index 3171649680..8ba2b288d4 100644
--- a/vlib/crypto/sha512/sha512block_generic.v
+++ b/vlib/crypto/sha512/sha512block_generic.v
@@ -180,6 +180,7 @@ fn block_generic(dig &Digest, p []byte) {
 	]
 	
 	mut w := [u64(0); 80]
+	
 	mut h0 := dig.h[0]
 	mut h1 := dig.h[1]
 	mut h2 := dig.h[2]
@@ -188,6 +189,7 @@ fn block_generic(dig &Digest, p []byte) {
 	mut h5 := dig.h[5]
 	mut h6 := dig.h[6]
 	mut h7 := dig.h[7]
+	
 	for p.len >= Chunk {
 		for i := 0; i < 16; i++ {
 			j := i * 8