diff --git a/vlib/crypto/md5/md5.v b/vlib/crypto/md5/md5.v
index d264d92561..2d56d5513f 100644
--- a/vlib/crypto/md5/md5.v
+++ b/vlib/crypto/md5/md5.v
@@ -52,7 +52,7 @@ pub fn new() &Digest {
 }
 
 // write writes the contents of `p_` to the internal hash representation.
-pub fn (mut d Digest) write(p_ []byte) int {
+pub fn (mut d Digest) write(p_ []byte) ?int {
 	unsafe {
 		mut p := p_
 		nn := p.len
@@ -110,7 +110,7 @@ pub fn (mut d Digest) checksum() []byte {
 	tmp[0] = 0x80
 	pad := ((55 - d.len) % 64) // calculate number of padding bytes
 	binary.little_endian_put_u64(mut tmp[1 + pad..], d.len << 3) // append length in bits
-	d.write(tmp[..1 + pad + 8])
+	d.write(tmp[..1 + pad + 8]) or { panic(err) }
 	// The previous write ensures that a whole number of
 	// blocks (i.e. a multiple of 64 bytes) have been hashed.
 	if d.nx != 0 {
@@ -127,7 +127,7 @@ pub fn (mut d Digest) checksum() []byte {
 // sum returns the MD5 checksum of the data.
 pub fn sum(data []byte) []byte {
 	mut d := new()
-	d.write(data)
+	d.write(data) or { panic(err) }
 	return d.checksum()
 }
 
diff --git a/vlib/crypto/sha1/sha1.v b/vlib/crypto/sha1/sha1.v
index f0db1b07f6..2e4b6fe66f 100644
--- a/vlib/crypto/sha1/sha1.v
+++ b/vlib/crypto/sha1/sha1.v
@@ -56,7 +56,7 @@ pub fn new() &Digest {
 
 // write writes the contents of `p_` to the internal hash representation.
 [manualfree]
-pub fn (mut d Digest) write(p_ []byte) int {
+pub fn (mut d Digest) write(p_ []byte) ?int {
 	nn := p_.len
 	unsafe {
 		mut p := p_
@@ -109,14 +109,14 @@ fn (mut d Digest) checksum() []byte {
 	mut tmp := []byte{len: (64)}
 	tmp[0] = 0x80
 	if int(len) % 64 < 56 {
-		d.write(tmp[..56 - int(len) % 64])
+		d.write(tmp[..56 - int(len) % 64]) or { panic(err) }
 	} else {
-		d.write(tmp[..64 + 56 - int(len) % 64])
+		d.write(tmp[..64 + 56 - int(len) % 64]) or { panic(err) }
 	}
 	// Length in bits.
 	len <<= 3
 	binary.big_endian_put_u64(mut tmp, len)
-	d.write(tmp[..8])
+	d.write(tmp[..8]) or { panic(err) }
 	mut digest := []byte{len: (size)}
 	binary.big_endian_put_u32(mut digest, d.h[0])
 	binary.big_endian_put_u32(mut digest[4..], d.h[1])
@@ -129,7 +129,7 @@ fn (mut d Digest) checksum() []byte {
 // sum returns the SHA-1 checksum of the bytes passed in `data`.
 pub fn sum(data []byte) []byte {
 	mut d := new()
-	d.write(data)
+	d.write(data) or { panic(err) }
 	return d.checksum()
 }
 
diff --git a/vlib/crypto/sha256/sha256.v b/vlib/crypto/sha256/sha256.v
index 191bc8cc8e..af37727c7d 100644
--- a/vlib/crypto/sha256/sha256.v
+++ b/vlib/crypto/sha256/sha256.v
@@ -90,7 +90,7 @@ pub fn new224() &Digest {
 }
 
 // write writes the contents of `p_` to the internal hash representation.
-fn (mut d Digest) write(p_ []byte) int {
+fn (mut d Digest) write(p_ []byte) ?int {
 	unsafe {
 		mut p := p_
 		nn := p.len
@@ -147,14 +147,14 @@ fn (mut d Digest) checksum() []byte {
 	mut tmp := []byte{len: (64)}
 	tmp[0] = 0x80
 	if int(len) % 64 < 56 {
-		d.write(tmp[..56 - int(len) % 64])
+		d.write(tmp[..56 - int(len) % 64]) or { panic(err) }
 	} else {
-		d.write(tmp[..64 + 56 - int(len) % 64])
+		d.write(tmp[..64 + 56 - int(len) % 64]) or { panic(err) }
 	}
 	// Length in bits.
 	len <<= u64(3)
 	binary.big_endian_put_u64(mut tmp, len)
-	d.write(tmp[..8])
+	d.write(tmp[..8]) or { panic(err) }
 	if d.nx != 0 {
 		panic('d.nx != 0')
 	}
@@ -181,14 +181,14 @@ pub fn sum(data []byte) []byte {
 // sum256 returns the SHA256 checksum of the data.
 pub fn sum256(data []byte) []byte {
 	mut d := new()
-	d.write(data)
+	d.write(data) or { panic(err) }
 	return d.checksum()
 }
 
 // sum224 returns the SHA224 checksum of the data.
 pub fn sum224(data []byte) []byte {
 	mut d := new224()
-	d.write(data)
+	d.write(data) or { panic(err) }
 	sum := d.checksum()
 	sum224 := []byte{len: (size224)}
 	copy(sum224, sum[..size224])
diff --git a/vlib/crypto/sha512/sha512.v b/vlib/crypto/sha512/sha512.v
index c729f2282b..0ddff114e1 100644
--- a/vlib/crypto/sha512/sha512.v
+++ b/vlib/crypto/sha512/sha512.v
@@ -149,7 +149,7 @@ fn new384() &Digest {
 }
 
 // write writes the contents of `p_` to the internal hash representation.
-fn (mut d Digest) write(p_ []byte) int {
+fn (mut d Digest) write(p_ []byte) ?int {
 	unsafe {
 		mut p := p_
 		nn := p.len
@@ -219,15 +219,15 @@ fn (mut d Digest) checksum() []byte {
 	mut tmp := []byte{len: (128)}
 	tmp[0] = 0x80
 	if int(len) % 128 < 112 {
-		d.write(tmp[..112 - int(len) % 128])
+		d.write(tmp[..112 - int(len) % 128]) or { panic(err) }
 	} else {
-		d.write(tmp[..128 + 112 - int(len) % 128])
+		d.write(tmp[..128 + 112 - int(len) % 128]) or { panic(err) }
 	}
 	// Length in bits.
 	len <<= u64(3)
 	binary.big_endian_put_u64(mut tmp, u64(0)) // upper 64 bits are always zero, because len variable has type u64
 	binary.big_endian_put_u64(mut tmp[8..], len)
-	d.write(tmp[..16])
+	d.write(tmp[..16]) or { panic(err) }
 	if d.nx != 0 {
 		panic('d.nx != 0')
 	}
@@ -248,14 +248,14 @@ fn (mut d Digest) checksum() []byte {
 // sum512 returns the SHA512 checksum of the data.
 pub fn sum512(data []byte) []byte {
 	mut d := new_digest(.sha512)
-	d.write(data)
+	d.write(data) or { panic(err) }
 	return d.checksum()
 }
 
 // sum384 returns the SHA384 checksum of the data.
 pub fn sum384(data []byte) []byte {
 	mut d := new_digest(.sha384)
-	d.write(data)
+	d.write(data) or { panic(err) }
 	sum := d.checksum()
 	sum384 := []byte{len: (size384)}
 	copy(sum384, sum[..size384])
@@ -265,7 +265,7 @@ pub fn sum384(data []byte) []byte {
 // sum512_224 returns the Sum512/224 checksum of the data.
 pub fn sum512_224(data []byte) []byte {
 	mut d := new_digest(.sha512_224)
-	d.write(data)
+	d.write(data) or { panic(err) }
 	sum := d.checksum()
 	sum224 := []byte{len: (size224)}
 	copy(sum224, sum[..size224])
@@ -275,7 +275,7 @@ pub fn sum512_224(data []byte) []byte {
 // sum512_256 returns the Sum512/256 checksum of the data.
 pub fn sum512_256(data []byte) []byte {
 	mut d := new_digest(.sha512_256)
-	d.write(data)
+	d.write(data) or { panic(err) }
 	sum := d.checksum()
 	sum256 := []byte{len: (size256)}
 	copy(sum256, sum[..size256])