Note: In order to use this module, run nimble install checksums.

SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest.

Please note that SHA-1 has been formally deprecated since 2011 and it is strongly recommended to switch to stronger hash functions such as the SHA-2 or SHA-3 family.

Even though SHA-1 is formally deprecated, this module itself is not deprecated and will continue to be usable.

See also

• base64 module for a Base64 encoder and decoder
• hashes module for efficient computations of hash values for diverse Nim types
• md5 module for the MD5 checksum algorithm
• sha2 module for the newer hash familiy SHA-2
• sha3 module for the newest hash family SHA-3

Example:

import src/checksums/sha1
let accessName = secureHash("John Doe")
assert $accessName == "AE6E4D1209F17B460503904FAD297B31E9CF6362"

Example: cmd: -r:off

import src/checksums/sha1
let
  a = secureHashFile("myFile.nim")
  b = parseSecureHash("10DFAEBF6BFDBC7939957068E2EFACEC4972933C")
assert a == b, "files don't match"

Types

SecureHash = distinct Sha1Digest

Sha1Digest = array[0 .. 20 - 1, uint8]

Sha1State = object

Procs

proc `$`(self: SecureHash): string {....raises: [], tags: [], forbids: [].}

Returns the string representation of a SecureHash.

See also:

• secureHash proc for generating a SecureHash from a string

Example:

let hash = secureHash("Hello World")
assert $hash == "0A4D55A8D778E5022FAB701977C5D840BBC486D0"

proc `==`(a, b: SecureHash): bool {....raises: [], tags: [], forbids: [].}

Checks if two SecureHash values are identical.

Example:

let
  a = secureHash("Hello World")
  b = secureHash("Goodbye World")
  c = parseSecureHash("0A4D55A8D778E5022FAB701977C5D840BBC486D0")
assert a != b
assert a == c

proc finalize(ctx: var Sha1State): Sha1Digest {....raises: [], tags: [],
    forbids: [].}

Finalizes the Sha1State and returns a Sha1Digest.

If you use the secureHash proc, there’s no need to call this function explicitly.

proc isValidSha1Hash(s: string): bool {....raises: [], tags: [], forbids: [].}

Checks if a string is a valid sha1 hash sum.

proc newSha1State(): Sha1State {....raises: [], tags: [], forbids: [].}

Creates a Sha1State.

If you use the secureHash proc, there’s no need to call this function explicitly.

proc parseSecureHash(hash: string): SecureHash {....raises: [ValueError], tags: [],
    forbids: [].}

Converts a string hash to a SecureHash.

See also:

• secureHash proc for generating a SecureHash from a string
• secureHashFile proc for generating a SecureHash from a file

Example:

let
  hashStr = "0A4D55A8D778E5022FAB701977C5D840BBC486D0"
  secureHash = secureHash("Hello World")
assert secureHash == parseSecureHash(hashStr)

proc secureHash(str: openArray[char]): SecureHash {....raises: [], tags: [],
    forbids: [].}

Generates a SecureHash from str.

See also:

• secureHashFile proc for generating a SecureHash from a file
• parseSecureHash proc for converting a string hash to SecureHash

Example:

let hash = secureHash("Hello World")
assert hash == parseSecureHash("0A4D55A8D778E5022FAB701977C5D840BBC486D0")

proc secureHashFile(filename: string): SecureHash {....raises: [IOError],
    tags: [ReadIOEffect], forbids: [].}

Generates a SecureHash from a file.

See also:

• secureHash proc for generating a SecureHash from a string
• parseSecureHash proc for converting a string hash to SecureHash

proc update(ctx: var Sha1State; data: openArray[char]) {....raises: [], tags: [],
    forbids: [].}

Updates the Sha1State with data.

If you use the secureHash proc, there’s no need to call this function explicitly.