101 lines
2.3 KiB
Go
101 lines
2.3 KiB
Go
package scha
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import (
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"errors"
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"crypto/sha512"
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"git.xdrm.io/schastsp/internal/xor"
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)
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/* (0) Static
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---------------------------------------------------------*/
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/* (1) Constants */
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const HSIZE uint16 = sha512.Size;
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const HBITSIZE uint32 = uint32(HSIZE) * 8;
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/* (1) Basic hash function
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*
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* @input<[]byte> Byte array input
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*
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* @return digest<[]byte]> Byte array digest
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*
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---------------------------------------------------------*/
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func hash(input []byte) []byte{
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/* (1) Create sha512 hasher */
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hasher := sha512.New();
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/* (2) Defer memory cleanup */
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defer hasher.Reset();
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/* (3) Set input to be hashed */
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hasher.Write(input);
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/* (4) Extract digest */
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return hasher.Sum(nil);
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}
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/* (2) Public hashing interface
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*
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* @input<[]byte> Byte array input
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* @depth<uint> Number of time to hash recursively (must be > 1)
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* @salt<[]byte> [OPT] Optional salt
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* @pepper<[]byte> [OPT] Optional pepper
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*
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* @return digest<[]byte]> Byte array digest
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* @return err<error> If consistence error
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*
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---------------------------------------------------------*/
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func Hash(input []byte, depth uint16, options... []byte) ([]byte, error) {
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/* (1) Manage errors errors
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---------------------------------------------------------*/
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/* (1) Avoid no depth (no hash at all) */
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if( depth < 1 ){
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return nil, errors.New("Cannot use a 'depth' of zero. This is inconsistent and means that no hash will be processed");
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}
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/* (2) Avoir empty input */
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if( len(input) < 1 ){
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return nil, errors.New("Cannot use an empty 'input'. This is inconsistent");
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}
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/* (2) Extract optional arguments
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---------------------------------------------------------*/
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/* (1) Optional salt */
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salt := make([]byte, 0)
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if len(options) > 0 { salt = options[0] }
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/* (2) Optional pepper */
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pepper := make([]byte, 0)
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if len(options) > 0 { pepper = options[0] }
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/* (3) Process cyclic hash
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---------------------------------------------------------*/
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/* (1) Initialise digest */
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digest := make([]byte, 0, HSIZE)
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/* (2) Process first hash + salt */
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digest = hash( xor.ByteArray(input, salt) )
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/* (3) Iterate @depth times */
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for depth--; depth > 0; depth-- {
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// Add Pepper only for last time
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if( depth == 1 ){
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digest = hash( xor.ByteArray(digest, pepper) )
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} else {
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digest = hash(digest)
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}
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}
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return digest, nil
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} |