MD5 128 bits is represented as 22 characters in Base64. These 2 equal signs add no information whatsoever to the string, and can be discarded when storing. Since MD5 has 16 bytes of information, many Base64 encoding algorithms append "=" to designate that the input of 16 bytes was 2 bytes short of the next multiple of 3, which would have been 18 bytes. This is because Base64 represents 3 bytes of information as 4 characters. I mentioned above that many Base64 encoding algorithms add a couple of characters of padding when encoding an MD5 value. Since 128 bits cannot fit within 21 characters but does fit within 22 characters (with a little room to spare), a 128-bit value will always be represented as 22 characters in Base64. With 6 bits of information in every character, 21 characters has 126 bits of information, and 22 characters contains 132 bits of information. Every character in a Base64 string contains 6 bits of information, because there are 64 possible values for the character, and it takes 6 powers of 2 to reach 64. Only the first 22 characters matter.Īn MD5 hash is a 128-bit value. The padding adds no useful information and can be discarded. Many Base64 algorithms will also append 2 characters of padding when encoding an MD5 hash, bringing the total to 24 characters. Tr圜omputeHash(ReadOnlySpan, Span, Int32)Īttempts to compute the hash value for the specified byte array.Īttempts to compute the hash of data using the MD5 algorithm.Īttempts to finalize the hash computation after the last data is processed by the hash algorithm.An MD5 value is always 22 (useful) characters long in Base64 notation. TransformBlock(Byte, Int32, Int32, Byte, Int32)Ĭomputes the hash value for the specified region of the input byte array and copies the specified region of the input byte array to the specified region of the output byte array. Returns a string that represents the current object. Resets the hash algorithm to its initial state.Ĭreates a shallow copy of the current Object. When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic hash algorithm. HashDataAsync(Stream, Memory, CancellationToken) Routes data written to the object into the hash algorithm for computing the hash.Ĭomputes the hash of data using the MD5 algorithm.Ĭomputes the hash of a stream using the MD5 algorithm.Īsynchronously computes the hash of a stream using the MD5 algorithm. When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash. Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.ĭetermines whether the specified object is equal to the current object. Releases all resources used by the current instance of the HashAlgorithm class. Releases all resources used by the HashAlgorithm class.Ĭomputes the hash value for the specified byte array.Ĭomputes the hash value for the specified region of the specified byte array.Ĭomputes the hash value for the specified Stream object.ĬomputeHashAsync(Stream, CancellationToken)Īsynchronously computes the hash value for the specified Stream object.Ĭreates an instance of the default implementation of the MD5 hash algorithm.Ĭreates an instance of the specified implementation of the MD5 hash algorithm. When overridden in a derived class, gets the output block size. When overridden in a derived class, gets the input block size. Gets the size, in bits, of the computed hash code. Gets the value of the computed hash code. When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed. Gets a value indicating whether the current transform can be reused. Represents the state of the hash computation. Represents the value of the computed hash code. Represents the size, in bits, of the computed hash code. The hash size produced by the MD5 algorithm, in bytes. The hash size produced by the MD5 algorithm, in bits. Use MD5 only for compatibility with legacy applications and data. Consider using the SHA256 class or the SHA512 class instead of the MD5 class. Due to collision problems with MD5/SHA1, Microsoft recommends SHA256 or SHA512.
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